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INTERNET-DRAFT J. Loughney
Internet Engineering Task Force Nokia
G. Sidebottom, Guy Mousseau
Issued: 4 October 2000 Nortel Networks
Expires: 4 May 2001 S. Lorusso
Unisphere Solutions
SS7 SCCP-User Adaptation Layer (SUA)
<draft-ietf-sigtran-sua-02.txt>
Status of This Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC 2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as 'work in progress.'
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html .
This draft expires on 4 May 2001
Abstract
This Internet Draft defines a protocol for the transport of any SS7
SCCP-User signaling (e.g., TCAP, RANAP, etc.) over IP using the
Stream Control Transport Protocol. The protocol should be modular
and symmetric, to allow it to work in diverse architectures, such as
a Signaling Gateway to IP Signaling Endpoint architecture as well as
a peer-to-peer IP Signaling Endpoint architecture. Protocol elements
are added to allow seamless operation between peers in the SS7 and IP
domains.
Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
Abstract...............................................................1
1. Introduction........................................................3
1.1 Scope ............................................................3
1.2 Terminology ......................................................3
1.3 Signaling Transport Architecture .................................5
1.4 Services Provided by the SUA Layer ...............................9
1.5 Internal Functions Provided in the SUA Layer ....................10
1.6 Definition of SUA Boundaries ....................................11
2 Protocol Elements...................................................11
2.1 Common Message Header ...........................................12
2.2 SUA Connectionless Messages .....................................13
2.3 Connection Oriented Messages ....................................15
2.4 SS7 Signaling Network Management Messages .......................21
2.5 Application Server Process Maintenance Messages .................24
2.6 ASP Traffic Maintenance Messages ................................26
2.7 Management Messages .............................................29
2.8 Common Parameters ...............................................31
2.9 SUA-Specific parameters .........................................35
3 Procedures..........................................................42
3.1 Peer Message Procedures .........................................42
3.2 Signaling Gateway Related Procedures ............................42
3.3 Layer Management Procedures .....................................43
3.4 SCTP Management Procedures ......................................43
4 Examples of SUA Procedures..........................................48
4.1 Establishment of Association ....................................48
4.2 ASP fail-over Procedures ........................................49
4.3 SUA/SCCP-User Boundary Examples .................................49
5 Security............................................................49
5.1 Introduction ....................................................49
5.2 Threats .........................................................49
5.3 Protecting Confidentiality ......................................50
6 IANA Considerations.................................................50
6.1 SCTP Payload Protocol ID ........................................50
6.2 Port Number .....................................................50
7 Timer Values........................................................50
8 Acknowledgements....................................................50
9 Authors' Addresses..................................................51
10 References.........................................................51
Appendix A: Message mapping between SCCP and SUA......................52
Appendix B: SCTP to SUA Message Mapping Examples......................53
Copyright Statement...................................................53
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
1. Introduction
1.1 Scope
There is on-going integration of SCN networks and IP networks.
Network service providers are designing all IP architectures which
include support for SS7 and SS7-like signaling protocols. IP provides
an effective way to transport user data and for operators to expand
their networks and build new services. In these networks, there may
be some need for interworking between the SS7 and IP domains.
This document details the delivery of SCCP-user messages (MAP & CAP
over TCAP, RANAP, etc.) and new third generation network protocol
messages over IP between two signaling endpoints. Consideration is
given for the transport from an SS7 Signaling Gateway (SG) to an IP
signaling node (such as an IP-resident Database) as described in the
Framework Architecture for Signaling Transport [2719]. This protocol
can also support transport of SCCP-user messages between two
endpoints wholly contained within an IP network.
The delivery mechanism SHOULD meet the following criteria:
* Support for transfer of SS7 SCCP-User Part messages (e.g., TCAP,
RANAP, etc.)
* Support for SCCP connectionless service.
* Support for SCCP connection oriented service.
* Support for the seamless operation of SCCP-User protocol peers
* Support for the management of SCTP transport associations between
a SG and one or more IP-based signaling nodes).
* Support for distributed IP-based signaling nodes.
* Support for the asynchronous reporting of status changes to
management
The protocol is modular in design, allowing different implementations
to be made, based upon the environment that needs to be supported.
Deepending upon the upper layer protocol supported, the SUA will need
to support SCCP connectionless service, SCCP connect-orient service
or both services.
1.2 Terminology
Signaling Gateway (SG) - Network element that terminates SCN
signaling and transports SCCP-User signaling over IP to an IP
signaling endpoint. A Signaling Gateway could be modeled as one or
more Application Servers, which is located at the border of the SS7
and IP networks.
Application Server (AS) - A logical entity serving a specific Routing
Key. An example of an Application Server is an IP database handling
all request for a unique set of SCCP-users. The AS contains a set of
one or more unique Application Server Processes, of which one or more
is normally actively processing traffic.
Application Server Process (ASP) - An Application Server Process
serves as an active or standby process of an Application Server
(e.g., part of a distributed signaling node or database element).
Examples of ASPs are MGCs, IP SCPs, or IP-based HLRs. An ASP
contains an SCTP end-point and may be configured to process traffic
within more than one Application Server.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
Association - An association refers to an SCTP association. The
association provides the transport for the delivery of SCCP-User
protocol data units and SUA adaptation layer peer messages.
Routing Key - The Routing Key describes a set of SS7 parameter and
/or parameter-ranges that uniquely defines the range of signaling
traffic configured to be handled by a particular Application Server.
An example would be where a Routing Key consists of a particular PC
and SSN to which all traffic would be directed to a particular
Application Server. Routing Keys are mutually exclusive in the sense
that a received SS7 signaling message cannot be directed to more than
one Routing Key. A Routing Key cannot extend across more than a
single SS7 PC, in order to more easily support SS7 Management
procedures. It is not necessary for the parameter ranges within a
particular Routing Key to be contiguous.
Routing Context - An Application Server Process may be configured to
process traffic within more than one Application Server. In this
case, the Routing Context parameter is exchanged between two ASPs,
identifying the relevant Application Server. From the perspective of
an ASP, the Routing Context uniquely identifies the range of traffic
associated with a particular Application Server, which the ASP is
configured to receive. There is a 1:1 relationship between a Routing
Context value and a Routing Key within an AS. Therefore the Routing
Context can be viewed as an index into an AS Table containing the AS
Routing Keys.
Fail-over - The capability to re-route signaling traffic as required
to an alternate Application Server Process, or group of ASPs, within
an Application Server in the event of failure or unavailability of a
currently used Application Server Process. Fail-back may apply upon
the return to service of a previously unavailable Application Server
Process.
Signaling Point Management Cluster (SPMC) - A complete set of
Application Servers represented to the SS7 network under the same SS7
Point Code. SPMCs are used to sum the availability / congestion /
User_Part status of an SS7 destination point code that is distributed
in the IP domain, for the purpose of supporting management procedures
at an SG.
Network Appearance - The Network Appearance identifies an SS7 network
context for the purposes of logically separating the signaling
traffic between the SG and the Application Server Processes over a
common SCTP Association. An example is where an SG is logically
partitioned to appear as an element in four separate national SS7
networks. A Network Appearance implicitly defines the SS7 Point
Code(s), Network Indicator and SCCP protocol type/variant/version
used within a specific SS7 network partition. An physical SS7 route-
set or link-set at an SG can appear in only one network appearance.
The Network Appearance is not globally significant and requires
coordination only between the SG and the ASP.
Network Byte Order - Most significant byte first, a.k.a. Big Endian.
Layer Management - Layer Management is a nodal function in an SG or
ASP that handles the inputs and outputs between the SUA layer and a
local management entity.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
Host - The computing platform that the ASP process is running on.
Stream - A stream refers to an SCTP stream; a uni-directional logical
channel established from one SCTP endpoint to another associated SCTP
endpoint, within which all user messages are delivered in-sequence
except for those submitted to the un-ordered delivery service.
Transport address - an address which serves as a source or
destination for the unreliable packet transport service used by SCTP.
In IP networks, a transport address is defined by the combination of
an IP address and an SCTP port number. Note, only one SCTP port may
be defined for each endpoint, but each SCTP endpoint may have
multiple IP addresses.
1.3 Signaling Transport Architecture
The framework architecture that has been defined for SCN signaling
transport over IP [2719] uses multiple components, including an IP
transport protocol, a signaling common transport protocol and an
adaptation module to support the services expected by a particular
SCN signaling protocol from its underlying protocol layer.
In general terms, the SUA architecture can be modeled as a peer-to-
peer architecture.
1.3.1 Protocol Architecture for TCAP Transport
In this architecture, the SCCP and SUA layers interface in the SG.
There needs to be interworking between the SCCP and SUA layers to
provide for the seamless transfer of the user messages as well as the
management messages. The SUA handles the SS7 address to IP address
mapping.
******** SS7 *************** IP ********
* SEP *---------* *--------* *
* or * * SG * * ASP *
* STP * * * * *
******** *************** ********
+------+ +------+
| TCAP | | TCAP |
+------+ +------+------+ +------+
| SCCP | | SCCP | SUA | | SUA |
+------+ +------+------+ +------+
| MTP3 | | MTP3 | | | |
+------| +------+ SCTP | | SCTP |
| MTP2 | | MTP2 | | | |
+------+ +------+------+ +------+
| L1 | | L1 | IP | | IP |
+------+ +------+------+ +------+
| | | |
+---------------+ +------------+
TCAP - Transaction Capability Application Protocol
STP - SS7 Signaling Transfer Point
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
1.3.2 Protocol Architecture for RANAP Transport
In this architecture, the SS7 application protocol is invoked at the
SG. For messages destined for an ASP, the SUA handles address
translation, for example by way of Global Title Translation or via
mapping table, resolving the destination specified by SS7 Application
to a SCTP association / IP address.
******** SS7 *************** IP ********
* SEP *---------* *--------* *
* or * * SG * * ASP *
* STP * * * * *
******** *************** ********
+------+ +-------------+ +------+
| S7AP | | S7AP | | S7AP |
+------+ +------+------+ +------+
| SCCP | | SCCP | SUA | | SUA |
+------+ +------+------+ +------+
| MTP3 | | MTP3 | | | |
+------| +------+ SCTP | | SCTP |
| MTP2 | | MTP2 | | | |
+------+ +------+------+ +------+
| L1 | | L1 | IP | | IP |
+------+ +------+------+ +------+
| | | |
+---------------+ +------------+
S7AP - SS7 Application Protocol (e.g. - RANAP/RNSAP)
STP - SS7 Signaling Transfer Point
This architecture may simplify, in some cases, to carrying an SS7
application protocol between two IP based endpoints. In this
scenario, full SG functionality may not be needed. This architecture
is considered in the next section.
1.3.3 All IP Architecture
This architecture can be used to carry a protocol which uses the
transport services of SCCP, but is contained with an IP network.
This allows extra flexibility in developing networks, especially when
interaction between legacy signaling is not needed. The architecture
removes the need for signaling gateway functionality.
******** IP ********
* *--------* *
* AS * * AS *
* * * *
******** ********
+------+ +------+
| AP | | AP |
+------+ +------+
| SUA | | SUA |
+------+ +------+
| SCTP | | SCTP |
+------+ +------+
| IP | | IP |
+------+ +------+
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
| |
+----------------+
AP - Application Protocol (e.g. - RANAP/RNSAP)
In the case where a collision occurs during initiation, there exist
two possible solutions: 1) if there are sufficient resources, both
initiations could be accepted; 2) both ASPs should back-off and after
some amount of time, later re-establish an initiation.
1.3.4 Generalized Point-to-Point Network Architecture
Figure 1 shows an example network architecture which can support
robust operation and failover support. There needs to be some
management resources at the AS to manage traffic.
***********
* AS1 *
* +-----+ * SCTP Associations
* |ASP1 +-------------------+
* +-----+ * | ***********
* * | * AS3 *
* +-----+ * | * +-----+ *
* |ASP2 +-----------------------------------------+ASP1 | *
* +-----+ * | * +-----+ *
* * | * *
* +-----+ * | * +-----+ *
* |ASP3 | * +--------------------------+ASP2 | *
* +-----+ * | | * +-----+ *
*********** | | ***********
| |
*********** | | ***********
* AS2 * | | * AS4 *
* +-----+ * | | * +-----+ *
* |ASP1 +--------------+ +---------------------+ASP1 | *
* +-----+ * * +-----+ *
* * * *
* +-----+ * * +-----+ *
* |ASP2 +-----------------------------------------+ASP1 | *
* +-----+ * * +-----+ *
* * ***********
* +-----+ *
* |ASP3 | *
* +-----+ *
* *
***********
Figure 1: Generalized Architecture
In this example, the Application Servers are shown residing within
one logical box, with ASPs located inside. In fact, an AS could be
distributed among several hosts. In such a scenario, the host should
share state as protection in the case of a failure. Additionally, in
a distributed system, one ASP could be registered to more than one
AS. This draft should not restrict such systems - though such a case
in not specified.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
1.3.5 Generalized Signaling Gateway Network Architecture
When interworking between SS7 and IP domains is needed, the SG acts
as the gateway node between the SS7 network and the IP network. The
SG will transport SCCP-user signaling traffic from the SS7 network to
the IP-based signaling nodes (for example IP-resident Databases).
The Signaling Gateway can be considered as a group of Application
Servers with additional functionality to interface towards an SS7
network.
The SUA protocol should be flexible enough to allow different
configurations and transport technology to allow the network
operators to meet their operation, management and performance
requirements.
Figure 2 shows a possible realization of this architecture, with
Signaling Gateway functionality.
Signaling Gateway
****************
* +----------+ * **************
* | AS1 | * * AS3 *
* | ******** | * * ******** *
* | * ASP1 +---------------------------------------------+ ASP1 * *
* | ******** | * * ******** *
* | ******** | * * ******** *
* | * ASP2 +--------------------------+ +----------+ ASP2 * *
* | ******** | * | | * ******** *
* +----------+ * | | * . *
* +----------+ * | | * . *
* | AS2 | * | | * . *
* | ******** | * | | * ******** *
* | * ASP1 +----------------------------------+ * * ASPN * *
* | ******** | * SCTP Associations | * ******** *
* | ******** | * | **************
* | * ASP2 +---------------- |
* | ******** | * | | **************
* +----------+ * | | * AS4 *
**************** | | * ******** *
| +------------------+ ASP1 * *
| * ******** *
| * . *
| * . *
| * *
| * ******** *
+-----------------------------+ ASPn * *
* ******** *
**************
Figure 2: Signaling Gateway Architecture
1.3.6 ASP Fail-over Model and Terminology
The SUA protocol supports ASP fail-over functions in order to support
a high availability of transaction processing capability.
An Application Server can be considered as a list of all ASPs
configured/registered to handle SCCP-user messages within a certain
range of routing information, known as a Routing Key. One or more
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
ASPs in the list may normally be active to handle traffic, while
others may while any others are inactive but available in the event
of failure or unavailability of the active ASP(s).
The fail-over model supports an "n+k" redundancy model, where "n"
ASPs is the minimum number of redundant ASPs required to handle
traffic and "k" ASPs are available to take over for a failed or
unavailable ASP. Note that "1+1" active/standby redundancy is a
subset of this model. A simplex "1+0" model is also supported as a
subset, with no ASP redundancy.
To avoid a single point of failure, it is recommended that a minimum
of two ASPs be resident in the list, resident in separate physical
hosts and therefore available over different SCTP Associations.
1.4 Services Provided by the SUA Layer
1.4.1 Support for the transport of SCCP-User Messages
The SUA needs to support the transfer of SCCP-user messages. The SUA
layer at the SG needs to seamlessly transport the user messages.
1.4.2 SCCP Protocol Class Support
Depending upon the SCCP-users supported, the SUA shall support the 4
possible SCCP protocol classes transparently. The SCCP protocol
classes are defined as follows:
* Protocol class 0 provides unordered transfer of SCCP-user
messages in a connectionless manner.
* Protocol class 1 allows the SCCP-user to select the in-sequence
delivery of SCCP-user messages in a connectionless manner.
* Protocol class 2 allows the bi-directional transfer of SCCP-user
messages by setting up a temporary or permanent signaling
connection.
* Protocol class 3 allows the features of protocol class 2 with
the inclusion of flow control. Detection of message loss or
mis-sequencing is included.
Protocol classes 0 and 1 make up the SCCP connectionless service.
Protocol classes 2 and 3 make up the SCCP connection-oriented
service.
1.4.3 Native Management Functions
The SUA layer may provide management of the underlying SCTP layer to
ensure that transport is available according to the degree specified
by the SCCP-user application.
The SUA layer provides the capability to indicate errors associated
with the SUA-protocol messages and to provide notification to local
management and the remote peer as is necessary.
1.4.4 Interworking with SCCP Network Management Functions
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
The SUA layer needs to support the following SCCP network management
functions:
Coord Request
Coord Indication
Coord Response
Coord Confirm
State Request
State Indication
Pcstate Indication
1.4.5 Support for the management between the SG and ASP.
The SUA layer should provide interworking with SCCP management
functions at the SG for seamless inter-operation between the SCN
network and the IP network. It should:
* Provide an indication to the SCCP-user at an ASP
that a remote SS7 endpoint/peer is unreachable.
* Provide an indication to the SCCP-user at an ASP
that a remote SS7 endpoint/peer is reachable.
* Provide congestion indication to SCCP-user at an ASP.
* Provide the initiation of an audit of remote SS7
endpoints at the SG.
1.5 Internal Functions Provided in the SUA Layer
1.5.1 Address Translation and Mapping at the SG
SCCP users may present the following options to address their peer
endpoints:
Global Title
PC + SSN
Host Name
IP Address(es)
Global Titles are an interesting option for addressing. Currently,
the ITU does not support translation of Global Titles to IP
addresses. However, IP addresses are global in scope. There exist
many proprietary schemes for managing SS7 Address Translation to IP
addresses, and is considered outside of the scope of this document to
specify how this is done.
Some discussion of address translation should be made to insure
interoperability between implementations of the SUA. For further
instruction in the use of Global Titles the rules detailed in Annex B
of ITU Q.713 [ITU SCCP] or [ANSI SCCP] should be consulted.
That being said, currently, there is some work within the IETF
studying translation of E.164 numbers to Host Names [ENUMS], [E.164-
DNS].
In many cases, the network operator may have some control over the
SCCP-user protocols being transported by SUA. If possible, the Upper
Layer can present a Host Name or IP Address, which then can be
directly passed to SCTP.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
An example of address translation at the SG would be that the CDPA is
extracted from the SCCP Header, processed by the SUA routing function
which yields a SA. The SA is fed back into extended SUA routing
analysis which yields the ASP to route the message to. This is why
the Source Address and Destination address-routing should be
performed based on the CDPA.
1.5.2 SCTP Stream Mapping
The SUA supports SCTP streams. The SG/AS needs to maintain a list of
SCTP and SUA-users for mapping purposes. SCCP-users requiring
sequenced message transfer need to be sent over a stream supporting
sequenced delivery.
SUA MUST use stream 0 for SUA management messages. It is recommended
that sequenced delivery be in order to preserve the order of
management message delivery.
1.6 Definition of SUA Boundaries
1.6.1 Definition of the upper boundary
The following primitives are supported between the SUA and an SCCP-
user.
Unit Data Request
Unit Data Indication
Notice Indication
Connect Request
Connect Indication
Connect Responding
Connect Confirm
Data Request
Data Indication
Expedited Data Request
Expedited Data Indication
Disconnect Request
Disconnect Indication
Reset Request
Reset Indication
Reset Response
Reset Confirm
1.6.2 Definition of the lower boundary
The upper layer primitives provided by the SCTP are provided in
[SCTP].
2 Protocol Elements
The general message format includes a Common Message Header together
with a list of zero or more parameters as defined by the Message
Type.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
For forward compatibility, all Message Types may have attached
parameters even if none are specified in this version.
2.1 Common Message Header
The protocol messages for the SCCP-User Adaptation Protocol requires
a message structure which contains a version, message type, message
length and message contents. This message header is common among
all signaling protocol adaptation layers:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Reserved | Message Class | Message Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| msg data |
Note that the 'data' portion of SUA messages SHALL contain SCCP-User
data, not the encapsulated SCCP message.
Optional parameters can only occur at most once in an SUA message.
2.1.1 SUA Protocol Version
The version field (ver) contains the version of the SUA adaptation
layer. The supported versions are:
01 SUA version 1.0
2.1.2 Message Classes
Message Classes
0 Management (MGMT) Message
1 Reserved
2 SS7 Signaling Network Management (SSNM) Messages
3 ASP State Maintenance (ASPSM) Messages
4 ASP Traffic Maintenance (ASPTM) Messages
5 Reserved
6 Reserved
7 Connectionless Messages
9 Connection-Oriented Messages
8 - 255 Reserved
2.1.3 Message Types
SUA Management Messages
0 Error (ERR)
1 Audit (AUD)
2 Notify (NTFY)
3 - 255 Reserved
SS7 Signaling Network Management (SSNM) Messages
0 Reserved
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
1 Destination Unavailable (DUNA)
2 Destination Available (DAVA)
3 Destination State Audit (DAUD)
4 Destination User Part Unavailable (DUPU)
5 SCCP Management (SCMG)
6 - 255 Reserved for SSNM Messages
Application Server Process Maintenance (ASPM) Messages
0 Reserved
1 ASP Up (UP)
2 ASP Down (DOWN)
3 Heartbeat (HEARTBEAT)
4 ASP Up Ack (UP ACK)
5 ASP Down Ack (Down ACK)
6 - 255 Reserved for ASPSM Messages
ASP Traffic Maintenance (ASPTM) Messages
0 Reserved
1 ASP Active (ACTIVE)
2 ASP Inactive (INACTIVE)
3 ASP Active Ack (ACTIVE ACK)
4 ASP Inactive Ack (INACTIVE ACK)
5 to 255 Reserved for ASPTM Messages
Connectionless Messages
0 Reserved
1 Connectionless Data Transfer (CLDT)
2 Connectionless Data Response (CLDR)
3 - 255 Reserved
Connection-Oriented Messages
0 Reserved
1 Connection Request (CORE)
2 Connection Acknowledge (COAK)
3 Connection Refused (COREF)
4 Release Request (RELRE)
5 Release Complete (RELCO)
6 Reset Confirm (RESCO)
7 Reset Request (RESRE)
8 Connection Oriented Data Transfer (CODT)
9 Connection Oriented Data Acknowledge (CODA)
10 - 255 reserved
2.1.4 Message Length
The Message Length defines the length of the message in octets,
including the header.
2.2 SUA Connectionless Messages
The following section describes the SUA Connectionless transfer
messages and parameter contents. The general message format includes
a Common Message Header together with a list of zero or more
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
parameters as defined by the Message Type. All Message Types can
have attached parameters.
2.2.1 Connectionless Data Transfer
This message transfers data between one SUA to another.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0102 | Parameter Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Source Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0103 | Parameter Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ destination address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0003 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Flags Mandatory
Source Address Mandatory
Destination Address Mandatory
Data Mandatory
Implementation note:
This message covers the following SCCP messages: unitdata (UDT),
extended unitdata (XUDT), long unitdata (LUDT).
2.2.2 Connectionless Data Response
This message is used as a response message by the peer and/or report
errors.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0104 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SCCP Error Cause |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0102 | Length |
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Source Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0103 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ destination address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0003 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Fixed Lengths Parameters
Flags Mandatory
Return Cause Mandatory
Source Address Mandatory
Destination Address Mandatory
Data Optional
Implementation note:
This message covers the following SCCP messages: long unitdata
service (LUDTS), unitdata service (UDTS), extended unitdata service
(XUDTS).
2.3 Connection Oriented Messages
2.3.1 Connection Oriented Data Transfer
This message transfers data between one SUA to another for connection
oriented service.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0107 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| destination reference number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0003 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0101 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Destination Reference Number Mandatory
Data Mandatory
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
Flags Mandatory *1
Sequence number Mandatory *2
NOTE *1: Mandatory for representing DT1 message.
NOTE *2: Mandatory for protocol class 3;
Optional for protocol class 2.
Implementation note:
This message covers the following SCCP messages: data form 1 (DT1),
data form 2 (DT2), expedited data (ED).
2.3.2 Connection Oriented Data Acknowledge
This message is used to acknowledge receipt of data by the peer.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0107 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| destination reference number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0101 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Destination Reference Number Mandatory
Sequence number Mandatory *1
NOTE *1: Mandatory for protocol class 3;
Optional for protocol class 2.
Implementation note:
This message covers the following SCCP messages: data acknowledgement
(AK), expedited data acknowledgement (EA).
2.3.3 Connect Request
This message is used for establishing a signaling connection between
two peer endpoints. This is used for connection oriented service.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0106 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0103 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
/ Destination Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0102 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Source Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010C | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0003 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Flags Mandatory
Source Reference Number Mandatory
Destination Address Mandatory
Source Address Optional
Credit Optional
Data Optional
2.3.4 Connection Acknowledge
This message is used to acknowledge a connection request between two
peer endpoints.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0107 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0106 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010C | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0103 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Destination Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0003 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Data /
\ \
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Destination Reference Number Mandatory
Source Reference Number Mandatory
Flags Optional
Credit Optional
Destination Address Optional *1
Credit Optional
Data Optional
NOTE *1: Destination Address parameter will be present in case
that the received CORE message conveys the Source Address
parameter.
Implementation note:
This message covers the following SCCP message: connection confirm
(CC).
2.3.5 Connection Refused (COREF)
This message is used to refuse a connection request between two peer
endpoints.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0107 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Reference Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SCCP Error Cause |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0103 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Destination Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0101 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Destination Reference Number Mandatory
SCCP Error Cause Mandatory
Destination Address Optional *1
Data Optional
Note *1: Destination Address parameter will be present in case
that the received CORE message conveys the Source Address
parameter.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
2.3.5 Release Request
This message is used to request a signaling connection between two
peer endpoints be released. All associated resources can then be
released.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0107 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| destination reference number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0106 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| source reference number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0104 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Return Cause |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0003 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Destination Reference Number Mandatory
Source Reference Number Mandatory
Return Cause Mandatory
Flags Optional
Data Optional
Implementation Note:
This message covers the following SCCP message: connection refused
(CREF).
2.3.6 Release Complete
This message is used to acknowledge the release of a signaling
connection between two peer endpoints. All associated resources
should be released.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0107 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| destination reference number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0106 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| source reference number |
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Destination Reference Number Mandatory
Source Reference Number Mandatory
2.3.7 Reset Request
This message is used to indicate that the sending SCCP/SUA wants to
initiate a reset procedure (re-initialization of sequence numbers)
the peer endpoint.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0107 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| destination reference number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0106 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| source reference number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0109 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SCCP Error Cause |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Destination Reference Number Mandatory
Source Reference Number Mandatory
SCCP Error Cause Mandatory
2.3.8 Reset Confirm
This message is used to confirm the Reset Request.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0107 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| destination reference number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0106 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| source reference number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Destination Reference Number Mandatory
Source Reference Number Mandatory
2.3.9 Connection Oriented Error (COERR)
The COERR message is sent when an invalid value is found in an
incoming message.
0 1 2 3
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0107 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| destination reference number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0109 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SCCP Error |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Destination Reference Number Mandatory
SCCP Error Mandatory
Implementation Note: This message covers the following SCCP message:
Protocol data unit error (ERR)
2.4 SS7 Signaling Network Management Messages
2.4.1 Destination Unavailable
The DUNA message is sent from the SG to all concerned ASPs to
indicate that the SG has determined that an SS7 destination is
unreachable. The SUA-User at the ASP is expected to stop traffic to
the affected destination through the SG initiating the DUNA.
The format for DUNA Message parameters is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Affected Point Code /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0001 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Network Appearance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ info string /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Affected Point Code Mandatory
Network Appearance Optional
Info String Optional
2.4.2 Destination Available
The DAVA message is sent from the SG to all concerned ASPs to
indicate that the SG has determined that an SS7 destination is now
reachable. The ASP SUA-User protocol is expected to resume traffic to
the affected destination through the SG initiating the DUNA.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0005 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Affected Point Code /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0005 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Network Appearance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ info string /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Affected Point Code Mandatory
Network Appearance Optional
Info String Optional
2.4.3 Destination State Audit
The DAUD message can be sent from the ASP to the SG to query the
availability state of the SS7 routes to an affected destination. A
DAUD may be sent periodically after the ASP has received a DUNA,
until a DAVA is received. The DAUD can also be sent when an ASP
recovers from isolation from the SG.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0005 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Affected Point Code /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0001 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Network Appearance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ info string /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Affected Point Code Mandatory
Network Appearance Optional
Info String Optional
2.4.4 Destination User Part Unavailable
The DUPU message is used by an SG to inform an ASP that a remote peer
MTP3-User User Part (e.g., ISUP or SCCP) at an SS7 node is
unavailable.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
The format for DUPU Message parameters is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| cause |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0005 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Affected Point Code /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0001 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Network Appearance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ info string /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Cause Mandatory
Affected Point Code Mandatory Note *1
Network Appearance Optional
Info String Optional
The Cause Code parameter indicates the reason that the remote SUA
adaptation layer is unavailable. The valid values for Cause are as
follows:
Value Description
0 Unknown
1 Unequipped Remote User
2 Inaccessible Remote User
Note *1: Affected Point Code can only contain a single affected
point code.
2.4.5 SCCP Management Message
The SCMG message is sent from the between SUA Peers to indicate
status of subsystems. Only one SCMG message type can be sent per
message.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010D | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SCMG Message Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010E | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SMI | Subsystem |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
| Tag = 0x0005 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Affected PC /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0108 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| congestion level |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ INFO String \
\ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
SCMG Message Type Mandatory
Subsystem/SMI Mandatory
Affected Point Code Mandatory *1
Congestion Level Mandatory *2
Info String Optional
Note *1: In the SCMG message, the Affected Point Code Parameter
MUST contain, at most, a single Affected Point Code.
Note *2: When the SCMG Message Type is SSC, then the Congestion
Level parameter is Mandatory, otherwise it is optional.
2.5 Application Server Process Maintenance Messages
2.5.1 ASP Up (ASPUP)
The ASP UP (ASPUP) message is used to indicate to a remote SUA peer
that the Adaptation layer is ready to receive traffic or maintenance
messages.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010A | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASP Capabilities |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0002 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ALI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ info string /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
ASP Capabilities Mandatory
Adaptation Layer Identifier Optional
Info String Optional
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2.5.2 ASP Up Ack (UPACK)
The ASP UP Ack message is used to acknowledge an ASP-Up message
received from a remote SUA peer.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010A | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASP Capabilities |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0002 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ALI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ info string /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
ASP Capabilities Mandatory
Adaptation Layer Identifier Optional
Info String Optional
2.5.3 ASP Down (ASPDN)
The ASP Down (ASPDN) message is used to indicate to a remote SUA peer
that the adaptation layer is not ready to receive traffic or
maintenance messages.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cause Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ info string /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Cause Code Mandatory
Info String Optional
The Cause Code parameter indicates the reason that the remote SUA
adaptation layer is unavailable. The valid values for Reason are
shown in the following table.
Value Description
0x1 Processor Outage
0x2 Management Inhibit
Implementation note:
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
This message covers the following SCCP message: subsystem-prohibited
(SSP).
2.5.4 ASP Down Ack (DNACK)
The ASP DOWN Ack message is used to acknowledge an ASP-Down message
received from a remote SUA peer.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0002 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ALI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ info string /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Adaptation Layer Identifier Optional
Info String Optional
2.5.5 Heartbeat (BEAT)
The Heartbeat message is optionally used to ensure that the SUA peers
are still available to each other. It is recommended for use when
the SUA runs over a transport layer other than the SCTP, which has
its own heartbeat.
The BEAT message contains no parameters.
2.6 ASP Traffic Maintenance Messages
2.6.1 ASP Active (ASPAC)
The ASPAC message is sent by an ASP to indicate to a remote SUA peer
that it is Active and ready to process signaling traffic for a
particular Application Server
The format for the ASPAC message is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ INFO String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
The ASPAC message contains the following parameters:
Type Mandatory
Routing Context Optional
INFO String Optional
Type: 32-bit (unsigned integer)
The Type parameter identifies the traffic mode of operation of the
ASP within an AS. The valid values for Type are shown in the
following table.
1 Over-ride
2 Load-share
Within a particular Routing Context, only one Type can be used. The
Over-ride value indicates that the ASP is operating in Over-ride
mode, where the ASP takes over all traffic in an Application Server
(i.e., primary/back-up operation), over-riding any currently active
ASP in the AS. In Load-share mode, the ASP will share in the traffic
distribution with any other currently active ASPs.
A node that receives an ASPAC with an incorrect Type for a particular
Routing Context will respond with an Error Message (Cause: Invalid
Traffic Handling Mode.
2.6.2 ASP Active Ack
The ASPAC Ack message is used to acknowledge an ASP-Active message
received from a remote SUA peer.
The format for the ASPAC Ack message is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ INFO String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The ASPAC Ack message contains the following parameters:
Type Mandatory
Routing Context Optional
INFO String Optional
Type: 32-bit (unsigned integer)
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
The Type parameter identifies the traffic mode of operation of the
ASP within an AS. The valid values for Type are shown in the
following table.
1 Over-ride
2 Load-share
The type field in the ASPAC Ack message should contain the type as
the ASPAC message to which the message is acknowledging.
2.6.3 ASP Inactive (ASPIA)
The ASPIA message is sent by an ASP to indicate to a remote SUA peer
that it is no longer processing signaling traffic within a particular
Application Server.
The format for the ASPIA message parameters is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ INFO String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The ASPIA message contains the following parameters:
Type Mandatory
Routing Context Optional
INFO String Optional
The Type parameter identifies the traffic mode of operation of the
ASP within an AS. The valid values for Type are shown in the
following table.
Value Description
0x1 Over-ride
0x2 Load-share
Within a particular Routing Context, only one Type can be used. The
Override value indicates that the ASP is operating in Over-ride mode,
and will no longer handle traffic within an Application Server (i.e.,
it is now a backup in a primary/back-up arrangement). The Load-share
value indicates that the ASP is operating in Load-share mode and will
no longer share in the traffic distribution with any other currently
active ASPs.
A node that receives an ASPIA with an incorrect Type for a particular
Routing Context will respond with an Error Message (Cause: Invalid
Traffic Handling Mode.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
2.6.4 ASP Inactive Ack
The ASPIA Ack message is used to acknowledge an ASP-Inactive message
received from a remote SUA peer.
The format for the ASPIA Ack message is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ INFO String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Type Mandatory
Routing Context Optional
INFO String Optional
The Type parameter identifies the traffic mode of operation of the
ASP within an AS. The valid values for Type are shown in the
following table.
1 Over-ride
2 Load-share
The type field in the Ack message should contain the type as the
ASPIA message to which the message is acknowledging.
2.7 Management Messages
These messages are used for managing SUA and the representations of
the SCCP subsystems in the SUA layer.
2.7.1 Error (ERR)
The ERR message is sent between two SUA peers to indicate an error
situation. The Data parameter is option, possibly used for error
logging and/or debugging.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cause |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0003 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ data /
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Cause Mandatory
Data Optional
The Cause parameter can be one of the following values:
Invalid Version 0x1
Invalid Network Appearance 0x2
Invalid Adaptation Layer Identifier 0x3
Invalid Message Type 0x4
Invalid Traffic Handling Mode 0x5
Unexpected Message Type 0x6
Protocol Error 0x7
2.7.2 Audit
This message is used to audit the current state of the peer endpoint.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0005 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Affected Point Code /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0001 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Network Appearance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ info string /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameters
Affected Point Code Mandatory
Network Appearance Optional
Info String Optional
2.7.3 Notify (NTFY)
The Notify message used to provide an autonomous indication of SUA
events to an SUA peer.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010B | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ info string /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The NTFY message contains the following parameters:
Parameters
Status Type Mandatory
Routing Context Optional
Info String Optional
2.8 Common Parameters
These TLV parameters are common across the different adaptation
layers.
Parameter Name Parameter ID
============== ============
Network Appearance 0x0001
Application Layer Identifier 0x0002
Data 0x0003
Info String 0x0004
Affected Point Code 0x0005
Routing Context 0x0006
Diagnostic Info 0x0007
2.8.1 Network Appearance
The Network Appearance parameter identifies the SS7 network context
for the message, for the purposes of logically separating the
signaling traffic between the SG and the Application Server Processes
over common SCTP Associations. An example is where an SG is
logically partitioned to appear as an element in four different
national SS7 networks. A Network Appearance implicitly defines the
SS7 Destination Point Code used, the SS7 Network Indicator value and
SCCP/SCCP-User protocol type/variant/version used within the SS7
network partition. Where an SG operates in the context of a single
SS7 network, or individual SCTP associations are dedicated to each
SS7 network appearance, the Network Appearance parameter is not
required.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0001 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| network appearance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
In an SSNM message, the Network Appearance parameter defines the
format of the Affected PC(s) in the Affected Destination parameter.
The PC point code length (e.g., 14-, 16-, or 24-bit) and sub-field
definitions (e.g., ANSI 24-bit network/cluster/member, ITU-
international 14-bit zone/region/signal_point, many national field
variants, ...) are fixed within a particular Network Appearance.
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Where an SG operates in the context of a single SS7 network, or
individual SCTP associations are dedicated to each SS7 network
context, the Network Appearance parameter is not required and the
format of the Affected PC(s) is understood implicitly.
The format of the Network Appearance parameter is an integer, the
values of which are assigned according to network operator policy.
The values used are of local significance only, coordinated between
the SG and ASP.
Where the optional Network Appearance parameter is present, it must
be the first parameter in the message as it defines the format of the
Affected PCs in the Affected Destination parameter.
2.8.2 Adaptation Layer Identifier
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0002 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ALI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The optional Adaptation Layer Identifier (ALI) is a string that
identifies the adaptation layer. This string MUST be set to "SUA"
which results in a length of 3. The ALI would normally only be used
in the initial ASP Up message across a new SCTP association to ensure
both peers are assuming the same adaptation layer protocol.
2.8.3 Data
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0003 | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2.8.4 Info String
The INFO String parameter can carry any meaningful 8-BIT ASCII
character string along with the message. Length of the INFO String
parameter is from 0 to 255 characters. No procedures are presently
identified for its use but the INFO String may be used by Operators
for debugging purposes.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0004 | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ info string /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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2.8.5 Affected Point Code
The Affected Point Code parameter contains one or more Affected
Destination Point Codes, each a three-octet parameter to allow for 4-
, 16- and 24-bit binary formatted SS7 Point Codes. Affected Point
codes that are less than 24-bits, are padded on the left to the 24-
bit boundary.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0005 | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mask | Affected PC 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ . . . /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The encoding is shown below for ANSI and ITU Point Code examples.
ANSI 24-bit Point Code:
0 1 2 3----
->
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mask | Network | Cluster | Member |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|MSB-----------------------------------------LSB|
ITU 14-bit Point Code:
0 1 2 3----
->
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mask |0 0 0 0 0 0 0 0 0 0|Zone | Region | SP |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|MSB--------------------LSB|
It is optional to send an Affected Pointe Code parameter with more
than one Affected PC but it is mandatory to receive it. All the
Affected PCs included must be within the same Network Appearance.
Including multiple Affected PCs may be useful when reception of an
management message or a linkset event simultaneously affects the
availability status of a list of destinations at an SG.
Mask: 8-bits
The Mask parameter is used to identify a contiguous range of Affected
Destination Point Codes, independent of the point code format.
Identifying a contiguous range of Affected PCs may be useful when
reception of an MTP3 management message or a linkset event
simultaneously affects the availability status of a series of
destinations at an SG.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
The Mask parameter is an integer representing a bit mask that can be
applied to the related Affected PC field. The bit mask identifies
how many bits of the Affected PC field is significant and which are
effectively "wildcarded". For example, a mask of "8" indicates that
the last eight bits of the PC is "wildcarded". For an ANSI 24-bit
Affected PC, this is equivalent to signaling that all PCs in an ANSI
Cluster are unavailable. A mask of "3" indicates that the last three
bits of the PC is "wildcarded". For a 14-bit ITU Affected PC, this
is equivalent to signaling that an ITU Region is unavailable.
2.8.6 Routing Context
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0006 | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Routing Context /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Type parameter identifies the message as an Over-ride or Load-
share Active message. The valid values for Type are shown in the
following table.
Value Description
0x1 Over-ride
0x2 Load-share
Within a particular Routing Context, only one Type can be used.
The optional Routing Context parameter contains (a list of) integers
indexing the Application Server traffic that the sending ASP is
configured to receive. There is one-to-one relationship between an
index entry and an AS Name. Because an AS can only appear in one
Network Appearance, the Network Appearance parameter is not required
in the ASPAC message
An Application Server Process may be configured to process traffic
for more than one logical Application Server. From the perspective
of an ASP, a Routing Context defines a range of signaling traffic
that the ASP is currently configured to receive from the SG.
2.8.7 Diagnostic Information
The Diagnostic Information can be used to convey any information
relevant to an error condition, to assist in the identification of
the error condition. In the case of an Invalid Network Appearance,
Adaptation Layer Identifier or Traffic Handling Mode, the Diagnostic
information includes the received parameter. In the other cases, the
Diagnostic information may be the first 40 bytes of the offending
message.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0007 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Diagnostic Information* /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2.9 SUA-Specific parameters
These TLV parameters are specific to the SUA protocol.
Parameter Name Parameter ID
============== ============
Sequence Number 0x0101
Source Address 0x0102
Destination Address 0x0103
Return Cause 0x0104
Flags 0x0105
Source Reference Number 0x0106
Destination Reference Number 0x0107
Congestion Level 0x0108
SCCP Error 0x0009
ASP Capabilities 0x000A
Status 0x000B
Credit 0x000C
SCMG Message Type 0x000D
SMI / Subsystem 0x000E
2.9.1 Sequence Number
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0101 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This parameter is mapped from the SCCP Sequencing/segmenting
parameter. It is used exclusively for protocol class 3. It is used
to number each DT message sequentially for the purpose of flow
control.
2.9.2 Source Address (=CLG)
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0102 | Parameter Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type of Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Source Address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Type of Address field is used to aid in the identification of the
type of address. If this field is set to 0, then the address field
needs to be analyzed.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
Type of Address
Unknown/Undeterminable 0x00000000
SS7 SCCP CLG 0x00000001
Host Name 0x00000002
IPv4 Address 0x00000003
IPv6 Address 0x00000004
The combinations of SS7 addressing schemes (ITU, ANSI, etc).
supported is implementation dependant.
The Source Address field can contain the SCCP Calling Party Address.
It is possible to simply encapsulate the information, as presented by
the upper layer.
2.9.3 Destination Address (=CLD)
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0103 | Parameter Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type of Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ destination address /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Type of Address field is used to aid in the identification of the
type of address. If this field is set to 0, then the address field
needs to be analyzed.
Type of Address
Unknown/Undeterminable 0x00000000
SS7 SCCP CLD 0x00000001
Host Name 0x00000002
IPv4 Address 0x00000003
IPv6 Address 0x00000004
Note: the combinations of SS7 addressing schemes(ITU, ANSI, etc).
supported is implementation dependant.
The Destination Address field can contain the SCCP Called Party
Address. It is possible to simply encapsulate the information, as
presented by the upper layer.
2.9.4 Return Cause
The Return Cause corresponds to the return cause of the SCCP message.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0104 | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cause Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
The Length is a one octet unsigned integer.
Possible values for the Return Cause are:
0x01 no translation for an address of such nature
0x02 no translation for this specific address
0x03 subsystem congestion
0x04 subsystem failure
0x05 unequipped user
0x06 MTP failure
0x07 network congestion
0x08 unqualified
0x09 error in message transport (Note)
0x0A error in local processing (Note)
0x0B destination cannot perform reassembly (Note)
0x0C SCCP failure
0x0D hop counter violation
0x0E segmentation not supported
0x0F segmentation failure
NOTE: Only applicable to XUDT(S) message.
2.9.5 Flags
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0105 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hop Counter | segmenting |D| B |A| C |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
A Error Return option
Value Description
0x0 No error message
0x1 Return message on error
B Protocol class
Value Description
0x0 Class 0 (connectionless service)
0x1 Class 1 (connectionless service)
0x2 Class 2 (connection-oriented service)
0x3 Class 3 (connection-oriented service
C Importance
Value Description
0x0 Least important
:
0x7 Highest importance
D Segmentation
Value Description
0x0 No segmentation
0x1 Segmentation
Segmenting field corresponds to the SCCP Segmenting parameter.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
0 1 2 3 4 5 6 7 8
+-+-+-+-+-+-+-+-+-+
| segmenting |
+-+-+-+-+-+-+-+-+-+
Bit 8 is coded as the following:
_ 0: in all segments but the first;
_ 1: first segment.
Bit 7 is used to keep in the message in sequence delivery option
required by the SCCP user and is coded as follows:
_ 0: Class 0 selected;
_ 1: Class 1 selected.
Bits 6 and 5 are spare bits.
Bits 4-1 of octet 1 are used to indicate the number of remaining
segments. The values 0000 to 1111 are possible; the value 0000
indicates the last segment.
Hop Counter
Value Description
0x0
:
0x15 Maximum number of GTT
0x16 - 0x255 Spare
2.9.6 Source Reference Number
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0106 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| source reference number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The source reference number is a 3 octet long integer, which is
generated by the local source to identify a connection.
Valid values are from 0x0 to 0xFFFFFE, while 0xFFFFFF is reserved for
future use.
2.9.7 Destination Reference Number
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0107 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| destination reference number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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The Destination Reference Number is a 3 octet long integer, which is
generated by the destination node to identify a connection.
Valid values are from 0x0 to 0xFFFFFE, while 0xFFFFFF is reserved for
future use.
2.9.8 Congestion Level
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0108 | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| congestion level |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The length is one octet.
The valid values for the Congestion Level parameter range from 0 to
7, where 0 indicates least congested and 7 indicates most congested.
2.9.9 SCCP Error
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0109 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| spare | Cause Type | Cause Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Cause Type can have the following values:
Return Cause 0x1
Refusal Cause 0x2
Release Cause 0x3
Reset Cause 0x4
Error Cause 0x5
Cause Value contains the specific error value. Below gives examples
for ITU SCCP values.
Cause value in Correspondence with Reference
SUA message SCCP parameter
------------------ ----------------- ---------
CLDA Return Cause ITU-T Q.713 Chapter 3.12
COREF Refusal Cause ITU-T Q.713 Chapter 3.15
RELRE Release Cause ITU-T Q.713 Chapter 3.11
RESRE Reset Cause ITU-T Q.713 Chapter 3.13
ERR Error Cause ITU-T Q.713 Chapter 3.14
2.9.10 ASP Capabilities
This parameter is used so that the ASP can report it's capabilities
for supporting different protocol classes and interworking scenarios.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
| Tag = 0x010A | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SCCP Variant |0 0 0 0|a|b|c|d| interworking |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The length is two octets.
SCCP Variant field can contain the following values:
Unidentified/unknown 0x0
ITU-I SCCP 0x1
ITU-N SCCP 0x2
ANSI SCCP 0x3
Japanese SCCP 0x4
Chinese SCCP 0x5
Other 0x6
Flags
a - Protocol Class 3
b - Protocol Class 2
c - Protocol Class 1
d - Protocol Class 0
0 indicates no support for the Protocol Class.
Interworking
Values
0x0 indicates no interworking with SS7 Networks.
0x1 indicates IP Signaling Endpoint.
0x2 indicates Signaling Gateway.
2.9.11 Status
The Status Type parameter identifies the type of the status that is
being notified.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010B | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status Type | Status ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The valid values are shown in the following table.
1 Application Server state change (AS_State_Change)
2 Other
The Status Id parameter identifies the status that is being notified.
The valid values are shown in the following table.
If the Status Type is AS_STATE_CHANGE
If the Status Type is AS_State_Change the following Status
Information values are used:
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
1 Application Server Down (AS_Down)
2 Application Server Up (AS_Up)
3 Application Server Active (AS_Active)
4 Application Server Pending (AS_Pending)
5 Alternate ASP Active
6 Insufficient ASPs
If the Status Type is Other, then the following Status Information
values are defined:
1 Insufficient ASP resources active in AS
This notification is not based on the SG reporting the state change
of an ASP or AS. For the value defined the SG is indicating to an
ASP(s) in the AS that another ASP is required in order to handle the
load of the AS.
2.9.12 Credit
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010C | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Credit |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The length is one octet.
2.9.13 SCMG Message Type
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x010D | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SCMG Message Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The SCMG Message Type field may have the following values:
0 Reserved
1 SSA
2 SSP
3 SST
4 SOR
5 SOG
6 SSC
7 - 252 Reserved
253 SNR
254 SBR
255 SRT
2.9.14 SMI / Subsystem
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x000E | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SMI | Spare | SSN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Subsystem Number (SSN) is one octet.
Subsystem multiplicity indicator (SMI) can have the following values:
0x00 Reserved
0x01 Replicated
0x02 Solitary
0x03 Unknown
3 Procedures
The SUA layer needs to respond to various local primitives it
receives from other layers as well as the messages that it receives
from the peer SUA layers. This section describes the SCU procedures
in response to these events.
3.1 Peer Message Procedures
On receiving a message, the SUA layer performs address translation
and mapping (if needed), to determine the appropriate Application
Server Process (ASP). The appropriate ASP can be determined based on
the routing information in the incoming message, local load sharing
information, etc. The appropriate SUA message is then constructed and
sent to the appropriate endpoint, via the correct SCTP association.
3.1.1 Connection Oriented Timers
The SUA layer needs to start a timer after sending a CR, RLSD or RSR
message.
Add more text.
3.2 Signaling Gateway Related Procedures
These support the SUA transport of SCCP-User/SCCP boundary
primitives.
On receiving a SCCP message at the SG, the SUA layer performs address
translation and mapping, to determine the appropriate Application
Server Process (ASP). The appropriate ASP can be determined based on
the information in the incoming message, local load sharing
information, etc. The appropriate SUA message is then constructed and
sent to the appropriate endpoint, via the correct SCTP association.
The SUA needs to setup and maintain the appropriate SCTP association
to the selected endpoint. SUA also manages the usage SCTP streams.
3.2.1 MTP 3 - SUA interaction
The Signaling Gateway will need to manage the availability of the
ASPs within the IP network; while reporting the status of endpoints
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
in the SS7 network. Therefore, there will be interworking between
the MTP 3 layer and SUA. MTP 3 indication messages (MTP Pause, MTP
resume, MPT Status) need to be indicated to the peer SUA layer.
MTP_PAUSE, MTP_STATUS (UPU) and SSP should be mapped on DUNA
messages. It is possible that several ASPs must be informed via DUNA,
depending on the ASs affected.
MTP_RESUME and SSA should be mapped on DAVA messages to the affected
ASPs.
MTP_STATUS (Congestion) and SSC should be mapped on SCON messages to
the affected ASPs.
SST should be mapped on DAUD message to the affected ASPs.
3.3 Layer Management Procedures
The SUA layer needs to send and receive layer management messages.
3.4 SCTP Management Procedures
These procedures support the SUA management of SCTP Associations and
ASP Paths between SGs and ASPs.
3.4.1 State Management
The SUA layer on at each AS needs to maintain the state of each ASP
under its control, as a way to manage the state and connections of
the local ASPs. At a SG, the state of each ASP is needed as input to
the SGs address translation and mapping function.
3.4.1.1 ASP States
The state of each ASP is maintained in the SUA layer at the
controlling AS. The state of an ASP changes due to events. The events
include:
* Reception of messages from that ASP's SUA layer
* Reception of messages from a different ASP's SUA layer
* Reception of indications from the SCTP layer
* Switch over timer triggers
The ASP state transition diagram is shown in Figure 4. The possible
states of an ASP are:
ASP-DOWN: The Application Server Process is unavailable. Initially
all ASPs will be in this state.
ASP-UP: The Application Server Process is available but application
traffic is stopped.
ASP-ACTIVE: The Application Server Process is available and
application traffic is active.
Figure 4: ASP State Transition Diagram
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
+-------------+
| |
+----------------------| ASP-ACTIVE |
| Alternate +-------| |<------------+
| ASP | +-------------+ |
| Takeover | ^ | |
| | ASP | | ASP |
| | Active | | Inactive | ASP
| | | v |Takeover
| | +-------------+ |
| | | |-------------+
| +------>| ASP-UP |-------------+
| +-------------+ |
| ^ | |
ASP Down | ASP | | ASP Down / | ASP
SCTP Down| Up | | SCTP Down | Down/
| | v | SCTP
| +-------------+ | Down
| | | |
+--------------------->| ASP-DOWN |<------------+
| |
+-------------+
Figure 4: ASP State Transition Diagram
SCTP Down: The local SCTP layer's SHUTDOWN COMPLETE notification or
COMMUNICATION LOST notification.
3.4.1.2 AS States
The state of the AS is maintained in the SUA layer.
The state of an AS changes due to events. These events include:
* ASP state transitions
* Recovery timer triggers
The possible states of an AS are:
AS-DOWN: The Application Server is unavailable. This state implies
that all related ASPs are in the ASP-DOWN state for this AS.
Initially the AS will be in this state.
AS-UP: The Application Server is available but no application traffic
is active (i.e., one or more related ASPs are in the ASP-UP state,
but none in the ASP-Active state).
AS-ACTIVE: The Application Server is available and application
traffic is active. This state implies that one ASP is in the ASP-
ACTIVE state.
AS-PENDING: An active ASP has transitioned from active to inactive or
down and it was the last remaining active ASP in the AS. A recovery
timer T(r) will be started and all incoming SCN messages will be
queued by the SG. If an ASP becomes active before T(r) expires, the
AS will move to AS-ACTIVE state and all the queued messages will be
sent to the active ASP.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
If T(r) expires before an ASP becomes active, the SG stops queuing
messages and discards all previously queued messages. The AS will
move to AS-UP if at least one ASP is in ASP-UP state, otherwise it
will move to AS-DOWN state.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
+----------+ one ASP trans to ACTIVE +-------------+
| |---------------------------->| |
| AS-UP | | AS-ACTIVE |
| |<--- | |
+----------+ \ +-------------+
^ | \ Tr Expiry, ^ |
| | \ at least one | |
| | \ ASP in UP | |
| | \ | |
| | \ | |
| | \ | |
one ASP | | all ASP \ one ASP | | Last ACTIVE
trans | | trans to \ trans to | | asp trans
to UP | | DOWN -------\ ACTIVE | | to UP or
| | \ | | DOWN
| | \ | |
| | \ | |
| | \ | |
| v \ | v
+----------+ \ +-------------+
| | --| |
| AS-DOWN | | AS-PENDING |
| | | (queueing) |
| |<----------------------------| |
+----------+ Tr Expiry no ASP +-------------+
in UP state
Tr = Recovery Timer
Figure 5: AS State Transition Diagram
3.4.2 ASPM procedures for primitives
Before the establishment of an SCTP association the ASP state at both
the AS and ASP is assumed to be "Down".
When the SUA layer receives an M-SCTP ESTABLISH request primitive
from the Layer Management, the SUA layer will try to establish an
SCTP association with the remote SUA peer. Upon reception of an
eventual SCTP-Communication Up confirm primitive from the SCTP, the
SUA layer will invoke the primitive M-SCTP ESTABLISH confirm to the
Layer Management.
Alternatively, if the remote SUA-peer establishes the SCTP
association first, the SUA layer will receive an SCTP Communication
Up indication primitive from the SCTP. The SUA layer will then invoke
the primitive M-SCTP ESTABLISH indication to the Layer Management.
Once the SCTP association is established, The SUA layer at an ASP
will then find out the state of its local SUA-user from the Layer
Management using the primitive M-ASP STATUS. Based on the status of
the local SUA-User, the local ASP SUA Application Server Process
Maintenance (ASPM) function will initiate the ASPM procedures, using
the ASP-Up/-Down/-Active/-Inactive messages to convey the ASP-state
to the SG - see Section 3.3.3.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
If the SUA layer subsequently receives an SCTP-Communication Down
indication from the underlying SCTP layer, it will inform the Layer
Management by invoking the M-SCTP STATUS indication primitive. The
state of the ASP will be moved to "Down."
At an ASP, the Layer Management may try to reestablish the SCTP
association using M-SCTP ESTABLISH request primitive.
3.4.3 ASPM procedures for peer-to-peer messages
3.4.3.1 ASP-Up
The AS will mark the path as up if an explicit ASP UP (ASPUP) message
is received and internally the path is allowed to come up (i.e., not
in a locked local maintenance state). An ASP UP (ASPUP) message will
be sent to acknowledge the received ASPUP. The SG will respond to a
ASPUP with a ASPDN message if the path is in a locked maintenance
state.
The receiving ASP will send a ASPUP message in response to a received
ASPUP message from the ASP even if that path was already marked as
UP. The paths are controlled by the ASP.
The ASP will send ASPUP messages every t(a) seconds until the path
comes up (i.e. until it receives a ASPUP message from the remote peer
for that path). The ASP may decide to reduce the frequency (say to
every 5 seconds) if the an acknowledgement is not received after a
few tries.
The ASP should wait for the ASPUP message from the remote peer before
transmitting ASP maintenance messages (ASPIA or ASPAC) or SUA
messages or it will risk message loss.
3.4.3.2 ASP Down
The AS will mark the ASP as down and send a ASPDN message to the ASP
if one of the following events occur:
- an ASP Down(ASPDN) message is received from the ASP,
- the ASP is locked by local maintenance.
The AS will also send a ASPDN message when the ASP is already down
and a ASPDN) message is received from the ASP.
The ASP will send ASPDN whenever it wants to take down a ASP. Since
it is possible for ASPDN messages and responses can be lost (for
example, during a node failover), the ASP can send ASPDN messages
every t(a) seconds until the path comes down (i.e. until it receives
a ASPDN message from the remote peer for that path).
3.4.3.3 ASP Version Control
If a ASP Up message with an unknown version is received, the
receiving end will respond with an Error message. This will indicate
to the sender which version the receiving node supports.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
This is useful when protocol version upgrades are being performed. A
node with the newer version should support the older versions used on
other nodes it is communicating with.
The version field in the Error message header associated will
indicate the version supported by the node.
3.4.3.4 ASP Active
When an ASP Active (ASPAC) message is received, the ASP will start
traffic routing to that ASP. Reception of a ASPAC message overrides
any previous ASPAC messages and results in the ASP associated with
the ASPAC message to become the newly active ASP.
3.4.3.5 ASP Inactive
When a ASPIA message is received, message transmission to that ASP
ceases. The ASP will either discard all incoming messages or start
buffering the incoming messages for T(r)seconds after which messages
will be discarded.
If the ASP is down, all of the Paths that were supported by that ASP
are, by default, down.
4 Examples of SUA Procedures
4.1 Establishment of Association
4.1.1 SG Architecture
SG ASP1 ASP2
(Primary) (Backup)
| | |
<----ASP Up--------+ |
+----ASP Up Ack ---> |
| | |
<-----------------------ASP Up---------+
+-----------------------ASP Up (Ack)--->
| | |
<----ASP Active----+ |
+-ASP Active Ack---> |
| | |
4.1.2 IP to IP Architecture
ASP1 (AS1) ASP1 (AS2) ASP2 (AS2)
(Primary) (Backup)
| | |
<----ASP Up--------+ |
+----ASP Up Ack ---> |
| | |
<-----------------------ASP Up---------+
+-----------------------ASP Up Ack ---->
| | |
<----ASP Active----+ |
+-ASP Active Ack---> |
| | |
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
4.2 ASP fail-over Procedures
SG ASP1 ASP2
| | |
|<-----ASP Inactive-------| |
|---NTFY(ASP Inactive)--->| |
|--------------------NTFY(ASP-Inactive) (Optional)-->|
| | |
|<------------------------------ ASP Active----------|
|-----------------------------NTFY(ASP-Active)------>|
| |
4.3 SUA/SCCP-User Boundary Examples
4.3.1 Data Transfer
This is an example of data transfer, assuming associations are
already established. Note that the SCTP sack is shown purely for
illustrative reasons.
SEP SG SG ASP ASP
SCCP SUA SCTP SCTP SUA
| | | | |
+----UDT-----> | | |
| +---Send----> | |
| |.. . . . . . . CLDT . . . . . . . .>
| | +---data----> |
| | | +-data arr-->
| | | <-rec data--|
| | <---sack----+ |
| <-data arr--+ | |
| +-rec data--> | |
| < . . . . . . . CLDA . . . . . . . ..
| | | | |
5 Security
5.1 Introduction
SUA is designed to carry signaling messages for telephony services.
As such, SUA must involve the security needs of several parties: the
end users of the services; the network providers and the applications
involved. Additional security requirements may come from local
regulation. While having some overlapping security needs, any
security solution should fulfill all of the different parties' needs.
5.2 Threats
There is no quick fix, one-size-fits-all solution for security. As a
transport protocol, SUA has the following security objectives:
* Availability of reliable and timely user data transport.
* Integrity of user data transport.
* Confidentiality of user data.
SUA runs on top of SCTP. SCTP provides certain transport related
security features, such as:
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
* Blind Denial of Service Attacks
* Flooding
* Masquerade
* Improper Monopolization of Services
When SUA is running in professionally managed corporate or service
provider network, it is reasonable to expect that this network
includes an appropriate security policy framework. The "Site Security
Handbook" [2196] should be consulted for guidance.
When the network in which SUA runs in involves more than one party,
it may not be reasonable to expect that all parties have implemented
security in a sufficient manner. End-to-end security should be the
goal, therefore, it is recommended that IPSEC is used to ensure
confidentiality of user payload. Consult [2409] for more information
on configuring IPSEC services.
5.3 Protecting Confidentiality
Particularly for mobile users, the requirement for confidentiality
may include the masking of IP addresses and ports. In this case
application level encryption is not sufficient; IPSEC ESP should be
used instead. Regardless of which level performs the encryption, the
IPSEC ISAKMP service should be used for key management.
6 IANA Considerations
6.1 SCTP Payload Protocol ID
A request will be made to IANA to assign SCTP Payload Protocol IDs.
A Payload ID for the SUA will be registered.
The Payload ID is included in each SCTP data chunk, to indicate which
protocol SCTP is carrying. This Payload ID is not directly used by
SCTP but may be used by certain network entities to identify the type
of information being carried in this DATA chunk.
It is assumed that the Payload ID for SUA will be 3.
6.2 Port Number
SUA will use port number 14001, which is currently registered to
"ITU-T SCCP". This Port Number is the port which the SG listen to
when receiving SCTP datagrams.
7 Timer Values
Ta 2 seconds
Tr 2 seconds
8 Acknowledgements
The authors would like to thank Lode Coene, Joe Keller, Florencio
Escobar-Gonzalez, Marja-Liisa Hamalainen and Markus Maanoja for their
insightful comments and suggestions.
Funding for the RFC editor function is currently provided by the
Internet Society.
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9 Authors' Addresses
John Loughney
Nokia Research Center
PO Box 407
FIN-00045 Nokia Group
Finland
[email protected]
Greg Sidebottom
Nortel Networks
3685 Richmond Rd,
Nepean, Ontario, Canada K2H 5B7
[email protected]
Guy Mousseau
Nortel Networks
3685 Richmond Rd
Nepean, Ontario, Canada K2H 5B7
Stephen Lorusso
Unisphere Solutions
One Executive Drive
Chelmsford, MA 01824
USA
email: [email protected]
10 References
[2719] RFC 2719, "Framework Architecture for Signaling
Transport"
[ITU SCCP] ITU-T Recommendations Q.711-714, 'Signaling System No.
7 (SS7) - Signaling Connection Control Part (SCCP)'
[ANSI SCCP] ANSI T1.112 'Signaling System Number 7 - Signaling
Connection Control Part'
[ITU TCAP] ITU-T Recommendation Q.771-775 'Signaling System No. 7
SS7) - Transaction Capabilities (TCAP)
[ANSI TCAP] ANSI T1.114 'Signaling System Number 7 - Transaction
Capabilities Application Part'
[RANAP] 3G TS 25.413 V3.0.0 (2000-01) 'Technical Specification
3rd Generation Partnership Project; Technical
Specification Group Radio Access Network; UTRAN Iu
Interface RANAP Signalling'
[SCTP] Stream Control Transport Protocol <draft-ietf-sigtran-
sctp-13.txt>, July 2000, Work in Progress.
[M3UA] MTP3-User Adaptation Layer <draft-ietf-sigtran-m3ua-
03.txt>, July 2000, Work in Progress.
[2401] RFC 2401, "Security Architecture for the Internet
Protocol", S. Kent, R. Atkinson, November 1998.
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
[UTRAN IUR] 3G TS 25.420 V3.0.0 (2000-01) "Technical Specification
3rd Generation Partnership Project; Technical
Specification Group Radio Access Network; UTRAN Iur
Interface General Aspects and Principles"
[2196] RFC 2196, "Site Security Handbook", B. Fraser Ed.,
September 1997.
[ENUM] "ENUM Requirements" <draft-ietf-enum-rqmts-01.txt>,
December 1999, Work in Progress.
[E.164-DNS] "E.164 number and DNS", <draft-ietf-enum-e164-dns-
03.txt>, July 2000, Work in Progress.
Appendix A: Message mapping between SCCP and SUA.
This is for illustrative purposes only.
SUA SCCP SCCP Classes Mgt.
SUA
Name Name Full Name 0 1 2 3 Msg. Usage
=====================================================================
Connectionless Messages
CLDT UDT Unitdata X X - - - -
CLDT XUDT Extended unitdata X X - - - -
CLDT LUDT Long unitdata X X - - - -
CLDA UDTS Unitdata service X X - - - -
CLDA XUDTS Extended unitdata serv. X X - - - -
CLDA LUDTS Long unitdata service X X - - - -
Connection-Oriented Messages
CODT DT1 Data form 1 - - X - - -
CODT DT2 Data form 2 - - - X - -
CODT ED Expedited data - - - X - -
CODA AK Data acknowledgement - - - X - -
CODA EA Expedited data ack. - - - X - -
CORE CR Connection request - - X X - -
COAK CC Connection confirm - - X X - -
COAK CREF Connection refused - - X X - -
RELRE RLSD Released - - X X - -
RELCO RLC Release complete - - X X - -
RESRE RSR Reset request - - - X - -
RESCO RSC Reset confirm - - - X - -
General Protocol Messages
ERR ERR Protocol data unit error - - X X - X
AUD IT Inactivity test - - X X - X
SS7 MGT Messages
DUNA n/a n/a - - - - - X
DAVA n/a n/a - - - - - X
DAUD n/a n/a - - - - - X
SCMG SSC SCCP/subsystem-congested - - - - X -
SCMG SSA subsystem-allowed - - - - X -
SCMG SSP subsystem-prohibited - - - - X -
SCMG SST subsystem-status-test - - - - X -
SCMG SOR subsystem-oos-req - - - - X -
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Internet Draft SS7 SCCP-User Adaptation Layer July 2, 2000
SCMG SOG subsystem-oos-grant - - - - X -
SUA MGT Messages
ASPUP n/a n/a - - - - - X
ASPDN n/a n/a - - - - - X
ASPAC n/a n/a - - - - - X
ASPIA n/a n/a - - - - - X
NTFY n/a n/a - - - - - X
- = Message not applicable for this protocol class.
X = Message applicable for this protocol class.
n/a = not applicable
Appendix B: SCTP to SUA Message Mapping Examples
CLDT
- Pointer to Optional part shall be coded as 0 (as long as there
is no optional parameter).
- A and B flags are mapped from 'Protocol Class' parameter
received in XUDT/LUDT/UDT (or from Data Request primitive).
- C flag is mapped from 'Importance parameter' received in XUDT/LUDT
(or from Data Request primitive), or if not present a default
value for the message type shall be used.
Copyright Statement
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This document and translations of it may be copied and furnished to
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or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
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included on all such copies and derivative works. However, this
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HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
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