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Network Working Group Javier Pastor-Balbas
INTERNET-DRAFT Ericsson
Expires: August 2003
Ken Morneault
Cisco Systems
February, 2003
M3UA Implementor's Guide
<draft-ietf-sigtran-m3ua-implementors-guide-03.txt>
Status of this memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
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This document is an individual submission to the IETF. Comments
should be directed to the authors.
Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
This document contains a compilation of all defects found up until
October 2002 for M3UA [RFC3332]. These defects may be of an editorial
or technical nature. This document may be thought of as a companion
document to be used in the implementation of M3UA to clarify errors
in the original M3UA document. This document updates RFC3332 and text
within this document supersedes the text found in RFC3332.
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TABLE OF CONTENTS
1. Introduction.......................................................3
1.1 Abbreviations.....................................................3
2. Conventions........................................................3
3. Corrections to RFC3332.............................................3
3.1 Parameter Containing Subparameters with Padding Bytes..............3
3.2 Dynamic Registration Not Supported.................................4
3.3 Contents of User Protocol Data.....................................6
3.4 NIF Not Available on SGP...........................................7
3.5 Scope of Network Appearance........................................8
3.6 Conditional RC parameter...........................................9
3.7 Receiving REG for a RK already registered.........................12
3.8 Dynamic Registration Support for Alias Point Code.................15
3.9 Auditing procedure and congestion state...........................16
3.10 Response to an ASPIA message.....................................18
3.11 INFO and DIAG parameter length...................................20
3.12 IPSP stuff.......................................................21
3.13 Messages and Streams.............................................28
3.14 ASP Id for IPSP communication....................................28
3.15 n+k redundancy...................................................30
3.16 Multiple Parameters of the Same Type in a Message................34
3.17 Registered Routing Key State After Unexpected ASP Up Message.....34
3.18 Location of Network Appearance...................................35
3.19 Determination of Congestion Abatement When ASP Sends SCON........37
3.20 Removing CIC and SSN from RK.....................................37
3.21 ASP comes to ASP-ACTIVE state without full SS7 connectivity......45
4. Acknowledgements..................................................47
5. Authors' Addresses................................................47
6. References........................................................47
7. Changes Control...................................................47
7.1 Changes from v00 to v01...........................................47
7.2 Changes from v01 to v02...........................................48
7.3 Changes from v02 to v03...........................................48
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1. Introduction
This document contains a compilation of all defects found up until
March 2002 for the MTP3 User Adaptation Layer (M3UA) [RFC3332]. These
defects may be of an editorial or technical nature. This document may
be thought of as a companion document to be used in the
implementation of M3UA to clarify errors in the original M3UA
document. This document updates RFC3332 and text within this
document, where noted, supersedes the text found in RFC3332. Each
error will be detailed within this document in the form of:
- The problem description,
- The text quoted from RFC3332,
- The replacement text,
- A description of the solution.
1.1 Abbreviations
SPC Signalling Point Code
2. Conventions
The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
SHOULD NOT, RECOMMENDED, NOT RECOMMENDED, MAY, and OPTIONAL, when
they appear in this document, are to be interpreted as described in
[RFC2119].
3. Corrections to RFC3332
3.1 Parameter Containing Subparameters with Padding Bytes
3.1.1 Description of the problem
If a parameter contains subparameters with padding bytes, should the
parameter length include the subparameter padding bytes or not.
3.1.2 Text changes to the document
---------
Old text: (Section 3.2)
---------
Parameter Length: 16 bits (unsigned integer)
The Parameter Length field contains the size of the parameter in
bytes, including the Parameter Tag, Parameter Length, and Parameter
Value fields. Thus, a parameter with a zero-length Parameter Value
field would have a Length field of 4. The Parameter Length does not
include any padding bytes.
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---------
New text: (Section 3.2)
---------
Parameter Length: 16 bits (unsigned integer)
The Parameter Length field contains the size of the parameter in
bytes, including the Parameter Tag, Parameter Length, and Parameter
Value fields. Thus, a parameter with a zero-length Parameter Value
field would have a Length field of 4. The Parameter Length does not
include any padding bytes. If the parameter contains subparameters,
the Parameter Length field will include all the bytes of each
subparameter including subparameter padding bytes (if any).
3.1.3 Solution description
When calculating the length of a parameter that contains
subparameters, include the padding bytes of the subparameters.
3.2 Dynamic Registration Not Supported
3.2.1 Description of the problem
There is a need to be able to correlate a Dynamic Registration not
supported error to a Registration Request.
3.2.2 Text changes to the document
---------
Old text: (Section 4.4.1)
---------
If the SGP does not support the registration procedure, the SGP
returns an Error message to the ASP, with an error code of
"Unsupported Message Type".
---------
New text: (Section 4.4.1)
---------
If the SGP does not support the registration procedure, the SGP
returns an Error message to the ASP, with an error code of
"Unsupported Message Class".
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---------
Old text: (Section 3.8.1)
---------
The "Unsupported Message Class" error is sent if a message with an
unexpected or unsupported Message Class is received.
The "Unsupported Message Type" error is sent if a message with an
unexpected or unsupported Message Type is received.
---------
New text: (Section 3.8.1)
---------
The "Unsupported Message Class" error is sent if a message with an
unexpected or unsupported Message Class is received. For this error,
the Diagnostic Information parameter MUST be included with the first
40 bytes of the offending message.
The "Unsupported Message Type" error is sent if a message with an
unexpected or unsupported Message Type is received. For this error,
the Diagnostic Information parameter MUST be included with the first
40 bytes of the offending message.
---------
Old text:
---------
The Error message contains the following parameters:
Error Code Mandatory
Routing Context Mandatory*
Network Appearance Mandatory*
Affected Point Code Mandatory*
Diagnostic Information Optional
(*) Only mandatory for specific Error Codes
---------
New text:
---------
The Error message contains the following parameters:
Error Code Mandatory
Routing Context Mandatory*
Network Appearance Mandatory*
Affected Point Code Mandatory*
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Diagnostic Information Conditional
(*) Only mandatory for specific Error Codes
3.2.3 Solution description
A SGP that does not support registration must return an Error
(Unsupported Message Class) message with the first 40 bytes of the
offending message (i.e. any Routing Key Management message sent by
the ASP) so that the ASP can correlate this error to the Registration
Request message.
Note that the changes to the "Unsupported Message Class" and
"Unsupported Message Type" text make this a general solution that
allows the ASP or SG side to correlate these error responses with the
offending message.
3.3 Contents of User Protocol Data
3.3.1 Description of the problem
There is a need to add a reference that contains the different SS7
message label types to ensure implementations take into account the
differences among these labels.
3.3.2 Text changes to the document
---------
Old text: (Section 3.3.1)
---------
Protocol Data: (variable)
The Protocol Data field contains a byte string of MTP-User
information from the original SS7 message starting with the
first byte of the original SS7 message following the Routing
Label.
---------
New text: (Section 3.3.1)
---------
Protocol Data: (variable)
The Protocol Data field contains a byte string of MTP-User
information from the original SS7 message starting with the
first byte of the original SS7 message following the Routing
Label [7][8][29].
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---------
Old text: (Section 9.1)
---------
[7] ITU-T Recommendations Q.701 to Q.705, "Signalling System No. 7
(SS7) - Message Transfer Part (MTP
---------
New text: (Section 9.1)
---------
[7] ITU-T Recommendations Q.700 to Q.705, "Signalling System No. 7
(SS7) - Message Transfer Part (MTP)"
3.3.3 Solution description
A proper reference was required for the different SS7 message label
types.
3.4 NIF Not Available on SGP
3.4.1 Description of the problem
The text is not clear about how the SGP/SG should handle the case of
the NIF becoming unavailable on a SGP or all SGPs (SG).
3.4.2 Text changes to the document
---------
Old text: (None)
---------
None.
---------
New text: (Section 4.7)
---------
If the SG (all the SGPs) is isolated from the NIF, then all the users
are isolated from the SS7 network. A DUNA(*) message MUST be sent
from the SGPs to all the ASPs.
If only one SGP in the SG is isolated entirely from the NIF, the SGP
SHOULD abort its associations. An alternative would be for the SGP to
send ASP Down Ack.
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If one or more SGP suffer a partial failure (where aborting the
association(s) would cause all active AS(es) to fail), then the SGP
MUST send DUNA messages for the affected SPC(es). This is the case
where an SGP can continue to service one or more active AS(es), but
due to a partial failure it is unable to service other(s) active
AS(es).
3.4.3 Solution description
The addition of this text specifies the SGP/SG behavior for the
different scenarios of the NIF becoming unavailable on the SGP/SG.
3.5 Scope of Network Appearance
3.5.1 Description of the problem
A problem was found with the scope of the NA parameter. It was not
clear whether it should be unique across SG-AS or unique across SCTP
associations
3.5.2 Text changes to the document
---------
Old text: (Section 3.3.1)
---------
Network Appearance: 32-bits (unsigned integer)
The Network Appearance parameter identifies the SS7 network context
for the message and implicitly identifies the SS7 Point Code format
used, the SS7 Network Indicator value, and the MTP3 and possibly the
MTP3-User protocol type/variant/version used within the specific SS7
network. 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.
In other cases the parameter may be configured to be present for the
use of the receiver.
The Network Appearance parameter value is of local significance only,
coordinated between the SGP and ASP. Therefore, in the case where an
ASP is connected to more than one SGP, the same SS7 network context
may be identified by different Network Appearance values depending
over which SGP a message is being transmitted/received.
Where the optional Network Appearance parameter is present, it must
be the first parameter in the message as it defines the format of the
Protocol Data field.
IMPLEMENTATION NOTE: For simplicity of configuration it may be
desirable to use the same NA value across all nodes sharing a
particular network context.
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---------
New text: (Section 3.3.1)
---------
Network Appearance: 32-bits (unsigned integer)
The Network Appearance parameter identifies the SS7 network context
for the message and implicitly identifies the used SS7 Point Code
format, the SS7 Network Indicator value, and the MTP3 and possibly
the MTP3-User protocol type/variant/version used within the specific
SS7 network. Where a 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.
In other cases the parameter may be configured to be present for the
use of the receiver.
The Network Appearance parameter value is of local significance only,
coordinated between the SG and AS. Therefore, in the case where an AS
is connected to more than one SG, the same SS7 network context may be
identified by different Network Appearance values depending over
which SG a message is being transmitted/received.
Where the optional Network Appearance parameter is present, it must
be the first parameter in the message as it defines the format of the
Protocol Data field.
IMPLEMENTATION NOTE: For simplicity of configuration it may be
desirable to use the same NA value across all nodes sharing a
particular network context.
3.5.3 Solution description
The text is modified to show that NA has to be coordinated between AS
to SG. This correction also aligns this text with the NA definition
in section 1.2 of the RFC.
3.6 Conditional RC parameter
3.6.1 Description of the problem
Some optional parameters are not always optional. The text should be
clear when conditionally optional parameters are mandatory.
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3.6.2 Text changes to the document
---------
Old text: (Section 3.3.1)
---------
3.3.1 Payload Data Message (DATA)
The DATA message contains the SS7 MTP3-User protocol data, which is
an MTP-TRANSFER primitive, including the complete MTP3 Routing Label.
The DATA message contains the following variable length parameters:
Network Appearance Optional
Routing Context Optional
Protocol Data Mandatory
Correlation Id Optional
---------
New text: (Section 3.3.1)
---------
3.3.1 Payload Data Message (DATA)
The DATA message contains the SS7 MTP3-User protocol data, which is
an MTP-TRANSFER primitive, including the complete MTP3 Routing Label.
The DATA message contains the following variable length parameters:
Network Appearance Optional
Routing Context Conditional
Protocol Data Mandatory
Correlation Id Optional
---------
Old text: (Section 3.4.1)
---------
Routing Context Optional
---------
New text: (Section 3.4.1)
---------
Routing Context Conditional
---------
Old text: (Section 3.4.2)
---------
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Routing Context Optional
---------
New text: (Section 3.4.2)
---------
Routing Context Conditional
---------
Old text: (Section 3.4.3)
---------
Routing Context Optional
---------
New text: (Section 3.4.3)
---------
Routing Context Conditional
---------
Old text: (Section 3.4.4)
---------
Routing Context Optional
---------
New text: (Section 3.4.4)
---------
Routing Context Conditional
---------
Old text: (Section 3.4.5)
---------
Routing Context Optional
---------
New text: (Section 3.4.5)
---------
Routing Context Conditional
---------
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Old text: (Section 3.4.6)
---------
Routing Context Optional
---------
New text: (Section 3.4.6)
---------
Routing Context Conditional
3.6.3 Solution description
Stating that the parameter is conditional implies that it is not
either optional or mandatory. In the parameter description, the text
explains when Routing Context is mandatory and when optional.
3.7 Receiving REG for a RK already registered
3.7.1 Description of the problem
The RFC does not clearly specify what the SG should do when it
receives a Registration Request for a Routing Key that has already
been registered. There are two scenarios to consider: the
registration request is a duplicate or the registration request
indicates a desire to modify the Routing Key
3.7.2 Text changes to the document
---------
Old text: (Section 3.6.1)
---------
The format of the Routing Key parameter 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local-RK-Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic Mode Type (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Point Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Network Appearance (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Indicators (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Originating Point Code List (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Circuit Range List (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \
/ ... /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Point Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Indicators (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originating Point Code List (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Circuit Range List (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
---------
New text: (Section 3.6.1)
---------
The format of the Routing Key parameter 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local-RK-Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Routing Context (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic Mode Type (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Point Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Network Appearance (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Indicators (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originating Point Code List (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Circuit Range List (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \
/ ... /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Point Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Indicators (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originating Point Code List (optional) |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Circuit Range List (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
---------
Old text: (Section 4.4.1)
---------
Registration Status: 32-bit integer
The Registration Result Status field indicates the success or the
reason for failure of a registration request.
Its values may be:
0 Successfully Registered
1 Error - Unknown
2 Error - Invalid DPC
3 Error - Invalid Network Appearance
4 Error - Invalid Routing Key
5 Error - Permission Denied
6 Error - Cannot Support Unique Routing
7 Error - Routing Key not Currently Provisioned
8 Error - Insufficient Resources
9 Error - Unsupported RK parameter Field
10 Error - Unsupported/Invalid Traffic Handling Mode
---------
New text: (Section 4.4.1)
---------
Registration Status: 32-bit integer
The Registration Result Status field indicates the success or the
reason for failure of a registration request.
Its values may be:
0 Successfully Registered
1 Error - Unknown
2 Error - Invalid DPC
3 Error - Invalid Network Appearance
4 Error - Invalid Routing Key
5 Error - Permission Denied
6 Error - Cannot Support Unique Routing
7 Error - Routing Key not Currently Provisioned
8 Error - Insufficient Resources
9 Error - Unsupported RK parameter Field
10 Error - Unsupported/Invalid Traffic Handling Mode
11 Error - Routing Key Change Refused
---------
Old text: (Section 4.4.1)
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---------
None.
--------
New text: (Section 4.4.1)
---------
If the SGP determines that the received RK was already registered,
the SGP returns a Registration Response message to the ASP,
containing a Registration Result "Error - Cannot Support Unique
Routing". This error applies whether the Routing Key is Active or
Inactive.
An ASP MAY modify an existing Routing Key by including a Routing
Context parameter in the REG REQ. If the SGP determines that the
Routing Context applies to an existing Routing Key, the SG MAY adjust
the existing Routing Key to match the new information provided in the
Routing Key parameter. A Registration Response "ERR - Routing Key
Change Refused" is returned if the SGP does not accept the
modification of the Routing Key due to either it does not support the
re-registration procedure or the specific RC does not exist.
If the change is accepted, a Registration Response "Successfully
Registered" is returned.
3.7.3 Solution description
By specifying the error code and this new text, the cases of
receiving a duplicate registration request or modification to a
Routing Key are resolved.
3.8 Dynamic Registration Support for Alias Point Code
3.8.1 Description of the problem
There is no text regarding the support of an Alias Point Code
configuration in the dynamic registration of Routing Keys.
3.8.2 Text changes to the document
---------
Old text: (Section 3.6.1)
---------
Destination Point Code:
The Destination Point Code parameter is mandatory, and
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Identifies the Destination Point Code of incoming SS7 traffic
for which the ASP is registering. The format is the same as
described for the Affected Destination parameter in the DUNA
message (See Section 3.4.1). Its format is:
---------
New text: (Section 3.6.1)
---------
Destination Point Code:
The Destination Point Code parameter is mandatory, and
Identifies the Destination Point Code of incoming SS7 traffic
for which the ASP is registering. For an alias point code
configuration, the DPC parameter would be repeated for each
point code. The format is the same as described for the
Affected Destination parameter in the DUNA message (See Section
3.4.1). Its format is:
3.8.3 Solution description
The solution was to add some text to describe how an alias point code
configuration could be supported with dynamic registration.
3.9 Auditing procedure and congestion state
3.9.1 Description of the problem
The current description of the AUDIT procedure in regards to
congestion state is not clear enough. When to send SCON is not
completely specified.
3.9.2 Text changes to the document
---------
Old text: (Section 3.3.1)
---------
[...]. Where the SGP maintains the congestion status of the SS7
destination, and the SS7 destination is congested, the SGP MUST
additionally respond with an SCON message before the DAVA or DRST
message. If the SS7 destination is available and congested, the SGP
MUST respond with an SCON message and then a DAVA message. If the
SS7 destination is restricted and congested, the SGP MUST respond
with an SCON message immediately followed by a DRST message. If the
SGP has no information on the availability status of the SS7
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destination, the SGP responds with a DUNA message, as it has no
routing information to allow it to route traffic to this destination.
---------
New text: (Section 3.3.1)
---------
[...]. Where the SGP maintains the congestion status of the SS7
destination, the SGP MUST additionally respond with an SCON message
before the DAVA or DRST message. If the SS7 destination is
available, the SGP MUST respond with an SCON message (indicating the
appropriate congestion level) and then a DAVA message. If the SS7
destination is restricted, the SGP MUST respond with an SCON message
(with the appropriate congestion level) immediately followed by a
DRST message. If the SGP has no information on the availability
status of the SS7 destination, the SGP responds with a DUNA message,
as it has no routing information to allow it to route traffic to this
destination.
Where the SGP does not maintain the congestion status of the SS7
destination, the response to a DAUD message should always be only a
DAVA, DRST or DUNA message as appropriate.
---------
Old text: (Section 5.4)
---------
5.4 M3UA/MTP3-User Boundary Examples
---------
New text: (Section 5.4, 5.5)
---------
5.4 Auditing examples
5.4.1 SG State: Uncongested / Unavailable
ASP SGP
--- ---
| -------- DAUD ---------> |
| <------ SCON(0) -------- |
| <------- DUNA ---------- |
5.4.2 SG state: Congested (Congestion Level=2) / Available
ASP SGP
--- ---
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| -------- DAUD ---------> |
| <------ SCON(2) -------- |
| <------- DAVA ---------- |
5.4.3 SG state: Unknown / Available
ASP SGP
--- ---
| -------- DAUD ---------> |
| <------- DAVA ---------- |
5.4.4 SG state: Uncongested / Unavailable
ASP SGP
--- ---
| -------- DAUD ---------> |
| <------- DUNA ---------- |
5.5 M3UA/MTP3-User Boundary Examples
3.9.3 Solution description
Whenever a DAUD is received, it has to be responded with
DAVA/DUNA/DRST message depending on the peer node's state. If the SGP
has congestion control (i.e. no ITU international networks) an SCON
message with the appropriate congestion level should precede to the
DAVA/DRST messages upon a DAUD arrival.
A new examples section has been added to show this behavior.
3.10 Response to an ASPIA message
3.10.1 Description of the problem
It was not clear how to act in the following scenario:
ASP SGP
--- ---
| ------ ASPIA (RC1)-----> |
| <---- ASPIA Ack ------- |
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| -----DEREG REQ (RC1)---> |
| <----DEREG RSP (RC1)---- |
| -------ASPIA (RC1)-----> |
What should SG do?
3.10.2 Text changes to the document
---------
Old text: (Section 4.5.3)
---------
When an ASP wishes to withdraw from receiving traffic within an AS,
the ASP sends an ASP Inactive message to the SGP or IPSP. This
action MAY be initiated at the ASP by an M-ASP_INACTIVE request
primitive from Layer Management or MAY be initiated automatically by
an M3UA management function. In the case where an ASP is processing
the traffic for more than one Application Server across a common SCTP
association, the ASP Inactive message contains one or more Routing
Contexts to indicate for which Application Servers the ASP Inactive
message applies.
---------
New text: (Section 4.5.3)
---------
When an ASP wishes to withdraw from receiving traffic within an AS,or
the ASP wants to initiate the process of activation, the ASP sends an
ASP Inactive message to the SGP or IPSP.
An ASP Inactive message MUST be always responded by the peer
(although other messages may be sent in the middle):
- If the corresponding RK is registered (statically or
dynamically), the peer should respond with an ASP Inactive Ack
message.
-
If the RK is not registered, or the RC information is not valid,
the peer must respond with an ERROR message with Error Code =
"Invalid Routing Context".
- If the RC is missing and its specification is needed according
to the used configuration, the peer must respond with an ERROR
message with Error Code = "No Configured AS for ASP".
The action of sending the ASP Inactive message MAY be initiated at
the ASP by an M-ASP_INACTIVE request primitive from Layer Management
or MAY be initiated automatically by an M3UA management function. In
the case where an ASP is processing the traffic for more than one
Application Server across a common SCTP association, the ASP Inactive
message contains one or more Routing Contexts to indicate for which
Application Servers the ASP Inactive message applies.
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3.10.3 Solution description
A more detailed specification of the messages to be sent upon the
reception of an ASPIA has been added to the Inactive Procedures
Section.
3.11 INFO and DIAG parameter length
3.11.1 Description of the problem
At the second interop a question was raised about accepting a length
of 4 bytes for DIAG and INFO parameters.
3.11.2 Text changes to the document
---------
Old text: (Section 3.4.1)
---------
INFO String: variable length
The optional INFO String parameter can carry any meaningful UTF-8
[10] character string along with the message. Length of the INFO
String parameter is from 0 to 255 octets. No procedures are presently
identified for its use but the INFO String MAY be used for debugging
purposes.
---------
New text: (Section 3.4.1)
---------
INFO String: variable length
The optional INFO String parameter can carry any meaningful UTF-8
[10] character string along with the message. Length of the INFO
String parameter is from 0 to 255 octets. This means that No
procedures are presently identified for its use but the INFO String
MAY be used for debugging purposes. An INFO String with a zero length
parameter is not considered as an error (this means that the Length
field in the TLV will be set to 4).
---------
Old text: (Section 3.8.1)
---------
Diagnostic Information: variable length
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When included, the optional Diagnostic information can be any
information germane to the error condition, to assist in
identification of the error condition. The Diagnostic information
SHOULD contain the offending message.
---------
New text: (Section 3.8.1)
---------
Diagnostic Information: variable length
When included, the optional Diagnostic information can be any
information germane to the error condition, to assist in
identification of the error condition. The Diagnostic information
SHOULD contain the offending message. TheDiagnostic Information
parameter with a zero length parameter is not considered as an error
(this means that the Length field in the TLV will be set to 4).
3.11.3 Solution description
It has been explicitly included the fact that a parameter with length
zero is allowed.
3.12 IPSP stuff
3.12.1 Description of the problem
At the 2nd M3UA Plugtest several concerns were raised about the non-
interoperability of the two different IPSP exchanges defined in M3UA.
3.12.2 Text changes to the document
---------
Old text: (Section 4.3)
---------
4.3 AS and ASP State Maintenance
The M3UA layer on the SGP maintains the state of each remote ASP, in
each Application Server that the ASP is configured to receive
traffic, as input to the M3UA message distribution function.
Similarly, where IPSPs use M3UA in a point-to-point fashion, the M3UA
layer in an IPSP maintains the state of remote IPSPs. For the
purposes of the following procedures, only the SGP/ASP case is
described but the SGP side of the procedures also apply to an IPSP
sending traffic to an AS consisting of a set of remote IPSPs.
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---------
New text: (Section 4.3)
---------
4.3 AS and ASP/IPSP State Maintenance
The M3UA layer on the SGP maintains the state of each remote ASP, in
each Application Server that the ASP is configured to receive
traffic, as input to the M3UA message distribution function.
Similarly, where IPSPs use M3UA in a point-to-point fashion, the M3UA
layer in an IPSP maintains the state of remote IPSPs.
Two IPSP models are defined with regards to the number of messages
that are needed to a IPSP state change. They are defined as follows:
1- IPSP Single Exchange (SE) model. Only a single exchange of ASPTM
or ASPSM messages is needed to change the IPSP state. This means
that a set of request from one end and acknowledge from the other
will be enough. This configuration requires static RK
configuration.
2- IPSP Double Exchange (DE) model. Both IPSPs have to send request
messages and both IPSPs have to acknowledge the request messages
from the other end. This results in a double exchange of ASPTM and
ASPSM message, one from each end. This configuration supports
dynamic routing key configuration by using RKM messages in the
same way as ASP-SGP scenario.
In order to ensure interoperability, an M3UA implementation
supporting IPSP communication MUST support IPSP SE model and MAY
implement IPSP DE model.
In section 4.3.1: ASP/IPSP States, only the SGP-ASP and the IPSP SE
scenarios are described. For the IPSP DE model, both IPSPs MUST
follow the SGP side of the SGP-ASP procedures.
In section 4.3.2, only the SGP-ASP scenario is described. All of the
procedures referring to an AS served by ASPs are also applicable to
ASes served by IPSPs.
In section 4.3.3, only the Management procedures for the SGP-ASP
scenario are described. The corresponding Management procedures for
IPSPs are directly inferred.
The remaining sections contain specific IPSP Considerations sub-
sections.
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---------
Old text: (Section 4.3.1)
---------
4.3.1 ASP States
The state of each remote ASP, in each AS that it is configured to
operate, is maintained in the M3UA layer in the SGP. The state of a
particular ASP in a particular AS changes due to events. The events
include:
* Reception of messages from the peer M3UA layer at the ASP;
* Reception of some messages from the peer M3UA layer at other ASPs
in the AS (e.g., ASP Active message indicating "Override");
* Reception of indications from the SCTP layer; or
* Local Management intervention.
The ASP state transition diagram is shown in Figure 3. The possible
states of an ASP are:
ASP-DOWN: The remote M3UA peer at the ASP is unavailable and/or the
related SCTP association is down. Initially all ASPs will be in this
state. An ASP in this state SHOULD NOT be sent any M3UA messages,
with the exception of Heartbeat, ASP Down Ack and Error messages.
ASP-INACTIVE: The remote M3UA peer at the ASP is available (and the
related SCTP association is up) but application traffic is stopped.
In this state the ASP SHOULD NOT be sent any DATA or SSNM messages
for the AS for which the ASP is inactive.
ASP-ACTIVE: The remote M3UA peer at the ASP is available and
application traffic is active (for a particular Routing Context or
set of Routing Contexts).
SCTP CDI: The SCTP CDI denotes the local SCTP layer's Communication
Down Indication to the Upper Layer Protocol (M3UA) on an SGP. The
local SCTP layer will send this indication when it detects the loss
of connectivity to the ASP's peer SCTP layer. SCTP CDI is understood
as either a SHUTDOWN_COMPLETE notification or COMMUNICATION_LOST
notification from the SCTP layer.
SCTP RI: The local SCTP layer's Restart indication to the upper layer
protocol (M3UA) on an SG. The local SCTP will send this indication
when it detects a restart from the ASP's peer SCTP layer.
---------
New text: (Section 4.3.1)
---------
4.3.1 ASP States
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The state of each remote ASP/IPSP, in each AS that it is configured
to operate, is maintained in the peer M3UA layer (i.e. in the SGP or
peer IPSP, respectively). The state of a particular ASP/IPSP in a
particular AS changes due to events. The events include:
* Reception of messages from the peer M3UA layer at the ASP/IPSP;
* Reception of some messages from the peer M3UA layer at other
ASPs/IPSPs in the AS (e.g., ASP Active message indicating
"Override");
* Reception of indications from the SCTP layer; or
* Local Management intervention.
The ASP/IPSP state transition diagram is shown in Figure 3. The
possible states of an ASP/IPSP are:
ASP-DOWN: The remote M3UA peer at the ASP/IPSP is unavailable and/or
the related SCTP association is down. Initially all ASPs/IPSPs will
be in this state. An ASP/IPSP in this state SHOULD NOT be sent any
M3UA messages, with the exception of Heartbeat, ASP Down Ack and
Error messages.
ASP-INACTIVE: The remote M3UA peer at the ASP/IPSP is available (and
the related SCTP association is up) but application traffic is
stopped. In this state the ASP/IPSP SHOULD NOT be sent any DATA or
SSNM messages for the AS for which the ASP/IPSP is inactive.
ASP-ACTIVE: The remote M3UA peer at the ASP/IPSP is available and
application traffic is active (for a particular Routing Context or
set of Routing Contexts).
SCTP CDI: The SCTP CDI denotes the local SCTP layer's Communication
Down Indication to the Upper Layer Protocol (M3UA) on an SGP. The
local SCTP layer will send this indication when it detects the loss
of connectivity to the ASP's peer SCTP layer. SCTP CDI is understood
as either a SHUTDOWN_COMPLETE notification or COMMUNICATION_LOST
notification from the SCTP layer.
SCTP RI: The local SCTP layer's Restart indication to the upper layer
protocol (M3UA) on an SG. The local SCTP will send this indication
when it detects a restart from the ASP's/IPSP's peer SCTP layer.
---------
Old text: (Section 4.3.1)
---------
Figure 4: ASP State Transition Diagram, per AS
+--------------+
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| |
+----------------------| ASP-ACTIVE |
| Other +-------| |
| ASP in AS | +--------------+
| Overrides | ^ |
| | ASP | | ASP
| | Active | | Inactive
| | | v
| | +--------------+
| | | |
| +------>| ASP-INACTIVE |
| +--------------+
| ^ |
ASP Down/ | ASP | | ASP Down /
SCTP CDI/ | Up | | SCTP CDI/
SCTP RI | | v SCTP RI
| +--------------+
| | |
+--------------------->| ASP-DOWN |
| |
+--------------+
---------
New text: (Section 4.3.1)
---------
The figure below shows the transitions for the ASP and IPSP cases.
Figure 5: ASP/IPSP State Transition Diagram, per AS
+--------------+
| |
+----------------------| ASP-ACTIVE |
| Other +-------| |
| IPSP in AS | +--------------+
| Overrides | ^ |
| | ASPAC/ | | ASPIA/
| |[ASPAC-Ack]| | [ASPIA-Ack]
| | | v
| | +--------------+
| | | |
| +------>| ASP-INACTIVE |
| | |
| +--------------+
| ^ |
ASPDN/ | | | ASPDN /
[ASPDN-Ack/]| ASPUP/ | | [ASPDN-Ack /]
SCTP CDI/ | [ASPUP-Ack] | | SCTP CDI/
SCTP RI | | | SCTP RI
| | v
| +--------------+
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| | |
+--------------------->| ASP-DOWN |
| |
+--------------+
The transitions in brackets are just valid for the IPSP SE model
communication while the rest are valid for both ASPs and IPSPs.
---------
Old text: (Section 4.3.4.1.2)
---------
Alternatively, an interchange of ASP Up messages from each end can be
performed. This option follows the ASP state transition diagram. It
would need four messages for completion.
---------
New text: (Section 4.3.4.1.2)
---------
Alternatively, when using IPSP DE model, an interchange of ASP Up
messages from each end MUST be performed. Four messages are needed
for completion.
---------
Old text: (Section 4.3.4.3.1)
---------
Alternatively, an interchange of ASP Active messages from each end
can be performed. This option follows the ASP state transition
diagram and gives the additional advantage of selecting a particular
AS to be activated from each end. It is especially useful when an
IPSP is serving more than one AS. It would need four messages for
completion.
---------
New text: (Section 4.3.4.3.1)
---------
Alternatively, when using IPSP DE model, an interchange of ASP Active
messages from each end MUST be performed. Four messages are needed
for completion.
---------
Old text: (Section 4.3.4.4.1)
---------
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Alternatively, an interchange of ASP Inactive messages from each end
can be performed. This option follows the ASP state transition
diagram and gives the additional advantage of selecting a particular
AS to be deactivated from each end. It is especially useful when an
IPSP is serving more than one AS. It would need four messages for
completion.
---------
New text: (Section 4.3.4.4.1)
---------
Alternatively, when using IPSP DE model, an interchange of ASP
Inactive messages from each end MUST be performed. Four messages are
needed for completion.
---------
Old text: (Section 4.4.3)
---------
The Registration/Deregistration procedures work in the IPSP cases in
the same way as in AS-SG cases. An IPSP may register an RK in the
remote IPSP. An IPSP is responsible for deregistering the RKs that
it has registered.
---------
New text: (Section 4.4.3)
---------
The Registration/Deregistration procedures work in the IPSP cases in
the same way as in AS-SG cases. An IPSP may register an RK in the
remote IPSP. An IPSP is responsible for deregistering the RKs that
it has registered.
For the IPSP SE model, it MAY be used one common RK for both IPSP
participating in the communication using the Signaling Point Code
granularity. It would basically consist of <OPC,DPC>. In the case of
RC use, RCs SHOULD be previously agreed between both peers.
3.12.3 Solution description
Text regarding procedures has been modified to explicitely include
IPSP communication. A clear definition of both IPSP models has been
included. Modifications in the ASP state machine have been done to
also include the IPSP model. For interoperability purposes, IPSP SE
model is mandated while DE model is allowed.
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3.13 Messages and Streams
3.13.1 Description of the problem
The relation between messages and what stream to use in order to send
them is diffuse and spread all along the document.
3.13.2 Text changes to the document
---------
Old text: (Section 1.4.7)
---------
None.
---------
New text: (Section 1.4.7)
---------
The following rules MUST to be followed (see section 3.1.2):
1. DATA message is never sent on stream 0.
2. ASPSM, MGMT, RKM classes should be sent on stream 0 (Other than
BEAT, BEAT ACK and NTFY messages)
3. SSNM, ASPTM classes and BEAT, BEAT ACK and NTFY messages can be
sent on any stream.
3.13.3 Solution description
A clear specification of how messages should be sent is included in
the corresponding section.
3.14 ASP Id for IPSP communication
3.14.1 Description of the problem
When using the IPSP communication there is no way to dynamically
exchange the ASP Identifier in both directions.
3.14.2 Text changes to the document
---------
Old text: (Section 3.5.2)
---------
The ASP Up Ack message contains the following parameters:
INFO String (optional)
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The format for ASP Up Ack 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 =0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \
/ INFO String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
---------
New text: (Section 3.5.2)
---------
The ASP Up Ack message contains the following parameters:
ASP Identifier Optional
INFO String Optional
The format for ASP Up Ack 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 = 0x0011 | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASP Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag =0x0004 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \
/ INFO String /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The optional ASP Identifier parameter is specifically useful for IPSP
communication. In that case the IPSP answering the ASP Up message MAY
include its own ASP Identifier value. For AS-SG communication this
parameter MUST NOT be used.
3.14.3 Solution Description
By including the optional ASP Identifier in ASP Up message this can
be achieved. In the AS-SG communication this optional parameter is
not needed
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3.15 n+k redundancy
3.15.1 Description of the problem
The n+k redundancy is explained as a general model to use but there
is no reference in the AS state diagram and sometimes it is not clear
when to use it.
3.15.2 Text changes to the document
---------
Old text: (Section 4.3.2)
---------
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. An Application Server is in
the AS-DOWN state when it is removed from a configuration.
AS-INACTIVE: The Application Server is available but no application
traffic is active (i.e., one or more related ASPs are in the ASP-
INACTIVE state, but none in the ASP-ACTIVE state). The recovery
timer T(r) is not running or has expired.
AS-ACTIVE: The Application Server is available and application
traffic is active. This state implies that at least one ASP is in
the ASP-ACTIVE state.
AS-PENDING: An active ASP has transitioned to ASP-INACTIVE or ASP-
DOWN and it was the last remaining active ASP in the AS. A recovery
timer T(r) SHOULD be started and all incoming signalling messages
SHOULD be queued by the SGP. If an ASP becomes ASP-ACTIVE before T(r)
expires, the AS is moved to the AS-ACTIVE state and all the queued
messages will be sent to the ASP.
If T(r) expires before an ASP becomes ASP-ACTIVE, and the SGP has no
alternative, the SGP may stops queuing messages and discards all
previously queued messages. The AS will move to the AS-INACTIVE state
if at least one ASP is in ASP-INACTIVE state, otherwise it will move
to AS-DOWN state.
Figure 5 shows an example AS state machine for the case where the
AS/ASP data is preconfigured. For other cases where the AS/ASP
configuration data is created dynamically, there would be differences
in the state machine, especially at creation of the AS.
Figure 5: AS State Transition Diagram
+----------+ one ASP trans to ACTIVE +-------------+
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| AS- |---------------------------->| AS- |
| INACTIVE | | ACTIVE |
| |<--- | |
+----------+ \ +-------------+
^ | \ Tr Expiry, ^ |
| | \ at least one | |
| | \ ASP in ASP-INACTIVE | |
| | \ | |
| | \ | |
| | \ | |
one ASP | | all ASP \ one ASP | | Last ACTIVE
trans | | trans to \ trans to | | ASP trans to
to | | ASP-DOWN -------\ ASP- | | ASP-INACTIVE
ASP- | | \ ACTIVE | | or ASP-DOWN
INACTIVE| | \ | | (start Tr)
| | \ | |
| | \ | |
| v \ | v
+----------+ \ +-------------+
| | --| |
| AS-DOWN | | AS-PENDING |
| | | (queueing) |
| |<----------------------------| |
+----------+ Tr Expiry and no ASP +-------------+
in ASP-INACTIVE state)
Tr = Recovery Timer
For example, where the AS/ASP configuration data is not created until
Registration of the first ASP, the AS-INACTIVE state is entered
directly upon the first successful REG REQ from an ASP. Another
example is where the AS/ASP configuration data is not created until
the first ASP successfully enters the ASP-ACTIVE state. In this case
the AS-ACTIVE state is entered directly.
---------
New text: (Section 4.3.2)
---------
AS-DOWN: The Application Server is unavailable. This state implies
that the number of ASPs being in ASP-INACTIVE or ASP-DOWN is less
than "n". Initially the AS will be in this state. An Application
Server is in the AS-DOWN state when it is removed from a
configuration.
AS-INACTIVE: The Application Server is available but no application
traffic is active. This implies that there are at least n ASPs in
either ASP-INACTIVE or ASP-ACTIVE but the total number of ASPs in
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ASP-ACTIVE state has not reach n. The recovery timer T(r) is not
running or has expired.
AS-ACTIVE: The Application Server is available and application
traffic is active. This state implies that at least n ASPs are in
the ASP-ACTIVE state.
AS-PENDING: An active ASP has transitioned from ASP-ACTIVE to ASP-
INACTIVE or ASP-DOWN and it was the number n active ASP in the AS. A
recovery timer T(r) SHOULD be started and all incoming signalling
messages SHOULD be queued by the SGP. If an ASP becomes ASP-ACTIVE
before T(r) expires, the AS is moved to the AS-ACTIVE state and all
the queued messages will be sent to the ASP.
If T(r) expires before an ASP becomes ASP-ACTIVE, and the SGP has no
alternative, the SGP may stops queuing messages and discards all
previously queued messages. The AS will move to the AS-INACTIVE state
if at least the number of ASPs in either ASP-INACTIVE or ASP-ACTIVE
sum n, otherwise it will move to AS-DOWN state.
Figure 5 shows an example AS state machine for the case where the
AS/ASP data is preconfigured and a n+k redundancy model.
Figure 5: AS State Transition Diagram
+----------+ IA2AC +-------------+
| AS- |---------------------------->| AS- |
| INACTIVE | | ACTIVE |
| |<----------- | |
+----------+ \ +-------------+
^ | \ ^ |
| | IA2DN \ PN2IA | | AC2PN
| | \ | |
DN2IA | | \ PN2AC | |
| v \ | v
+----------+ \ +-------------+
| | ----------| |
| AS-DOWN | | AS-PENDING |
| | PN2DN | (queueing) |
| |<----------------------------| |
+----------+ +-------------+
DN2IA: One ASP moves to ASP-INACTIVE causing that n ASPs are in
either ASP-ACTIVE or ASP-INACTIVE states.
IA2DN: One ASP moves to ASP-DOWN causing that the number of ASPs in
either ASP-ACTIVE or ASP-INACTIVE drops below n.
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IA2AC: one ASP moves to ASP-ACTIVE, causing number of ASPs in the
ASP-ACTIVE state to be n.
AC2PN: one ASP in ASP-ACTIVE state moves to ASP-INACTIVE or ASP-DOWN
states, causing the number of ASPs in ASP-ACTIVE drop below n.
PN2AC: One ASP moves to ASP-ACTIVE causing the number of ASPs in the
ASP-ACTIVE state to be n.
PN2IA: T(r) Expiry, n or more ASPs are in either ASP-INACTIVE or ASP-
ACTIVE state and number of ASPs in ASP-ACTIVE state is less than n.
PN2DN: T(r) Expiry, the number of ASPs in either ASP-INACTIVE or ASP-
ACTIVE state is less than n.
For other cases where the AS/ASP configuration data is created
dynamically, there would be differences in the state machine,
especially at creation of the AS. For example, where the AS/ASP
configuration data is not created until Registration of the first
ASP, the AS-INACTIVE state is entered directly upon the nth
successful REG REQ from an ASP belonging to that AS. Another example
is where the AS/ASP configuration data is not created until the nth
ASP successfully enters the ASP-ACTIVE state. In this latter case
the AS-ACTIVE state is entered directly.
---------
Old text: (Section 4.3.4.3, for both loadsharing and broadcast)
---------
An SGP or IPSP, upon reception of an ASP Active message for the first
ASP in a Loadshare AS, MAY choose not to direct traffic to a newly
active ASP until it determines that there are sufficient resources to
handle the expected load (e.g., until there are "n" ASPs in state
ASP-ACTIVE in the AS). In this case, the SGP or IPSP SHOULD withhold
the Notify (AS-ACTIVE) until there are sufficient resources.
---------
New text: (Section 4.3.4.3, for both loadsharing and broadcast)
---------
An SGP or IPSP, upon reception of an ASP Active message for the first
ASP in a Loadshare AS, SHOULD NOT direct traffic to a newly active
ASP until it determines that there are sufficient resources to handle
the expected load (e.g., until there are "n" ASPs in state ASP-ACTIVE
in the AS). In this case, the SGP or IPSP SHOULD withhold the Notify
(AS-ACTIVE) until there are sufficient resources.
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3.15.3 Solution description
The AS state machine reflects the state changes as a function of the
"n" number from the n+k redundancy configuration. This solution is
compliance with the previous one: 1+0 model. The change from MAY to
SHOULD NOT makes it recommendable to send traffic only when the
require ASPs number are in ASP-ACTIVE state.
3.16 Multiple Parameters of the Same Type in a Message
3.16.1 Description of the problem
There was some confusion about whether or not multiple parameters
of same type were allowed in a message.
3.16.2 Text changes to the document
---------
Old text: (Section 3.2)
---------
Where more than one parameter is included in a message, the
parameters may be in any order, except where explicitly mandated. A
receiver SHOULD accept the parameters in any order.
---------
New text: (Section 3.2)
---------
Where more than one parameter is included in a message, the
parameters may be in any order, except where explicitly mandated. A
receiver SHOULD accept the parameters in any order.
Unless explicitly stated or shown in a message format diagram, only
one parameter of the same type is allowed in a message.
3.16.3 Solution Description
Added a statement to clarify that multiple parameters of the same
type are forbidden in messages unless explicitly allowed.
3.17 Registered Routing Key State After Unexpected ASP Up Message
Received
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3.17.1 Description of the problem
If the ASP unexpectedly sends an ASP Up message while in the
ASP-ACTIVE state, it is not clear what the peer should do
with registered Routing Keys. Should these Routing Keys be
maintained as registered or should they be considered
deregistered?
3.17.2 Text changes to the document
---------
Old text: (Section 4.3.4.1)
---------
If an ASP Up message is received and internally the remote ASP is in
the ASP-ACTIVE state, an ASP Up Ack message is returned, as well as
an Error message ("Unexpected Message), and the remote ASP state is
changed to ASP-INACTIVE in all relevant Application Servers.
---------
New text: (Section 4.3.4.1)
---------
If an ASP Up message is received and internally the remote ASP is in
the ASP-ACTIVE state, an ASP Up Ack message is returned, as well as,
an Error message ("Unexpected Message). In addition, the remote ASP
state is changed to ASP-INACTIVE in all relevant Application Servers
and all registered Routing Keys are considered deregistered.
3.17.3 Solution Description
Added a statement to clarify that registered Routing Keys will be
considered deregistered if an unexpected ASP Up message is received
while the ASP is in the ASP-ACTIVE state. This clarification ensures
the two peers remain synchronized.
3.18 Location of Network Appearance
3.18.1 Description of the problem
For the Payload Data message, it is clear that the Network
Appearance, if included, MUST be the first parameter in the message.
For the other messages that may contain Network Appearance, it is not
so clear.
3.18.2 Text changes to the document
Pastor, Morneault [Page 35]
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---------
Old text: (Section 3.4.1)
---------
Network Appearance: 32-bit unsigned integer
See Section 3.3.1
---------
New text: (Section 3.4.1)
---------
Network Appearance: 32-bit unsigned integer
The description of Network Appearance in Section 3.3.1 applies
with the exception that Network Appearance does not have to be
the first parameter in this message.
---------
Old text: (Section 3.6.1)
---------
Network Appearance:
The optional Network Appearance parameter field identifies the SS7
network context for the Routing Key, and has the same format as in
the DATA message (See Section 3.3.1). The absence of the Network
Appearance parameter in the Routing Key indicates the use of any
Network Appearance value. Its format is:
---------
New text: (Section 3.6.1)
---------
Network Appearance:
The optional Network Appearance parameter field identifies the SS7
network context for the Routing Key, and has the same format as in
the DATA message (See Section 3.3.1) with the exception that it
does not have to be the first parameter in the message. The
absence of the Network Appearance parameter in the Routing Key
indicates the use of any Network Appearance value. Its format is:
3.18.3 Solution Description
Add statements to clarify that Network Appearance, if present, does
not have to be the first parameter in the message with the exception
of the Payload Data message.
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3.19 Determination of Congestion Abatement When ASP Sends SCON
3.19.1 Description of the problem
Currently, there is no text in the RFC indicating that the ASP
indicates when congestion has abated.
3.19.2 Text changes to the document
---------
Old text: (Section 3.4.4)
---------
The SCON message can be sent from an SGP to all concerned ASPs to
indicate that an SG has determined that there is congestion in the
SS7 network to one or more destinations, or to an ASP in response to
a DATA or DAUD message as appropriate. For some MTP protocol
variants (e.g., ANSI MTP) the SCON message may be sent when the SS7
congestion level changes. The SCON message MAY also be sent from the
M3UA layer of an ASP to an M3UA peer indicating that the M3UA layer
or the ASP is congested.
---------
New text: (Section 3.4.1)
---------
The SCON message can be sent from an SGP to all concerned ASPs to
indicate that an SG has determined that there is congestion in the
SS7 network to one or more destinations, or to an ASP in response to
a DATA or DAUD message as appropriate. For some MTP protocol
variants (e.g., ANSI MTP) the SCON message may be sent when the SS7
congestion level changes. The SCON message MAY also be sent from the
M3UA layer of an ASP to an M3UA peer indicating that the congestion
level of the M3UA layer or the ASP has changed.
3.19.3 Solution Description
Clarify that the ASP needs to indicate when the congestion level has
changed (including abatement). Further, the ASP peer can maintain
a timer, if desired, in case the ASP fails to indicate congestion
abatement.
3.20 Removing CIC and SSN from RK
3.20.1 Description of the problem
Use of SSN and CIC Routing Keys is inadequately defined in RFC3332
leading to non-interoperable solutions.
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3.20.2 Text changes to the document
---------
Old text: (Section 1.4.2.1)
---------
Possible SS7 address/routing information that comprise a Routing Key
entry includes, for example, the OPC, DPC, SIO found in the MTP3
routing label, or MTP3-User specific fields (such as the ISUP CIC,
SCCP subsystem number). Some example Routing Keys are: the DPC
alone, the DPC/OPC combination, the DPC/OPC/CIC combination, or the
DPC/SSN combination. The particular information used to define an
M3UA Routing Key is application and network dependent, and none of
the above examples are mandated.
---------
New text: (Section 1.4.2.1)
---------
Possible SS7 address/routing information that comprise a Routing Key
entry includes, for example, the OPC, DPC, SIO found in the MTP3
routing label. Some example Routing Keys are: the DPC alone, the
DPC/OPC combination, or the DPC/OPC/SI combination. The particular
information used to define an M3UA Routing Key is application and
network dependent, and none of the above examples are mandated.
---------
Old text: (Section 1.4.2.2)
---------
Routing Keys SHOULD be unique in the sense that each received SS7
signalling message SHOULD have a full or partial match to a single
routing result. It is not necessary for the parameter range values
within a particular Routing Key to be contiguous. For example, an AS
should be configured to support call processing for multiple ranges
of PSTN trunks that are not represented by contiguous CIC values.
---------
New text: (Section 1.4.2.2)
---------
Routing Keys SHOULD be unique in the sense that each received SS7
signalling message SHOULD have a full or partial match to a single
routing result. It is not necessary for the parameter range values
within a particular Routing Key to be contiguous.
---------
Old text: (Section 1.4.7)
---------
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The M3UA layer at both the SGP and ASP also supports the assignment
of signalling traffic into streams within an SCTP association.
Traffic that requires sequencing SHOULD be assigned to the same
stream. To accomplish this, MTP3-User traffic may be assigned to
individual streams based on, for example, the SLS value in the MTP3
Routing Label or the ISUP CIC assignment, subject of course to the
maximum number of streams supported by the underlying SCTP
association.
---------
New text: (Section 1.4.7)
---------
The M3UA layer at both the SGP and ASP also supports the assignment
of signalling traffic into streams within an SCTP association.
Traffic that requires sequencing SHOULD be assigned to the same
stream. To accomplish this, MTP3-User traffic may be assigned to
individual streams based on, for example, the SLS value in the MTP3
Routing Label, subject of course to the maximum number of streams
supported by the underlying SCTP association.
---------
Old text: (Section 1.5.3)
---------
In this example, the SGP contains an instance of the SS7 SCCP
protocol layer that may, for example, perform the SCCP Global Title
Translation (GTT) function for messages logically addressed to the SG
SCCP. If the result of a GTT for an SCCP message yields an SS7 DPC
or DPC/SSN address of an SCCP peer located in the IP domain, the
resulting MTP-TRANSFER request primitive is sent to the local M3UA-
resident network address translation and mapping function for ongoing
routing to the final IP destination.
---------
New text: (Section 1.5.3)
---------
In this example, the SGP contains an instance of the SS7 SCCP
protocol layer that may, for example, perform the SCCP Global Title
Translation (GTT) function for messages logically addressed to the SG
SCCP. If the result of a GTT for an SCCP message yields an SS7 DPC
or DPC/SI address of an SCCP peer located in the IP domain, the
resulting MTP-TRANSFER request primitive is sent to the local M3UA-
resident network address translation and mapping function for ongoing
routing to the final IP destination.
---------
Old text: (Section 1.5.3)
---------
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For internal SGP modeling purposes, this may be accomplished with the
use of an implementation-dependent nodal interworking function within
the SGP that effectively sits below the SCCP and routes MTP-TRANSFER
request/indication messages to/from both the MTP3 and the M3UA layer,
based on the SS7 DPC or DPC/SSN address information. This nodal
interworking function has no visible peer protocol with either the
ASP or SEP.
---------
New text: (Section 1.5.3)
---------
For internal SGP modeling purposes, this may be accomplished with the
use of an implementation-dependent nodal interworking function within
the SGP that effectively sits below the SCCP and routes MTP-TRANSFER
request/indication messages to/from both the MTP3 and the M3UA layer,
based on the SS7 DPC or DPC/SI address information. This nodal
interworking function has no visible peer protocol with either the
ASP or SEP.
---------
Old text: (Section 3.2)
---------
Congestion Indications 0x0205
Concerned Destination 0x0206
Routing Key 0x0207
Registration Result 0x0208
Deregistration Result 0x0209
Local_Routing Key Identifier 0x020a
Destination Point Code 0x020b
Service Indicators 0x020c
Reserved 0x020d
Originating Point Code List 0x020e
Circuit Range 0x020f
Protocol Data 0x0210
Reserved 0x0211
Registration Status 0x0212
Deregistration Status 0x0213
---------
New text: (Section 3.2)
---------
Congestion Indications 0x0205
Concerned Destination 0x0206
Routing Key 0x0207
Registration Result 0x0208
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Deregistration Result 0x0209
Local_Routing Key Identifier 0x020a
Destination Point Code 0x020b
Service Indicators 0x020c
Reserved 0x020d
Originating Point Code List 0x020e
Protocol Data 0x0210
Reserved 0x0211
Registration Status 0x0212
Deregistration Status 0x0213
---------
Old text: (Section 3.6.1)
---------
| Traffic Mode Type (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Point Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Network Appearance (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Indicators (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originating Point Code List (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Circuit Range List (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \
/ ... /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Point Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Indicators (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originating Point Code List (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Circuit Range List (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Note: The Destination Point Code, Service Indicators, Originating
Point Code List and Circuit Range List parameters MAY be repeated
as a grouping within the Routing Key parameter, in the structure
shown above.
---------
New text: (Section 3.6.1)
---------
| Traffic Mode Type (optional) |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Point Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Network Appearance (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Indicators (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originating Point Code List (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \
/ ... /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Point Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Service Indicators (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Originating Point Code List (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Note: The Destination Point Code, Service Indicators, and
Originating Point Code List parameters MAY be repeated as a
grouping within the Routing Key parameter, in the structure shown
above.
---------
Old text: (Section 3.6.1)
---------
Circuit Range:
An ISUP controlled circuit is uniquely identified by the SS7 OPC,
DPC and CIC value. For the purposes of identifying Circuit Ranges
in an M3UA Routing Key, the optional Circuit Range parameter
includes one or more circuit ranges, each identified by an OPC and
Upper/Lower CIC value. The DPC is implicit as it is mandatory and
already included in the DPC parameter of the Routing Key. The
absence of the Circuit Range parameter in the Routing Key
indicates the use of any Circuit Range values, in the case of
ISUP/TUP traffic. The Origination Point Code is encoded the same
as the Destination Point Code parameter, while the CIC values are
16-bit integers.
---------
New text: (Section 3.6.1)
---------
(none)
---------
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Old text: (Section 3.6.1)
---------
The Circuit Range format 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 = 0x020f | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mask = 0 | Origination Point Code #1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Lower CIC Value #1 | Upper CIC Value #1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mask = 0 | Origination Point Code #2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Lower CIC Value #2 | Upper CIC Value #2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ ... /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mask = 0 | Origination Point Code #n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Lower CIC Value #n | Upper CIC Value #n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
---------
New text: (Section 3.6.1)
---------
(none)
---------
Old text: (Section 3.7.1)
---------
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
signalling traffic that the ASP is currently configured to receive
from the SGP. For example, an ASP could be configured to support
call processing for multiple ranges of PSTN trunks and therefore
receive related signalling traffic, identified by separate SS7
DPC/OPC/CIC ranges.
---------
New text: (Section 3.7.1)
---------
Pastor, Morneault [Page 43]
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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
signalling traffic that the ASP is currently configured to receive
from the SGP. For example, an ASP could be configured to support
call processing for multiple ranges of PSTN trunks and therefore
receive related signalling traffic, identified by separate SS7
DPC/OPC/SI ranges.
---------
Old text: (Section 4.4.1)
---------
If an SGP determines that one or more of the Routing Key parameters
are not supported for the purpose of creating new Routing Key
entries, the SGP returns a Registration Response message to the ASP,
containing a Registration Result "Error - Unsupported RK parameter
field". This result MAY be used if, for example, the SGP does not
support RK Circuit Range Lists in a Routing Key because the SGP does
not support ISUP traffic, or does not provide CIC range granularity.
---------
New text: (Section 4.4.1)
---------
If an SGP determines that one or more of the Routing Key parameters
are not supported for the purpose of creating new Routing Key
entries, the SGP returns a Registration Response message to the ASP,
containing a Registration Result "Error - Unsupported RK parameter
field".
---------
Old text: (Section A.2.1)
---------
For example, where Application Servers are defined using ranges of
ISUP CIC values, the Operator is implicitly splitting up control of
the related circuit groups. Some CIC value range assignments may
interfere with ISUP circuit group management procedures.
---------
New text: (Section A.2.1)
---------
(none)
Pastor, Morneault [Page 44]
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3.20.3 Solution Description
The removal of reference to SSN and CIC used in Routing Keys as well
as removal of Circuit Range from the Routing Key parameter removes
the unclear text from the specification.
3.21 ASP comes to ASP-ACTIVE state without full SS7 connectivity
3.21.1 Description of the problem
There is not explicit text explaining how the protocol should work
for the case when an ASP comes to ASP-ACTIVE state and there exist
some problems in the SS7 network that prevent it to have full
connectivity.
3.21.2 Text changes to the document
---------
Old text: (Section 4.5.1)
---------
The SGP M3UA layer determines the set of concerned ASPs to be
informed based on the specific SS7 network for which the primitive
indication is relevant. In this way, all ASPs configured to
send/receive traffic within a particular network appearance are
informed. If the SGP operates within a single SS7 network
appearance, then all ASPs are informed.
DUNA, DAVA, SCON, and DRST messages may be sent sequentially and
processed at the receiver in the order sent.
---------
New text: (Section 4.5.1)
---------
The SGP M3UA layer determines the set of concerned ASPs to be
informed based on the specific SS7 network for which the primitive
indication is relevant. In this way, all ASPs configured to
send/receive traffic within a particular network appearance are
informed. If the SGP operates within a single SS7 network
appearance, then all ASPs are informed.
Pastor, Morneault [Page 45]
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For the particular case that an ASP becomes active for an AS and
destinations normally accessible to the AS are inaccessible,
restricted or congested, the SG MAY send DUNA, DRST or SCON messages
for the inaccessible, restricted or congested destinations to the ASP
newly active for the AS to prevent the ASP from sending traffic for
destinations that it might otherwise not know that are inaccessible,
restricted or congested.
DUNA, DAVA, SCON, and DRST messages may be sent sequentially and
processed at the receiver in the order sent.
---------
Old text: (Section 4.6)
---------
The ASP MAY choose to audit the availability of unavailable
destinations by sending DAUD messages. This would be for example the
case when an AS becomes active at an ASP and does not have current
destination statuses. If MTP restart is in progress at the SG, the
SGP returns a DUNA message for that destination, even if it received
an indication that the destination became available or restricted.
In the IPSP case, MTP restart could be considered if the IPSP also
has connection to an SS7 network. [...]
---------
New text: (Section 4.6)
---------
The ASP MAY choose to audit the availability of unavailable
destinations by sending DAUD messages. This would be for example the
case when an AS becomes active at an ASP and does not have current
destination statuses. If MTP restart is in progress at the SG, the
SGP returns a DUNA message for that destination, even if it received
an indication that the destination became available or restricted.
When an ASP becomes active for an AS and the SG is experiencing SS7
network isolation or is performing the MTP Restart procedure for the
AS, the SG SHOULD send a DUNA(*) to the newly active ASP to prevent
the ASP from sending traffic.
In the IPSP case, MTP restart could be considered if the IPSP also
has connection to an SS7 network. [...]
3.21.3 Solution Description
Pastor, Morneault [Page 46]
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By specifying how send SSNM messages in that scenario the problem is
solved.
4. Acknowledgements
The authors would like to thank Lyndon Ong, Tolga Asveren, Brian
Bidulock, Umesh Vats, Barry Nagelberg and many others for their
valuable comments and suggestions.
5. Authors' Addresses
Javier Pastor-Balbas
Ericsson Espana S.A.
Ombu 3
28045 Madrid
Spain
Phone: +34-91-339-3819
Email: [email protected]
Ken Morneault
Cisco Systems Inc.
13615 Dulles Technology Drive
Herndon, VA. 20171
USA
Phone: +1-703-484-3323
EMail: [email protected]
6. References
[RFC3332] "Signaling System 7 (SS7) Message Transfer Part 3 (MTP3) -
User Adaptation Layer (M3UA)". G. Sidebotton, K.
Morneault, J. Pastor-Balbas.
7. Changes Control
7.1 Changes from v00 to v01
- Typos.
- Update all the RC references to show it is a semi-optional
parameter.
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- DUNA(*) substituted for ASPIA-ACK when NIF is not available.
- New sections added:
- IPSP stuff
- Messages and Streams
- ASP Id for IPSP communication
- n+k redundancy
7.2 Changes from v01 to v02
- ASPIA-ACK substituted for DUNA when NIF is not available since
it also allows inter-ASP routing.
- Changed REGREQ's parameter from "Origination Point Code" to
"Destination Point Code".
7.3 Changes from v02 to v03
- Changed from "semi-optional" to "conditional"- Section 3.7 reworded
- Updated Section 3.8 to correctly explain how the alias point code
configuration can be supported with dynamically registered Routing
Keys
- Changes in "messages and streams" section
- IPSP DE model is allowed. But IPSP MUST be supported.
- New sections added:
- Multiple Parameters of the Same Type in a Message
- Registration Routing Key State After Unexpected ASP Up Message
- Location of Network Appearance
- Determination of Congestion Abatement When ASP Sends SCON
- Removing CIC and SSN from RK
- ASP comes to ASP-ACTIVE state without full SS7 connectivity
Full Copyright Statement
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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
Pastor, Morneault [Page 48]
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kind, provided that the above copyright notice and this paragraph are
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Acknowledgment
Funding for the RFC Editor function is currently provided by the
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Pastor, Morneault [Page 49]
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