| draft-ietf-sigtran-m2ua-15 Description: Request For Comments
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Network Working Group Ken Morneault
INTERNET-DRAFT Cisco Systems
Ram Dantu
NetRake
Greg Sidebottom
gregside consulting
Tom George
Alcatel
Brian Bidulock
OpenSS7
Jacob Heitz
Lucent
Expires in June 2002 Feb 2002
Signaling System 7 (SS7) Message Transfer Part (MTP) 2 -
User Adaptation Layer
<draft-ietf-sigtran-m2ua-15.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
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Abstract
This Internet Draft defines a protocol for backhauling of SS7 MTP2
User signalling messages over IP using the Stream Control
Transmission Protocol (SCTP). This protocol would be used between a
Signalling Gateway (SG) and Media Gateway Controller (MGC). It is
assumed that the SG receives SS7 signalling over a standard SS7
interface using the SS7 Message Transfer Part (MTP) to provide
transport. The Signalling Gateway would act as a Signalling Link
Terminal.
Morneault, et al [Page 1]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
TABLE OF CONTENTS
1. Introduction..............................................3
1.1 Scope..................................................3
1.2 Terminology............................................3
1.3 Signalling Transport Architecture......................5
1.4 Services Provide by the M2UA Adaptation Layer..........7
1.5 Function Provided by the M2UA Layer....................9
1.6 Definition of the M2UA Boundaries.....................11
2. Conventions..............................................13
3. Protocol Elements........................................13
3.1 Common Message Header.................................13
3.2 M2UA Message Header...................................17
3.3 M2UA Messages.........................................18
4. Procedures...............................................48
4.1 Procedures to Support the M2UA-User Layer.............49
4.2 Receipt of Primitives from the Layer Management.......49
4.3 AS and ASP State Maintenance..........................51
4.4 Link Key Management Procedures........................62
5. Examples of MTP2 User Adaptation (M2UA) Procedures.......63
5.1 Establishment of associations between SG and MGC......63
examples
5.2 MTP Level 2 / MTP Level 3 Boundary Examples...........66
5.3 Layer Management Communication Examples...............66
6. Timers...................................................71
7. Security Considerations..................................71
7.1 Threats................................................71
7.2 Protecting Confidentiality.............................72
8. IANA Considerations......................................72
8.1 SCTP Payload Protocol Identifier.......................72
8.2 IUA Protocol Extensions................................72
9. Acknowledgements.........................................74
10. References...............................................74
11. Author's Addresses.......................................75
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Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
1. Introduction
This draft defines a protocol for the backhauling of SS7 [1] MTP2 User
[2] [3] [4] (i.e. MTP3) signalling messages over IP using the Stream Control
Transmission Protocol (SCTP) [8]. This protocol would be used between
a Signalling Gateway (SG) and Media Gateway Controller (MGC).
1.1 Scope
There is a need for Switched Circuit Network (SCN) signalling protocol
delivery from an Signalling Gateway (SG) to a Media Gateway
Controller (MGC) [9]. The delivery mechanism addresses the following
objectives:
* Support for MTP Level 2 / MTP Level 3 interface boundary
* Support for communication between Layer Management modules on SG
and MGC
* Support for management of SCTP active associations between the SG and
MGC
The SG will terminate up to MTP Level 2 and the MGC will terminate
MTP Level 3 and above. In other words, the SG will transport MTP
Level 3 messages over an IP network to a MGC.
1.2 Terminology
Application Server (AS) - A logical entity serving a specific application
instance. An example of an Application Server is a MGC handling the
MTP Level 3 and call processing for SS7 links terminated by the
Signalling Gateways. Practically speaking, an AS is modeled at the SG
as an ordered list of one or more related Application Server Processes
(e.g., primary, secondary, tertiary, ...).
Application Server Process (ASP) - A process instance of an Application
Server. Examples of Application Server Processes are active or standby
MGC instances.
Association - An association refers to a SCTP association. The
association will provide the transport for the delivery of protocol
data units for one or more interfaces.
Backhaul - Refers to the transport of signalling from the point of
interface for the associated data stream (i.e., SG function in the MGU)
back to the point of call processing (i.e., the MGCU), if this is not
local [9].
Fail-over - The capability to reroute signalling traffic as required
to an alternate Application Server Process 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.
Host - The computing platform that the ASP process is running on.
Interface - For the purposes of this document, an interface is a SS7
signalling link.
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Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
Interface Identifier - The Interface Identifier identifies the physical
interface at the SG for which the signalling messages are sent/received.
The format of the Interface Identifier parameter can be text or 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.
Layer Management - Layer Management is a nodal function in an SG or
ASP that handles the inputs and outputs between the M2UA layer and a
local management entity.
Link Key - The link key is a locally unique (between ASP and SG)
value that identifies a registration request for a particular
Signalling Data Link and Signalling Terminal pair.
MTP - The Message Transfer Part of the SS7 protocol
MTP2 - MTP Level 2, the signalling datalink layer of SS7
MTP3 - MTP Level 3, the signalling network layer of SS7
MTP2-User - A protocol that uses the services of MTP Level 2
(i.e. MTP3).
Network Byte Order: Most significant byte first, a.k.a Big Endian.
Signalling Data Link - An SDL refers to a specific communications
facility that connects two Signalling Link Terminals.
Signalling Gateway (SG) - An SG is a signalling agent at the edge of
the IP network. An SG appears to the SS7 as one or more Signalling
Link Terminals that are connected to one or more Signalling Data Links
in the SS7 network. An SG contains a set of one or more unique
Signalling Gateway Processes, on which one or more is normally
actively processing traffic. Where an SG contains more than one SGP,
the SG is a logical entity.
Signalling Gateway Process (SGP) - A process instance that uses M2UA to
communicate to and from a Signalling Link Terminal. It serves as an
active, backup or load-sharing proces of a Signalling Gateway.
Signalling Link Terminal (SLT) - Refers to the means of performing all
of the functions defined at MTP level 2 regardless of their
implementation [2].
Stream - A stream refers to an SCTP stream; a unidirectional 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 unordered delivery service.
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1.3 M2UA Overview
The framework architecture that has been defined for SCN signalling
transport over IP [9] uses two components: a signalling common
transport protocol and an adaptation module to support the services
expected by a particular SCN signalling protocol from its underlying
protocol layer.
Within this framework architecture, this document defines a SCN
adaptation module that is suitable for the transport of SS7 MTP2 User
messages. The only SS7 MTP2 User is MTP3. The M2UA uses the services
of the Stream Control Transmission Protocol [8] as the underlying
reliable signalling common transport protocol.
In a Signalling Gateway, it is expected that the SS7 MTP2-User signalling
is transmitted and received from the PSTN over a standard SS7 network
interface, using the SS7 Message Transfer Part Level 1 and Level 2 [3,4]
to provide reliable transport of the MTP3-User signalling messages to and
from an SS7 Signalling End Point (SEP) or Signalling Transfer Point (STP).
The SG then provides a interworking of transport functions
with the IP transport, in order to transfer the MTP2-User signalling
messages to and from an Application Server Process where the peer MTP2-
User protocol layer exists.
1.3.1 Example - SG to MGC
In a Signalling Gateway, it is expected that the SS7 signalling is
received over a standard SS7 network termination, using the SS7 Message
Transfer Part (MTP) to provide transport of SS7 signalling messages to
and from an SS7 Signalling End Point (SEP) or SS7 Signalling Transfer
Point (STP). In other words, the SG acts as a Signalling Link Terminal
(SLT) [2]. The SG then provides interworking of transport functions
with IP Signalling Transport, in order to transport the MTP3 signalling
messages to the MGC where the peer MTP3 protocol layer exists, as shown
below:
****** SS7 ****** IP *******
*SEP *-----------* SG *-------------* MGC *
****** ****** *******
+----+ +----+
|S7UP| |S7UP|
+----+ +----+
|MTP + |MTP |
| L3 | (NIF) |L3 |
+----+ +----+----+ +----+
|MTP | |MTP |M2UA| |M2UA|
| | | +----+ +----+
|L2 | |L2 |SCTP| |SCTP|
|L1 | |L1 +----+ +----+
| | | |IP | |IP |
+----+ +---------+ +----+
NIF - Nodal Interworking Function
SEP - SS7 Signalling Endpoint
IP - Internet Protocol
SCTP - Stream Control Transmission Protocol (Reference [8])
Figure 1 M2UA in the SG to MGC Application
Note: STPs MAY be present in the SS7 path between the SEP and the SG.
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Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
It is recommended that the M2UA use the services of the Stream
Control Transmission Protocol (SCTP) as the underlying reliable
common signalling transport protocol. The use of SCTP provides
the following features:
- explicit packet-oriented delivery (not stream-oriented)
- sequenced delivery of user messages within multiple streams,
with an option for order-of-arrival delivery of individual
user messages,
- optional multiplexing of user messages into SCTP datagrams,
- network-level fault tolerance through support of multi-homing
at either or both ends of an association,
- resistance to flooding and masquerade attacks, and
- data segmentation to conform to discovered path MTU size
There are scenarios without redundancy requirements and
scenarios in which redundancy is supported below the transport
layer. In these cases, the SCTP functions above MAY NOT be a
requirement and TCP can be used as the underlying common
transport protocol.
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Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
1.3.2 ASP Fail-over Model and Terminology
The M2UA layer supports ASP fail-over functions in order to support a
high availability of call and transaction processing capability. All
MTP2-User messages incoming to a SGP from the SS7 network are assigned
to the unique Application Server, based on the Interface Identifier of
the message.
The M2UA layer supports a n+k redundancy model (active-standby,
loadsharing, broadcast) where n 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.
1.3.3 Client/Server Model
It is recommended that the SGP and ASP be able to support both client
and server operation. The peer endpoints using M2UA SHOULD be
configured so that one always takes on the role of client and the
other the role of server for initiating SCTP associations. The
default orientation would be for the SGP to take on the role of server
while the ASP is the client. In this case, ASPs SHOULD initiate the
SCTP association to the SGP.
The SCTP and TCP Registered User Port Number Assignment for M2UA
is 2904.
1.4 Services Provided by the M2UA Adaptation Layer
The SS7 MTP3/MTP2(MTP2-User) interface is retained at the termination
point in the IP network, so that the M2UA protocol layer is required to
provide the equivalent set of services to its users as provided by the
MTP Level 2 to MTP Level 3.
1.4.1 Support for MTP Level 2 / MTP Level 3 interface boundary
M2UA supports a MTP Level 2 / MTP Level 3 interface boundary that enables
a seamless, or as seamless as possible, operation of the MTP2-User peers
in the SS7 and IP domains. An example of the primitives that need to be
supported can be found in [10].
1.4.2 Support for communication between Layer Management modules
on SG and MGC
The M2UA layer needs to provide some messages that will facilitate
communication between Layer Management modules on the SG and MGC.
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Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
To facilitate reporting of errors that arise because of backhauling MTP
Level 3 scenario, the following primitive is defined:
M-ERROR
The M-ERROR message is used to indicate an error with a received
M2UA message (e.g., an interface identifier value is not known to the
SG).
1.4.3 Support for management of active associations between SG and MGC
The M2UA layer on the SG keeps the state of the configured ASPs. A set
of primitives between M2UA layer and the Layer Management are defined
below to help the Layer Management manage the association(s) between
the SG and the MGC. The M2UA layer can be instructed by the Layer
Management to establish a SCTP association to a peer M2UA node. This
procedure can be achieved using the M-SCTP ESTABLISH primitive.
M-SCTP_ESTABLISH
The M-SCTP_ESTABLISH primitive is used to request, indicate and confirm
the establishment of a SCTP association to a peer M2UA node.
M-SCTP_RELEASE
The M-SCTP_RELEASE primitives are used to request, indicate, and
confirm the release of a SCTP association to a peer M2UA node.
The M2UA layer MAY also need to inform the status of the SCTP
association(s) to the Layer Management. This can be achieved using
the following primitive.
M-SCTP_STATUS
The M-SCTP_STATUS primitive is used to request and indicate the status
of underlying SCTP association(s).
The Layer Management MAY need to inform the M2UA layer of an AS/ASP
status (i.e., failure, active, etc.), so that messages can be exchanged
between M2UA layer peers to stop traffic to the local M2UA user. This
can be achieved using the following primitive.
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Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
M-ASP_STATUS
The ASP status is stored inside M2UA layer on both the SG and MGC
sides. The M-ASP_STATUS primitive can be used by Layer Management to
request the status of the Application Server Process from the M2UA
layer. This primitive can also be used to indicate the status of the
Application Server Process.
M-ASP_MODIFY
The M-ASP_MODIFY primitive can be used by Layer Management to modify
the status of the Application Server Process. In other words, the
Layer Management on the ASP side uses this primitive to initiate
the ASPM procedures.
M-AS_STATUS
The M-AS_STATUS primitive can be used by Layer Management to request
the status of the Application Server. This primitive can also be
used to indicate the status of the Application Server.
1.5 Functions Provided by the M2UA Layer
1.5.1 Mapping
The M2UA layer MUST maintain a map of a Interface ID to a physical
interface on the Signalling Gateway. A physical interface would be a
V.35 line, T1 line/timeslot, E1 line/timeslot, etc. The M2UA layer
MUST also maintain a map of Interface Identifier to SCTP association
and to the related stream within the association.
The SGP maps an Interface Identifier to an SCTP association/stream
only when an ASP sends an ASP Active message for a particular Interface
Identifier. It must be noted, however, that this mapping is dynamic
and could change at any time due to a change of ASP state. This mapping
could even temporarily be invalid, for example during failover of one
ASP to another. Therefore, the SGP MUST maintain the states of AS/ASP
and reference them during the routing of an messages to an AS/ASP.
Note that only one SGP SHOULD provide Signalling Link Terminal
services to an SS7 link. Therefore, within an SG, an Application
Server SHOULD be active for only one SGP at any given point in time.
An example of the logical view of relationship between SS7 link,
Interface Identifier, AS and ASP in an SGP is shown below:
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Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
/-------------------------------------------------+
/ /----------------------------------------------|--+
/ / v |
/ / +----+ act+-----+ +-------+ -+--+|-+-
SS7 link1-------->|IID |-+ +-->| ASP |-->| Assoc | v
/ +----+ | +----+ | +-----+ +-------+ -+--+--+-
/ +->| AS |--+ Streams
/ +----+ | +----+ stb+-----+
SS7 link2-------->|IID |-+ | ASP |
+----+ +-----+
where IID = Interface Identifier
A SGP MAY support more than one AS. An AS MAY support more than
one Interface Identifier.
1.5.2 Support for the management of SCTP associations between the
SGPs and ASPs
The M2UA layer at the SG maintains the availability state of all
configured ASPs, in order to manage the SCTP associations and the
traffic between the SG and ASPs. As well, the active/inactive state
of remote ASP(s) are also maintained. The Active ASP(s) are the
one(s) currently receiving traffic from the SG.
The M2UA layer MAY be instructed by local management to establish an
SCTP association to a peer M2UA node. This can be achieved using the
M-SCTP_ESTABLISH primitive to request, indicate and confirm the
establishment of an SCTP association with a peer M2UA node.
The M2UA layer MAY also need to inform local management of the status of
the underlying SCTP associations using the M-SCTP_STATUS request and
indication primitive. For example, the M2UA MAY inform local management
of the reason for the release of an SCTP association, determined either
locally within the M2UA layer or by a primitive from the SCTP.
Also the M2UA layer may need to inform the local management of the
change in status of an ASP or AS. This may be achieved using the M-ASP
STATUS request or M-AS_STATUS request primitives.
1.5.3 Status of ASPs
The M2UA layer on the SG MUST maintain the state of the ASPs it is
supporting. The state of an ASP changes because of reception of
peer-to-peer messages (ASPM messages as described in Section 3.3.2)
or reception of indications from the local SCTP association. ASP
state transition procedures are described in Section 4.3.1.
At a SGP, an Application Server list MAY contain active and inactive
ASPs to support ASP fail-over procedures. When, for example, both
a primary and a backup ASP are available, M2UA peer protocol is
required to control which ASP is currently active. The ordered
list of ASPs within a logical Application Server is kept updated in
the SGP to reflect the active Application Server Process.
Also the M2UA layer MAY need to inform the local management of the
change in status of an ASP or AS. This can be achieved using the M-ASP
STATUS or M-AS_STATUS primitives.
1.5.4 SCTP Specifics
1.5.4.1 SCTP Stream Management
SCTP allows a user specified number of streams to be opened during
initialization of the association. It is the responsibility of the
M2UA layer to ensure proper management of these streams. Because of
the unidirectional nature of streams, a M2UA layer is not aware of the
stream information from its peer M2UA layer. Instead, the Interface
Identifier is in the M2UA message header.
The use of SCTP streams within M2UA is recommended in order to minimize
transmission and buffering delay, therefore improving the overall
performance and reliability of the signalling elements. A separate
SCTP stream can be used for each SS7 link. Or, an implementation may
choose to split the SS7 link across several streams based on SLS.
This method may be of particular interest for high speed SS7 links
(MTP3b) since high speed links have a 24-bit sequence number and the
stream sequence number is 16-bits.
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Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
SCTP Stream '0' SHOULD NOT be used for MTP2 User Adaptation (MAUP)
messages (see Section 3) since stream '0' SHOULD only be used for ASP
Management (ASPM) messages (see Section 4.3.3).
1.5.5 Seamless SS7 Network Management Interworking
The M2UA layer on the SGP SHOULD pass an indication of unavailability
of the M2UA-User (MTP3) to the local Layer Management, if the
currently active ASP moves from the ACTIVE state. The actions taken by
M2UAon the SGP with regards to MTP Level 2 should be in accordance
with the appropriate MTP specifications.
1.5.6 Flow Control / Congestion
It is possible for the M2UA layer to be informed of IP network
congestion onset and abatement by means of an implementation dependent
function (i.e. an indication from the SCTP). The handling of
this congestion indication by M2UA is implementation dependent.
However, the actions taken by the SG should be accordance with the
appropriate MTP specification and should enable SS7 functionality
(e.g. flow control) to be correctly maintained.
1.5.7 Audit of SS7 Link State
After a failover of one ASP to another ASP, it may be necessary for the
M2UA on the ASP to audit the current SS7 link state to ensure consistency.
The M2UA on the SGP would respond to the audit request with information
regarding the current state of the SS7 link (i.e. in-service,
out-of-service, congestion state, LPO/RPO state).
1.6 Definition of the M2UA Boundaries
1.6.1 Definition of the M2UA / MTP Level 3 boundary
DATA
ESTABLISH
RELEASE
STATE
DATA RETRIEVAL
DATA RETRIEVAL COMPLETE
1.6.2 Definition of the M2UA / MTP Level 2 boundary
DATA
ESTABLISH
RELEASE
STATE
DATA RETRIEVAL
DATA RETRIEVAL COMPLETE
1.6.3 Definition of the Lower Layer Boundary between M2UA and SCTP
The upper layer and layer management primitives provided by SCTP are
provided in Reference [8] Section 9.
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1.6.4 Definition of Layer Management / M2UA Boundary
M-SCTP_ESTABLISH request
Direction: LM -> M2UA
Purpose: LM requests ASP to establish an SCTP association with an
SGP.
M-SCTP_ESTABLISH confirm
Direction: M2UA -> LM
Purpose: ASP confirms to LM that it has established an SCTP
association with an SGP.
M-SCTP_ESTABLISH indication
Direction: M2UA -> LM
Purpose: SGP informs LM that an ASP has established an SCTP
association.
M-SCTP_RELEASE request
Direction: LM -> M2UA
Purpose: LM requests ASP to release an SCTP association with SGP.
M-SCTP_RELEASE confirm
Direction: M2UA -> LM
Purpose: ASP confirms to LM that it has released SCTP association
with SGP.
M-SCTP_RELEASE indication
Direction: M2UA -> LM
Purpose: SGP informs LM that ASP has released an SCTP association.
M-SCTP_RESTART indication
Direction: M2UA -> LM
Purpose: M2UA informs LM that a SCTP Restart indication has
been received.
M-SCTP_STATUS request
Direction: LM -> M2UA
Purpose: LM requests M2UA to report status of SCTP association.
M-SCTP_STATUS indication
Direction: M2UA -> LM
Purpose: M2UA reports status of SCTP association.
M-ASP_STATUS request
Direction: LM -> M2UA
Purpose: LM requests SGP to report status of remote ASP.
M-ASP_STATUS indication
Direction: M2UA -> LM
Purpose: SGP reports status of remote ASP.
M-AS_STATUS request
Direction: LM -> M2UA
Purpose: LM requests SG to report status of AS.
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Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
M-AS_STATUS indication
Direction: M2UA -> LM
Purpose: SG reports status of AS.
M-NOTIFY indication
Direction: M2UA -> LM
Purpose: ASP reports that it has received a NOTIFY message
from its peer.
M-ERROR indication
Direction: M2UA -> LM
Purpose: ASP or SGP reports that it has received an ERROR
message from its peer.
M-ASP_UP request
Direction: LM -> M2UA
Purpose: LM requests ASP to start its operation and send an ASP UP
message to the SGP.
M-ASP_UP confirm
Direction: M2UA -> LM
Purpose: ASP reports that it has received an ASP UP Acknowledgement
message from the SGP.
M-ASP_DOWN request
Direction: LM -> M2UA
Purpose: LM requests ASP to stop its operation and send an ASP DOWN
message to the SGP.
M-ASP_DOWN confirm
Direction: M2UA -> LM
Purpose: ASP reports that is has received an ASP DOWN Acknowledgement
message from the SGP.
M-ASP_ACTIVE request
Direction: LM -> M2UA
Purpose: LM requests ASP to send an ASP ACTIVE message to the SGP.
M-ASP_ACTIVE confirm
Direction: M2UA -> LM
Purpose: ASP reports that is has received an ASP ACTIVE Acknowledgement
message from the SGP.
M-ASP_INACTIVE request
Direction: LM -> M2UA
Purpose: LM requests ASP to send an ASP INACTIVE message to the SGP.
M-ASP_INACTIVE confirm
Direction: M2UA -> LM
Purpose: ASP reports that is has received an ASP INACTIVE
Acknowledgement message from the SGP.
M-LINK_KEY_REG Request
Direction: LM -> M2UA
Purpose: LM requests ASP to register Link Key with SG by sending REG
REQ message.
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Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
M-LINK_KEY_REG Confirm
Direction: M2UA -> LM
Purpose: ASP reports to LM that it has successfully received a REG
RSP message from SG.
M-LINK_KEY_REG Indication
Direction: M2UA -> LM
Purpose: SG reports to LM that it has successfully processed an
incoming REG REQ message from ASP.
M-LINK_KEY_DEREG Request
Direction: LM -> M2UA
Purpose: LM requests ASP to de-register Link Key with SG by sending
DEREG REQ message.
M-LINK_KEY_DEREG Confirm
Direction: M2UA -> LM
Purpose: ASP reports to LM that it has successfully received a
DEREG RSP message from SG.
M-LINK_KEY_DEREG Indication
Direction: M2UA -> LM
Purpose: SG reports to LM that it has successfully processed an
incoming DEREG REQ message from ASP.
2.0 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].
3.0 Protocol Elements
This section describes the format of various messages used in this
protocol.
3.1 Common Message Header
The protocol messages for MTP2-User Adaptation require a message
structure which contains a version, message class, message type, message
length, and message contents. This message header is common among all
signalling 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 | Spare | Message Class | Message Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2 Common Message Header
All fields in an M2UA message MUST be transmitted in the network byte
order, unless otherwise stated.
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3.1.1 Version
The version field (vers) contains the version of the M2UA adaptation
layer. The supported versions are:
Value Version
----- -------
1 Release 1.0
3.1.2 Spare
The Spare field is 8-bits. It SHOULD be set to all '0's by the sender
and ignored by the receiver.
3.1.3 Message Class
The following List contains the valid Message Classes:
Message Class: 8 bits (unsigned integer)
0 Management (MGMT) Message [IUA/M2UA/M3UA/SUA]
1 Transfer Messages [M3UA]
2 SS7 Signalling Network Management (SSNM) Messages [M3UA/SUA]
3 ASP State Maintenance (ASPSM) Messages [IUA/M2UA/M3UA/SUA]
4 ASP Traffic Maintenance (ASPTM) Messages [IUA/M2UA/M3UA/SUA]
5 Q.921/Q.931 Boundary Primitives Transport (QPTM)
Messages [IUA]
6 MTP2 User Adaptation (MAUP) Messages [M2UA]
7 Connectionless Messages [SUA]
8 Connection-Oriented Messages [SUA]
9 Routing Key Management (RKM) Messages (M3UA)
10 Interface Identifier Management (IIM) Messages (M2UA)
11 to 127 Reserved by the IETF
128 to 255 Reserved for IETF-Defined Message Class extensions
3.1.4 Message Type
The following List contains the Message Types for the valid Message
Classes:
MTP2 User Adaptatation (MAUP) Messages
0 Reserved
1 Data
2 Establish Request
3 Establish Confirm
4 Release Request
5 Release Confirm
6 Release Indication
7 State Request
8 State Confirm
9 State Indication
10 Data Retrieval Request
11 Data Retrieval Confirm
12 Data Retrieval Indication
13 Data Retrieval Complete Indication
14 Congestion Indication
15 Data Acknowledge
16 to 127 Reserved by the IETF
128 to 255 Reserved for IETF-Defined MAUP extensions
Morneault, et al [Page 14]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
Application Server Process State Maintenance (ASPSM) messages
0 Reserved
1 ASP Up (UP)
2 ASP Down (DOWN)
3 Heartbeat (BEAT)
4 ASP Up Ack (UP ACK)
5 ASP Down Ack (DOWN ACK)
6 Heartbeat Ack (BEAT ACK)
7 to 127 Reserved by the IETF
128 to 255 Reserved for IETF-Defined ASPSM extensions
Application Server Process 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 127 Reserved by the IETF
128 to 255 Reserved for IETF-Defined ASPTM extensions
Management (MGMT) Messages
0 Error (ERR)
1 Notify (NTFY)
2 to 127 Reserved by the IETF
128 to 255 Reserved for IETF-Defined MGMT extensions
Interface Identifier Management (IIM) Messages
0 Reserved
1 Registration Request (REG REQ)
2 Registration Response (REG RSP)
3 Deregistration Request (DEREG REQ)
4 Deregistration Response (DEREG RSP)
5 to 127 Reserved by the IETF
128 to 255 Reserved for IETF-Defined IIM extensions
3.1.5 Message Length
The Message Length defines the length of the message in octets,
including the header. The Message Length MUST include parameter
padding bytes, if any. The Message Length MUST NOT be longer
than a MTP3 message [2] [3] [5] plus the length of the common and
M2UA message headers.
3.1.6 Variable-Length Parameter Format
M2UA messages consist of a Common Header followed by zero or more
variable-length parameters, as defined by the message type. The
variable-length parameters contained in a message are defined in a
Tag-Length-Value format as shown below.
Morneault, et al [Page 15]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Parameter Tag | Parameter Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \
/ Parameter Value /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Mandatory parameters MUST be placed before optional parameters in a
message.
Parameter Tag: 16 bits (unsigned integer)
The Type field is a 16 bit identifier of the type of parameter. It
takes a value of 0 to 65534. The common parameters used by adaptation
layers are in the range of 0x00 to 0xff. The M2UA specific parameters
have Tags in the range 0x300 to 0x3ff.
The common parameter tags (used by all User Adaptation layers) that
M2UA uses are defined below:
Parameter Value Parameter Name
--------------- --------------
0 (0x00) Reserved
1 (0x01) Interface Identifier (Integer)
2 (0x02) Unused
3 (0x03) Interface Identifier (Text)
4 (0x04) Info String
5 (0x05) Unused
6 (0x06) Unused
7 (0x07) Diagnostic Information
8 (0x08) Interface Identifier (Integer Range)
9 (0x09) Heartbeat Data
10 (0x0a) Unused
11 (0x0b) Traffic Mode Type
12 (0x0c) Error Code
13 (0x0d) Status Type/Information
14 (0x0e) Unused
15 (0x0f) Unused
16 (0x10) Unused
17 (0x11) ASP Identifier
18 (0x12) Unused
19 (0x13) Correlation Id
18-255 Reserved
The M2UA specific parameter Tags defined are as follows:
Parameter Value Parameter Name
--------------- --------------
768 (0x0300) Protocol Data 1
769 (0x0301) Protocol Data 2 (TTC)
770 (0x0302) State Request
771 (0x0303) State Event
772 (0x0304) Congestion Status
773 (0x0305) Discard Status
774 (0x0306) Action
775 (0x0307) Sequence Number
776 (0x0308) Retrieval Result
777 (0x0309) Link Key
778 (0x030a) Local-LK-Identifier
779 (0x030b) Signalling Data Terminal (SDT) Identifier
780 (0x030c) Signailng Data Link (SDL) Identifier
781 (0x030d) Registration Result
782 (0x030e) Registration Status
783 (0x030f) De-Registration Result
784 (0x0310) De-Registration Status
Morneault, et al [Page 16]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
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.
Parameter Value: variable-length.
The Parameter Value field contains the actual information to be
transferred in the parameter.
The total length of a parameter (including Tag, Parameter Length and
Value fields) MUST be a multiple of 4 bytes. If the length of the
parameter is not a multiple of 4 bytes, the sender pads the Parameter
at the end (i.e., after the Parameter Value field) with all zero
bytes. The length of the padding is NOT included in the parameter
length field. A sender MUST NOT pad with more than 3 bytes. The
receiver MUST ignore the padding bytes.
3.2 M2UA Message Header
In addition to the common message header, there will be a M2UA
specific message header. The M2UA specific message header will
immediately follow the common message header, but will only be used
with MAUP messages.
This message header will contain the Interface Identifier. The
Interface Identifier identifies the physical interface at the SG for
which the signalling messages are sent/received. The format of the
Interface Identifier parameter can be text or 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.
The integer formatted Interface Identifier MUST be supported. The
text formatted Interface Identifier MAY optionally be supported.
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 (0x1) | Length=8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier (integer) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3 M2UA Message Header (Integer-based Interface Identifier)
The Tag value for Integer-based Interface Identifier is 0x1. The
length is always set to a value of 8.
Morneault, et al [Page 17]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
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 (0x3) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Interface Identifier (text) /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4 M2UA Message Header (Text-based Interface Identifier)
The Tag value for the Text-based Interface Identifier is 0x3. The
encoding of the Identifier is ANSI X3.4-1986 [7]. The maximum
string length of the text-based Interface Identifier is 255 octets.
The tag length is equal to the string length of the Interface
Identifier name plus four bytes for the Tag and Length fields.
3.3 M2UA Messages
The following section defines the messages and parameter contents.
The M2UA messages will use the common message header (Figure 2) and
the M2UA message header (Figure 3).
3.3.1 MTP2 User Adaptation Messages
3.3.1.1 Data
The Data message contains an SS7 MTP2-User Protocol Data Unit (PDU).
The Data message contains the following parameter:
Protocol Data (mandatory)
Correlation Id (optional)
The format for the Data 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 (0x300) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Protocol Data /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x311) | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Correlation Id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Protocol Data field contains the MTP2-User application message in
network byte order starting with the Signalling Information Octet (SIO).
The Correlation Id parameter uniquely identifies the MSU carried in the
Protocol Data within an AS. This Correlation Id parameter is assigned
by the sending M2UA. The purpose of the Correlation Id is to permit
the newly active ASP to synchronize its processing of the traffic in
each ordered stream with other ASPs in the broadcast group.
Morneault, et al [Page 18]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
The format for a Data Message with TTC PDU 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 (0x301) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Protocol Data /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x13) | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Correlation Id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Protocol Data field contains the MTP2-User application message in
network byte order starting with the Length Indicator (LI) octet.
The Japanese TTC variant uses the spare bits of the LI octet for
priority. The length of the Protocol Data MUST NOT exceed the length
of a MTP2-User application message [2] [3].
3.3.1.2 Data Acknowledge Message
The Data Acknowledge message contains the Correlation Id of the Data
message which the sending M2UA is acknowledging as successfully
processed to the peer M2UA.
The Data Acknowledge message contains the following parameter:
Correlation Id Mandatory
The following format MUST be used for the Data Ack 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 (0x13) | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Correlation Id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Correlation Id parameter of the Data message and the Data Ack
message provide a mechanism, for those SG implementations capable for
taking advantage of them, to obtain an acknowledgement that the MSU
has been transferred to the M2UA peer before acknowleding the MSU to
the SS7 peer, removing the risk of losing messages due to association
failure or SCTP congestion.
The Data Ack message MUST be sent if a Correlation Id parameter is
received from the peer. Otherwise, the Data Ack message MUST NOT be
sent.
Morneault, et al [Page 19]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
If the Data Acknowledge is not sent for Correlation Id(s) or is sent
with Invalid Correlation Id(s), the SS7 link will eventually fail
dueto lack of MTP Level 2 acknowledgements of the SS7 peer's MSUs.
3.3.1.3 Establish (Request, Confirmation)
The Establish Request message is used to establish the SS7 link or to
indicate that the channel has been established. The MGC controls the
state of the SS7 link. When the MGC desires the SS7 link to be
in-service, it will send the Establish Request message. Note that
the SGP MAY already have the SS7 link established at its layer.
If so, upon receipt of an Establish Request, the SGP takes no action
except to send an Establish Confirm.
When the MGC sends an M2UA Establish Request message, the MGC MAY
start a timer. This timer would be stopped upon receipt of an M2UA
Establish Confirm. If the timer expires, the MGC would resend the
M2UA Establish Request message and restart the timer. In other words,
the MGC MAY continue to request the establishment of the datalink
on periodic basis until the desired state is achieved or take some
other action (notify the Management Layer).
The mode (Normal or Emergency) for bringing the SS7 link in service is
defaulted to Normal. The State Request (described in Section 3.3.1.5
below) can be used to change the mode to Emergency.
3.3.1.4 Release (Request, Indication, Confirmation)
This Release Request message is used to release the channel. The
Release Confirm and Indication messages are used to indicate that the
channel has been released.
3.3.1.5 State Request
The State Request message can be sent from a MGC to cause an action
on a particular SS7 link supported by the Signalling Gateway Process.
The SGP sends a State Confirm to the MGC if the action has been
successfully completed. The State Confirm reflects that state value
received in the State Request message.
The State Request message contains the following parameter:
State (mandatory)
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 (0x302) | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| State |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Morneault, et al [Page 20]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
The valid values for State are shown in the following table.
Define Value Description
STATUS_LPO_SET 0x0 Request local processor outage
STATUS_LPO_CLEAR 0x1 Request local processor outage
recovered
STATUS_EMER_SET 0x2 Request emergency alignment
STATUS_EMER_CLEAR 0x3 Request normal alignment (cancel
emergency)
STATUS_FLUSH_BUFFERS 0x4 Flush or clear receive, transmit
and retransmit queues
STATUS_CONTINUE 0x5 Continue or Resume
STATUS_CLEAR_RTB 0x6 Clear the retransmit queue
STATUS_AUDIT 0x7 Audit state of link
STATUS_CONG_CLEAR 0x8 Congestion cleared
STATUS_CONG_ACCEPT 0x9 Congestion accept
STATUS_CONG_DISCARD 0xa Congestion discard
3.3.1.6 State Confirm
The State Confirm message will be sent by the SGP in response to a State
Request from the MGC. The State Confirm reflects that state value
received in the State Request message.
The State Confirm message contains the following parameter:
State (mandatory)
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 (0x302) | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| State |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The valid values for State are shown in the following table. The value
of the State field SHOULD reflect the value received in the State
Request message.
Define Value Description
STATUS_LPO_SET 0x0 Request local processor outage
STATUS_LPO_CLEAR 0x1 Request local processor outage
recovered
STATUS_EMER_SET 0x2 Request emergency alignment
STATUS_EMER_CLEAR 0x3 Request normal alignment (cancel
emergency)
STATUS_FLUSH_BUFFERS 0x4 Flush or clear receive, transmit
and retransmit queues
STATUS_CONTINUE 0x5 Continue or Resume
STATUS_CLEAR_RTB 0x6 Clear the retransmit queue
STATUS_AUDIT 0x7 Audit state of link
STATUS_CONG_CLEAR 0x8 Congestion cleared
STATUS_CONG_ACCEPT 0x9 Congestion accept
STATUS_CONG_DISCARD 0xa Congestion discard
Morneault, et al [Page 21]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
3.3.1.7 State Indication
The MTP2 State Indication message can be sent from a SGP to an ASP to
indicate a condition on a SS7 link.
The State Indication message contains the following parameter:
Event (mandatory)
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 (0x303) | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Event |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The valid values for Event are shown in the following table.
Define Value Description
EVENT_RPO_ENTER 0x1 Remote entered processor outage
EVENT_RPO_EXIT 0x2 Remote exited processor outage
EVENT_LPO_ENTER 0x3 Link entered processor outage
EVENT_LPO_EXIT 0x4 Link exited processor outage
3.3.1.8 Congestion Indication
The Congestion Indication message can be sent from a Signalling Gateway
Process to an ASP to indicate the congestion status and discard status
of a SS7 link. When the MSU buffer fill increases above an Onset
threshold or decreases below an Abatement threshold or crosses a Discard
threshold in either direction, the SGP SHALL send a congestion indication
message when it supports SS7 MTP2 variants that support multiple congestion
levels.
The SGP SHALL send the message only when there is actually a change
in either the discard level or the congestion level to report,
meaning it is different from the previously sent message. In addition,
the SGP SHALL use an implementation dependent algorithm to limit the
frequency of congestion indication messages.
An implementation may optionally send Congestion Indication messages on
a "high priority" stream in order to potentially reduce delay.
The Congestion Indication message contains the following parameters:
Congestion Status (mandatory)
Discard Status (optional)
Morneault, et al [Page 22]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
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 (0x304) | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Congestion Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x305) | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Discard Status |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The valid values for Congestion Status and Discard Status are shown in
the following table.
Define Value Description
LEVEL_NONE 0x0 No congestion
LEVEL_1 0x1 Congestion Level 1
LEVEL_2 0x2 Congestion Level 2
LEVEL_3 0x3 Congestion Level 3
For SS7 networks that do not support multiple levels of congestion, only
the LEVEL_NONE and LEVEL_3 values will be used. For SS7 networks that
support multiple levels of congestion, it is possible for all values to
be used. Refer to [2], [3] and [12] for more details on the Congestion
and Discard Status of SS7 signalling links.
3.3.1.9 Retrieval Request
The MTP2 Retrieval Request message is used during the MTP Level 3
changeover procedure to request the BSN, to retrieve PDUs from the
transmit and retransmit queues or to flush PDUs from the retransmit
queue. Examples of the use of Retrieval Request for SS7 Link
Changeover are provided in Section 5.3.6.
The Retrieval Request message contains the following parameters:
Action (mandatory)
Sequence Number (optional)
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 (0x306) | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Action |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x307) | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Morneault, et al [Page 23]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
The valid values for Action are shown in the following table.
Define Value Description
ACTION_RTRV_BSN 0x1 Retrieve the backward sequence number
ACTION_RTRV_MSGS 0x2 Retrieve the PDUs from the transmit
and retransmit queues
In the Retrieval Request message, the Sequence Number field SHOULD NOT
be present if the Action field is ACTION_RTRV_BSN. The Sequence Number
field contains the Forward Sequence Number (FSN) of the far end if the
Action is ACTION_RTRV_MSGS.
3.3.1.10 Retrieval Confirm
The MTP2 Retrieval Confirm message is sent by the Signalling Gateway
in response to a Retrieval Request message. Examples of the use of
Retrieval Confirm for SS7 Link Changeover are provided in Section
5.3.6.
The Retrieval Confirm message contains the following parameters:
Action (mandatory)
Result (mandatory)
Sequence Number (optional)
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 (0x306) | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Action |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x308) | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Result |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x307) | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The valid values for Action are the same as in Retrieval Request.
The values for Result are shown below: in the following table.
Define Value Description
RESULT_SUCCESS 0x0 Action successful
RESULT_FAILURE 0x1 Action failed
When the Signalling Gateway Process sends a Retrieval Confirm to a
Retrieval Request, it echos the Action field. If the Action was
ACTION_RTRV_BSN and the SGP successfully retrieved the BSN, the SGP
will put the Backward Sequence Number (BSN) in the Sequence Number
field and will indicate a success in the Result field. If the BSN
could not be retrieved, the Sequence Number field will not be included
and the Result field will indicate failure.
Morneault, et al [Page 24]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
For a Retrieval Confirm with Action of ACTION_RTRV_MSGS, the value of
the Result field will indicate success or failure. A failure means
that the buffers could not be retrieved. The Sequence Number field is
not used with ACTION_RTRV_MSGS.
3.3.1.11 Retrieval Indication
The Retrieval Indication message is sent by the Signalling Gateway with
a PDU from the transmit or retransmit queue. The Retrieval Indication
message does not contain the Action or seq_num fields, just a MTP3
Protocol Data Unit (PDU) from the transmit or retransmit queue.
Examples of the use of Retrieval Indication for SS7 Link Changeover are
provided in Section 5.3.6.
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 (0x300) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Protocol Data /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
For TTC Data messages, the following parameter will be used to indicate
a TTC PDU which starts at LI.
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 (0x301) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ TTC Protocol Data /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The M2UA implementation MAY consider the use of the bundling feature
of SCTP for Retrieval Indication messages.
3.3.1.12 Retrieval Complete Indication
The MTP2 Retrieval Complete Indication message is exactly the same as
the MTP2 Retrieval Indication message except that it also indicates
that retrieval is complete. In addition, it MAY contain a PDU (which
MUST be the last PDU) from the transmit or retransmit queue.
3.3.2 Application Server Process Maintenance (ASPM) Messages
The ASPM messages will only use the common message header.
3.3.2.1 ASP Up (ASPUP)
The ASP Up (ASPUP) message is used to indicate to a remote M2UA peer
that the Adaptation layer is ready to receive traffic or maintenance
messages.
Morneault, et al [Page 25]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
The ASPUP message contains the following parameters
ASP Identifier (optional)
Info String (optional)
Note: The ASP Identifier MUST be used where the SGP cannot
identify the ASP by pre-configured address/port number
information (e.g., where an ASP is resident on a Host using
dynamic address/port number assignment).
The format for ASPUP 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 (0xe) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASP Identifier* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ INFO String* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The optional ASP Identifier parameter would contain a unique value
that is locally significant among the ASPs that support an AS. The
SGP should save the ASP Identifier to be used, if necessary, with the
Notify message (see Section 3.3.3.2).
The optional INFO String parameter can carry any meaningful UTF-8 [6]
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.
3.3.2.2 ASP Up Ack
The ASP Up Ack message is used to acknowledge an ASP Up message
received from a remote M2UA peer.
The ASPUP Ack message contains the following parameters:
INFO String (optional)
Morneault, et al [Page 26]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
The format for ASPUP 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 (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ INFO String* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format and description of the optional Info String parameter is the
same as for the ASP UP message (See Section 3.3.2.1).
3.3.2.3 ASP Down (ASPDN)
The ASP Down (ASPDN) message is used to indicate to a remote M2UA peer
that the adaptation layer is not ready to receive traffic or
maintenance messages.
The ASPDN message contains the following parameters
INFO String (optional)
The format for the ASPDN 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 (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ INFO String* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format and description of the optional Info String parameter is the
same as for the ASP Up message (See Section 3.3.2.1).
3.3.2.4 ASP Down Ack
The ASP Down Ack message is used to acknowledge an ASP Down message
received from a remote M2UA peer.
The ASP Down Ack message contains the following parameters:
INFO String (optional)
Morneault, et al [Page 27]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
The format for the ASPDN 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 (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ INFO String* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format and description of the optional Info String parameter is the
same as for the ASP UP message (See Section 3.3.2.1).
3.3.2.5 Heartbeat (BEAT)
The Heartbeat message is optionally used to ensure that the M2UA
peers are still available to each other.
The BEAT message contains the following parameter:
Heartbeat Data Optional
The format for the BEAT 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0009 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Heartbeat Data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The sending node defines the Heartbeat Data field contents. It may
include a Heartbeat Sequence Number and/or Timestamp, or other
implementation specific details.
The receiver of a Heartbeat message does not process this field as
it is only of significance to the sender. The receiver echoes the
content of the Heartbeat Data in a BEAT ACK message.
3.3.2.6 Heartbeat Ack (BEAT ACK)
The Heartbeat ACK message is sent in response to a BEAT message. A
peer MUST send a BEAT ACK in response to a BEAT message. It includes
all the parameters of the received Heartbeat message, without any
change.
The BEAT ACK message contains the following parameter:
Heartbeat Data Optional
Morneault, et al [Page 28]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
The format for the BEAT 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0009 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ Heartbeat Data /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The sending node defines the Heartbeat Data field contents. It may
include a Heartbeat Sequence Number and/or Timestamp, or other
implementation specific details.
The receiver of a Heartbeat message does not process this field as
it is only of significance to the sender. The receiver echoes the
content of the Heartbeat Data in a BEAT ACK message.
3.3.2.7 ASP Active (ASPAC)
The ASPAC message is sent by an ASP to indicate to an SGP that it is
Active and ready to be used.
The ASPAC message contains the following parameters:
Traffic Mode Type (optional)
Interface Identifier (optional)
- Combination of integer and integer ranges, OR
- string (text formatted)
INFO String (optional)
The format for the ASPAC message using integer formatted Interface
Identifiers is as follows:
Morneault, et al [Page 29]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
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 (0xb) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic Mode Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x1=integer) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Interface Identifiers* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x8=integer range) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StartN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StopN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Additional Interface Identifiers /
/ of Tag Type 0x1 or 0x8 \
\ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ INFO String* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format for the ASPAC message using text formatted (string)
Interface Identifiers is as follows:
Morneault, et al [Page 30]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
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 (0xb) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic Mode Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x3=string) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Interface Identifier* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Additional Interface Identifiers /
/ of Tag Type 0x3 \
\ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ INFO String* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Traffic Mode 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 Override
0x2 Load-share
0x3 Broadcast
Within a particular AS, only one Traffic Mode Type can be used.
The Override value indicates that the ASP is operating in Override
mode, where the ASP takes over all traffic in an Application Server
(i.e., primary/backup operation), over-riding any currently active
ASPs in the AS. In Load-share mode, the ASP will share in the traffic
distribution with any other currently active ASPs. In Broadcast mode,
all of the Active ASPs receive all message traffic in the Application
Server.
The optional Interface Identifiers parameter contains a list of
Interface Identifier integers (Type 0x1 or Type 0x8) or text strings
(Type 0x3)indexing the Application Server traffic that the sending
ASP is configured/registered to receive. If integer formatted
Interface Identifiers are being used, the ASP can also send ranges of
Interface Identifiers (Type 0x8). Interface Identifier types Integer
(0x1) and Integer Range (0x8) are allowed in the same message. Text
formatted Interface Identifiers (0x3) cannot be used with either
Integer (0x1) or Integer Range (0x8) types.
Morneault, et al [Page 31]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
If no Interface Identifiers are included, the message is for all
provisioned Interface Identifiers within the AS(s) in which the
ASP is provisioned. If only a subset of Interface Identifiers for an
AS are included, the ASP is noted as Active for all the Interface
Identifiers provisioned for that AS.
Note: If the optional Interface Identifier parameter is present, the
integer formatted Interface Identifier MUST be supported, while the
text formatted Interface Identifier MAY be supported.
An SGP that receives an ASPAC with an incorrect or unsupported Traffic
Mode Type for a particular Interface Identifier will respond with an
Error Message (Cause: Unsupported Traffic Handling Mode).
The format and description of the optional Info String parameter is the
same as for the ASP UP message (See Section 3.3.2.1).
3.3.2.8 ASP Active Ack
The ASP Active (ASPAC) Ack message is used to acknowledge an ASP Active
message received from a remote M2UA peer.
The ASPAC Ack message contains the following parameters:
Traffic Mode Type (optional)
Interface Identifier (optional)
- Combination of integer and integer ranges, OR
- string (text formatted)
INFO String (optional)
The format for the ASPAC Ack message with Integer-formatted Interface
Identifiers is as follows:
Morneault, et al [Page 32]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
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 (0xb) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic Mode Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x1=integer) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Interface Identifiers* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x8=integer range) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StartN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StopN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Additional Interface Identifiers /
/ of Tag Type 0x1 or 0x8 \
\ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ INFO String* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Morneault, et al [Page 33]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
The format for the ASP Active Ack message using text formatted (string)
Interface Identifiers 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 (0xb) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Traffic Mode Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x3=string) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Interface Identifier* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Additional Interface Identifiers /
/ of Tag Type 0x3 \
\ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ INFO String* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format and description of the optional Info String parameter is the
same as for the ASP Up message (See Section 3.3.2.1).
The format of the Traffic Mode Type and Interface Identifier parameters
is the same as for the ASP Active message (See Section 3.3.2.5).
3.3.2.9 ASP Inactive (ASPIA)
The ASP Inactive (ASPIA) message is sent by an ASP to indicate to an
SGP that it is no longer an active ASP to be used from within a list
of ASPs. The SGP will respond with an ASPIA Ack message and either
discard incoming messages or buffer for a timed period and then
discard.
The ASPIA message contains the following parameters:
Interface Identifiers (optional)
- Combination of integer and integer ranges, OR
- string (text formatted)
INFO String (optional)
The format for the ASP Inactive message parameters using Integer
formatted Interface Identifiers is as follows:
Morneault, et al [Page 34]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
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 (0x1=integer) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Interface Identifiers* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x8=integer range) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StartN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StopN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Additional Interface Identifiers /
/ of Tag Type 0x1 or 0x8 \
\ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ INFO String* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format for the ASP Inactive message using text formatted (string)
Interface Identifiers 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 (0x3=string) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Interface Identifier* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Additional Interface Identifiers /
/ of Tag Type 0x3 \
\ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ INFO String* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Morneault, et al [Page 35]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
The format and description of the optional Interface Identifiers and
Info String parameters is the same as for the ASP Active message (See
Section 3.3.2.3).
The optional Interface Identifiers parameter contains a list of
Interface Identifier integers indexing the Application Server traffic
that the sending ASP is configured/registered to receive, but does not
want to receive at this time.
3.3.2.10 ASP Inactive Ack
The ASP Inactive (ASPIA) Ack message is used to acknowledge an ASP
Inactive message received from a remote M2UA peer.
The ASPIA Ack message contains the following parameters:
Interface Identifiers (optional)
- Combination of integer and integer ranges, OR
- string (text formatted)
INFO String (optional)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x1=integer) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Interface Identifiers* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x8=integer range) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StartN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StopN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Additional Interface Identifiers /
/ of Tag Type 0x1 or 0x8 \
\ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ INFO String* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Morneault, et al [Page 36]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
The format for the ASP Inactive Ack message using text formatted
(string) Interface Identifiers 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 (0x3=string) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Interface Identifier* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Additional Interface Identifiers /
/ of Tag Type 0x3 \
\ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ INFO String* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format of the Interface Identifier parameter is the same as for
the ASP Inactive message (See Section 3.3.2.7).
The format and description of the optional Info String parameter is
the same as for the ASP Up message (See Section 3.3.2.1).
3.3.3 Layer Management (MGMT) Messages
3.3.3.1 Error (ERR)
The Error (ERR) message is used to notify a peer of an error event
associated with an incoming message. For example, the message type
might be unexpected given the current state, or a parameter value might
be invalid.
The ERR message contains the following parameters:
Error Code (mandatory)
Interface Identifier (optional)
Diagnostic Information (optional)
The format for the ERR message is as follows:
Morneault, et al [Page 37]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
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 (0xc) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x1, 0x3, or 0x8) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Interface Identifier(s)* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x7) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Diagnostic Information* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Error Code parameter indicates the reason for the Error Message.
The Error parameter value can be one of the following values:
Invalid Version 0x1
Invalid Interface Identifier 0x2
Unsupported Message Class 0x3
Unsupported Message Type 0x4
Unsupported Traffic Handling Mode 0x5
Unexpected Message 0x6
Protocol Error 0x7
Unsupported Interface Identifier Type 0x8
Invalid Stream Identifier 0x9
Not Used in M2UA 0xa
Not Used in M2UA 0xb
Not Used in M2UA 0xc
Refused - Management Blocking 0xd
ASP Identifier Required 0xe
Invalid ASP Identifier 0xf
ASP Active for Interface Identifier(s) 0x10
Invalid Parameter Value 0x11
Parameter Field Error 0x12
Unexpected Parameter 0x13
Not Used in M2UA 0x14
Not Used in M2UA 0x15
Missing Parameter 0x16
The "Invalid Version" error would be sent if a message was
received with an invalid or unsupported version. The Error message
would contain the supported version in the Common header. The
Error message could optionally provide the supported version in
the Diagnostic Information area.
The "Invalid Interface Identifier" error would be sent by a SGP if
an ASP sends a message (i.e. an ASP Active message) with an invalid
(unconfigured) Interface Identifier value. One of the optional
Interface Identifier parameters (Integer-based, text-based or integer
range) MUST be used with this error code to identify the invalid
Interface Identifier(s) received.
Morneault, et al [Page 38]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
The "Unsupported Traffic Handling Mode" error would be sent by a SGP
if an ASP sends an ASP Active with an unsupported Traffic Handling
Mode. An example would be a case in which the SGP did not support
load-sharing. One of the optional Interface Identifier parameters
(Integer-based, text-based or integer range) MAY be used with this
error code to identify the Interface Identifier(s).
The "Unexpected Message" error would be sent by an ASP if it received
a MAUP message from an SGP while it was in the Inactive state.
The "Protocol Error" error would be sent for any protocol anomaly
(i.e. a bogus message).
The "Invalid Stream Identifier" error would be sent if a message
was received on an unexpected SCTP stream (i.e. a MGMT message
was received on a stream other than "0").
The "Unsupported Interface Identifier Type" error would be sent by
a SGP if an ASP sends a Text formatted Interface Identifier and the
SGP only supports Integer formatted Interface Identifiers. When
the ASP receives this error, it will need to resend its message with
an Integer formatted Interface Identifier.
The "Unsupported Message Class" error would be sent if a message with
an unexpected or unsupported Message Class is received.
The "Refused - Management Blocking" error is sent when an ASP Up or
ASP Active message is received and the request is refused for
management reasons (e.g., management lock-out").
The "ASP Identifier Required" is sent by a SGP in response
to an ASPUP message which does not contain an ASP Identifier
parameter when the SGP requires one. The ASP SHOULD resend the
ASPUP message with an ASP Identifier.
The "Invalid ASP Identifier" is send by a SGP in response to an
ASPUP message with an invalid (i.e. non-unique) ASP Identifier.
The "ASP Currently Active for Interface Identifier(s)" error is
sent by a SGP when a Deregistration request is received from an ASP
that is active for Interface Identifier(s) specified in the
Deregistration request. One of the optional Interface Identifier
parameters (Integer-based, text-based or integer range) MAY be used
with this error code to identify the Interface Identifier(s).
The "Invalid Parameter Value " error is sent if a message is received
with an invalid parameter value (e.g., a State Request with an
an undefined State).
The "Parameter Field Error" would be sent if a message with a
parameter that has a wrong length field.
The "Unexpected Parameter" error would be sent if a message contains
an invalid parameter.
The "Missing Parameter" error would be sent if a mandatory parameter
were not included in a message.
The optional Diagnostic information can be any information germane to
the error condition, to assist in identification of the error condition.
In the case of an Invalid Version Error Code the Diagnostic information
includes the supported Version parameter. In the other cases, the
Diagnostic information SHOULD be the first 40 bytes of the offending
message.
Morneault, et al [Page 39]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
3.3.3.2 Notify (NTFY)
The Notify message is used to provide an autonomous indication of M2UA
events to an M2UA peer.
The NTFY message contains the following parameters:
Status Type (mandatory)
Status Information (mandatory)
ASP Identifier (optional)
Interface Identifiers (optional)
INFO String (optional)
The format for the Notify message with Integer-formatted Interface
Identifiers 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 (0xd) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status Type | Status Information |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0xe) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASP Identifier* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x1=integer) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Interface Identifiers* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x8=integer range) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop1* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Start2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier Stop2* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StartN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface Identifier StopN* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Additional Interface Identifiers /
/ of Tag Type 0x1 or 0x8 \
\ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ INFO String* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Morneault, et al [Page 40]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
The format for the Notify message with Text-formatted Interface
Identifiers 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 (0xd) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status Type | Status Information |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0xe) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ASP Identifier* |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x3=string) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Interface Identifier* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ Additional Interface Identifiers /
/ of Tag Type 0x3 \
\ /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag (0x4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ \
\ INFO String* /
/ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Status Type parameter identifies the type of the Notify message.
The following are the valid Status Type values:
Value Description
0x1 Application Server state change (AS_State_Change)
0x2 Other
The Status Information parameter contains more detailed information
for the notification, based on the value of the Status Type. If the
Status Type is AS_State_Change the following Status Information values
are used:
Value Description
1 reserved
2 Application Server Inactive (AS_Inactive)
3 Application Server Active (AS_Active)
4 Application Server Pending (AS_Pending)
These notifications are sent from an SGP to an ASP upon a change in
status of a particular Application Server. The value reflects the
new state of the Application Server. The Interface Identifiers of
the AS MAY be placed in the message if desired.
Morneault, et al [Page 41]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
If the Status Type is Other, then the following Status Information
values are defined:
Value Description
1 Insufficient ASP resources active in AS
2 Alternate ASP Active
3 ASP Failure
In the Insufficient ASP Resources case, the SGP is indicating to an
ASP-INACTIVE ASP(s) in the AS that another ASP is required in order to
handle the load of the AS (Load-sharing mode). For the Alternate ASP
Active case, the formerly Active ASP is informed when an alternate
ASP transitions to the ASP Active state in Override mode. The ASP
Identifier (if available) of the Alternate ASP MUST be placed in the
message. For the ASP Failure case, the SGP is indicating to ASP(s)
in the AS that one of the ASPs has transitioned to ASP-DOWN. The ASP
Identifier (if available) of the failed ASP MUST be placed in the
message.
For each of the Status Information values in Status Type Other, the
Interface Identifiers of the affected AS MAY be placed in the message
if desired.
The format and description of the optional Interface Identifiers and
Info String parameters is the same as for the ASP Active message
(See Section 3.3.2.3).
3.3.4 Interface Identifier Management (IIM) Messages
The Interface Identifier Management messages are optional. They are
used to support automatic allocation of Signalling Terminals or
Signalling Data Links [2][3].
3.3.4.1 Registration Request (REG REQ)
The REG REQ message is sent by an ASP to indicate to a remote M2UA
peer that it wishes to register one or more given Link Keys with the
remote peer. Typically, an ASP would send this message to an SGP,
and expect to receive a REG RSP in return with an associated
Interface Identifier value.
The REG REQ message contains the following parameter:
Link Key (mandatory)
The format for the REG REQ message is as follows
Morneault, et al [Page 42]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
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 = 0x0309 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \
/ Link Key 1 /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \
/ ... /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tag = 0x0309 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \
/ Link Key n /
\ \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Link Key: fixed length
The Link Key parameter is mandatory. The sender of this message
expects the receiver of this message will create a Link Key entry
and assign a unique Interface Identifier value to it, if the Link
Key entry does not yet exist.
The Link Key parameter may be present multiple times in the same
message. This is used to allow the registration of multiple Link
Keys in a single message.
The format of the Link 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-LK-Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signalling Data Terminal Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signalling Data Link Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Local-LK-Identifier: 32-bit integer
The mandatory Local-LK-Identifier field is used to uniquely
(between ASP and SGP) identify the registration request. The
Identifier value is assigned by the ASP, and is used to correlate
the response in a REG RSP message with the original registration
request. The Identifier value MUST remain unique until the REG
RSP is received.
The format of the Local-LK-Identifier field is as follows:
Morneault, et al [Page 43]
Internet Draft SS7 MTP2 User Adaptation Layer Feb 2002
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 = 0x030a | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local-LK-Identifier value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Signalling Data Terminal Identifier
The Signalling Data Terminal Identifier parameter is mandatory.
It identifies the Signalling Data Terminal associated with the
SS7 link for which the ASP is registering. The 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 = 0x030b | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | SDT Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The SDT Identifier is a 32-bit unsigned value which may only be
significant to 12 or 14 bits depending on the SS7 variant which
is supported by the MTP Level 3 at the ASP. Insignificant SDTI
bits are coded 0.
Signalling Data Link Identifier
The Signalling Data Link Identifier parameter is mandatory. It
identifies the Signalling Data Link Identifier associated with
the SS7 link for which the ASP is registering. The 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 = 0x030c | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
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