draft-ietf-sigtran-m2pa-03.txt

No7信令,我需要交换类似的代码, 请店长审核,谢谢了,急着交换,谢谢

                      | MTP3 Stop   |                              |
                      |             V                              |
                      |       +-----------+                        |
                      +<------|  PROVING  |----------------------->+
                      |       +-----------+     SCTP Comm Error    |
                      |             |        OR SCTP Comm Lost     |
                      |             |                              |
                      |             | T2 Expiry                    |
                      | MTP3 Stop   |                              |
                      |             V                              |
                      |       +-----------+                        |
                      +<------|  ALIGNED  |                        |
                              |   READY   |----------------------->+
                              +-----------+                        |
                                    |           SCTP Comm Error    |
                                    |        OR SCTP Comm Lost     |
                                    |        OR T3 Expiry          |
                                    |                              |
                                    | Receive LS Proving Complete  |
                                    | OR Receive User Data         |
                                    |                              |
                                    V                              |
                              +-----------+                        |
                              |    INS    |                        |
                              +-----------+                        |
                                    |                              |
                                    |                              |
                                    |                              |

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                                    |                              |
                                    |                              |
                                    |    MTP3 Stop                 |
                                    | OR SCTP Comm Error           |
                                    | OR SCTP Comm Lost            |
                                    | OR T6 Expiry                 |
                                    |                              |
                                    V                              |
                              +-----------+                        |
                              | RETRIEVAL |----------------------->+
                              +-----------+    Retrieval Complete
                                            OR MTP3 Start

                Figure 6: M2PA Link State Transition Diagram


Figure 7 illustrates state changes in the M2PA management of the SCTP
association together with the causing events.  Note that some of the
error conditions are not shown in the state diagram.

Following is a list of the M2PA Association States and a description
of each.

IDLE - State of the association during power-up initialization.

ASSOCIATE - M2PA is attempting to establish an SCTP association.

ESTABLISHED - SCTP association is established. 


                             +-----------+
        +------------------->|   IDLE    |
        |                    +-----------+
        |                          |
        | (Issue SCTP              | Associate
        |    Abort)                | (Issue SCTP associate)
        |                          |
        |                          |   +----------------------+
        |                          |   |         (Issue SCTP  |
        |                          V   V          associate)  |
        |      Abort         +-----------+                    |
        +<-------------------| ASSOCIATE |------------------->+
        |                    +-----------+    SCTP Comm Error |
        |                          |                          |
        |                          |                          |
        |                          | SCTP Comm Up             |
        |                          |                          |
        |                          V                          |
        |      Abort         +-------------+                  |
        +<-------------------| ESTABLISHED |----------------->+
                             +-------------+   SCTP Comm Error
                                            OR SCTP Comm Lost

                Figure 7: M2PA Association State Transition Diagram

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4.  Procedures

4.1 Procedures to Support MTP2 Features

4.1.1 Signal Unit Format, Delimitation, Acceptance

Messages for transmission across the network must follow the format
described in section 2.

SCTP provides reliable, in-sequence delivery. Therefore the related
functionality of MTP2 is not needed. SCTP does not provide functions
related to Link State Control in MTP2. These functions must be
provided by M2PA.


4.1.2 MTP and SCTP Entities

This section describes how M2PA relates MTP and SCTP entities.

To prevent duplicate associations from being established, it must be
decided in advance which endpoint initiates the establishment of the
association. In a pair of endpoints, the endpoint that initiates the
establishment of the association is called the client. The other
endpoint is the server. An endpoint may be a client in its
relationship with one endpoint, and a server in its relationship with
another endpoint. The designations of client and server are needed
only to decide which endpoint initiates the establishment of the
association. After that, the endpoints function as peers.

The client initiates the association using the server's IP address and
the M2PA well-known port number as the destination endpoint. If only
one association is to be established between these two IP addresses,
then the client should use its own IP address and the M2PA well-known
port number as the source endpoint.

If it is desirable to create multiple associations (for multiple
links) between the two IP addresses, the client uses a different local
port number for each association. 

The client M2PA should establish the association for a link when the
link is configured for operation by MTP signaling management. 

Whenever the association is terminated, the client M2PA should
establish the association as soon as the termination procedure is
complete.

The client M2PA establishes an association by sending the SCTP
ASSOCIATE primitive to SCTP. The client should attempt to establish
the association periodically until it is successful.

Once the association is established and MTP3 has issued its Start
Request, M2PA begins the alignment procedure. The M2PA at either end
may initiate the alignment procedure first. There is no client/server
distinction once the SCTP association is established.

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Each combination of client IP address/port and server IP address/port
(i.e., each association) must be mapped to the same Signaling Link
Code (SLC) in the client and server, so that each endpoint knows which
link is being created at the time the SCTP association is
established. However, M2PA does not do any processing based on the
SLC.

Following are examples of the relationships between associations and
links. Note that a link is an SCTP association identified by two
endpoints, in this case a client and server. Each endpoint is
identified by an IP address and port number. Each association is
mapped to an SLC. 

Figure 8 shows a case with two IPSPs, each with two IP addresses. Two
associations are the links that connect the two IPSPs. Since these
links are in the same link set, they must have different SLCs.

Table 1 shows the relationships in tabular form. Table 1 is only
conceptual. The actual method for mapping the SCTP associations to the
SLCs is implementation dependent.


                IPSP X                        IPSP Y

            +-------------+               +-------------+
            |             |     SCTP      |             |
            |         IPA | association 1 | IPB         |
            |   port = PW +---------------+ port = PW   |
            |     SLC = a |               | SLC = a     |
            |      Client |               | Server      |
            |             |               |             |
            |             |     SCTP      |             |
            |         IPC | association 2 | IPD         |
            |   port = PW +---------------+ port = PW   |
            |     SLC = b |               | SLC = b     |
            |      Client |               | Server      |
            |             |               |             |
            +-------------+               +-------------+

      IPx    = IP address
      PW     = Well-known port number for M2PA


                Figure 8: Associations and Links - 
                 Two IPSPs with Two IP Addresses Each









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     +-------------+---------------------------------------+-----+
     | Association |      Client       |      Server       | SLC |
     |             +------------+------+------------+------+     |
     |             | IP address | Port | IP address | Port |     |
     +=============+============+======+============+======+=====+
     |      1      |    IPA     |  PW  |    IPB     |  PW  |  a  |
     +-------------+------------+------+------------+------+-----+
     |      2      |    IPC     |  PW  |    IPD     |  PW  |  b  |
     +-------------+------------+------+------------+------+-----+

                Table 1: Associations and SLCs - 
                 Two IPSPs with Two IP Addresses Each


Figure 9 and Table 2 show an example with three IPSPs. Note that in
this example, the two links are in different link sets. Therefore, it
is possible that the values a and b may be equal.





































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                IPSP X                        IPSP Y

            +-------------+               +-------------+
            |             |     SCTP      |             |
            |         IPA | association 1 | IPB         |
            |   port = PW +---------------+ port = PW   |
            |     SLC = a |               | SLC = a     |
            |      Client |               | Server      |
            |             |               |             |
            |             |     SCTP      |             |
            |         IPC | association 2 |             |
            |   port = PW +-------+       |             |
            |     SLC = b |       |       |             |
            |      Client |       |       |             |
            |             |       |       |             |
            +-------------+       |       +-------------+
                                  |
                                  |
                                  |           IPSP Z
                                  |
                                  |       +-------------+
                                  |       |             |
                                  |       | IPD         |
                                  +-------+ port = PW   |
                                          | SLC = b     |
                                          | Server      |
                                          |             |
                                          |             |
                                          |             |
                                          |             |
                                          |             |
                                          |             |
                                          |             |
                                          +-------------+

      IPx    = IP address
      PW     = Well-known port number for M2PA

                Figure 9: Associations and Links - 
                 One IPSP Connected to Two IPSPs


     +-------------+---------------------------------------+-----+
     | Association |      Client       |      Server       | SLC |
     |             +------------+------+------------+------+     |
     |             | IP address | Port | IP address | Port |     |
     +=============+============+======+============+======+=====+
     |      1      |    IPA     |  PW  |    IPB     |  PW  |  a  |
     +-------------+------------+------+------------+------+-----+
     |      2      |    IPC     |  PW  |    IPD     |  PW  |  b  |
     +-------------+------------+------+------------+------+-----+

                Table 2: Associations and SLCs - 
                 One IPSP Connected to Two IPSPs

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Figure 10 and Table 3 show two associations between the same
endpoints. This is accomplished by using different port numbers for
each association at the client.


                IPSP X                        IPSP Y

            +-------------+               +-------------+
            |             |     SCTP      |             |
            |         IPA | association 1 | IPB         |
            |   port = P1 +---------------+ port = PW   |
            |     SLC = a |               | SLC = a     |
            |      Client |               | Server      |
            |             |               |             |
            |             |     SCTP      |             |
            |         IPA | association 2 | IPB         |
            |   port = PW +---------------+ port = PW   |
            |     SLC = b |               | SLC = b     |
            |      Client |               | Server      |
            |             |               |             |
            +-------------+               +-------------+

      IPx    = IP address
      P1     = Pre-selected port number for Client
      PW     = Well-known port number for M2PA

                Figure 10: Associations and SLCs -
             Multiple Associations Between Two IP Addresses


     +-------------+---------------------------------------+-----+
     | Association |      Client       |      Server       | SLC |
     |             +------------+------+------------+------+     |
     |             | IP address | Port | IP address | Port |     |
     +=============+============+======+============+======+=====+
     |      1      |    IPA     |  P1  |    IPB     |  PW  |  a  |
     +-------------+------------+------+------------+------+-----+
     |      2      |    IPA     |  PW  |    IPB     |  PW  |  b  |
     +-------------+------------+------+------------+------+-----+

                Table 3: Associations and SLCs -
             Multiple Associations Between Two IP Addresses


The association shall contain two streams in each direction. Stream 0
is designated for Link Status messages. Stream 1 is designated for
User Data and Proving Data messages.