1、ASP-DOWN: The remote M3UA peer at the ASP is unavailable and/or therelated SCTP association is down. Initially all ASPs will be in thisstate. An ASP in this state SHOULD NOT be sent any M3UA messages,with the exception of Heartbeat, ASP Down Ack and Error messages.ASP远端 M3UA对等体不可用或者相关的 SCTP偶联没有建立。初始
2、时所有的ASP都处于此状态。一个 ASP在这个状态不能发送任何 M3UA消息，除了心跳、ASP DOEN ACK 和 ERROR消息。ASP-INACTIVE: The remote M3UA peer at the ASP is available (and therelated SCTP association is up) but application traffic is stopped.In this state the ASP SHOULD NOT be sent any DATA or SSNM messagesfor the AS for which the ASP is i
3、nactive.ASP-ACTIVE: The remote M3UA peer at the ASP is available andapplication traffic is active (for a particular Routing Context orset of Routing Contexts).SCTP CDI: The SCTP CDI denotes the local SCTP layers CommunicationDown Indication to the Upper Layer Protocol (M3UA) on an SGP. Thelocal SCTP
4、 layer will send this indication when it detects the lossM3UA_LINKICTVE M3UA_LINKESTBHM3UA_LINKDOWAsp Inactive/Asp Inactive Ak/ ltNotify ti/ ti M3UA backout sceful/Sctp-CDIM3UA_LINKCTIVESCTP-RI Asp Down rAckr SCTP-RI TP-ISCTPDIestblih scflAsp Uorckof connectivity to the ASPs peer SCTP layer. SCTP CD
5、I is understoodas either a SHUTDOWN_COMPLETE notification or COMMUNICATION_LOSTnotification from the SCTP layer.SCTP RI: The local SCTP layers Restart indication to the upper layerprotocol (M3UA) on an SG. The local SCTP will send this indicationwhen it detects a restart from the ASPs peer SCTP laye
6、r.AS-DOWN: The Application Server is unavailable. This state impliesthat all related ASPs are in the ASP-DOWN state for this AS.Initially the AS will be in this state. An Application Server is inthe AS-DOWN state when it is removed from a configuration.AS-INACTIVE: The Application Server is availabl
7、e but no applicationtraffic is active (i.e., one or more related ASPs are in the ASP-INACTIVE state, but none in the ASP-ACTIVE state). The recoverytimer T(r) is not running or has expired.ASP UpThe ASP Up message is used to indicate to a remote M3UA peer that theadaptation layer is ready to receive
8、 any ASPSM/ASPTM messages for allRouting Keys that the ASP is configured to serve.ASP Up Acknowledgement (ASP Up Ack)The ASP UP Ack message is used to acknowledge an ASP Up messagereceived from a remote M3UA peer.SCCP Transport between IPSPs* IP * IPSP * * IPSP * *+-+ +-+|SCCP- | |SCCP- | User | | U
9、ser |+-+ +-+| SCCP | | SCCP |+-+ +-+| M3UA | | M3UA |+-+ +-+| SCTP | | SCTP |+-+ +-+| IP | | IP |+-+ +-+|_|M3UA 链路集：SGP 和 ASP 之间的多条链路组成一个链路集。一个链路集的所有链路为同一个 AS 服务。链路集当中链路的状态决定链路集的状态。ASP 的链路集有三种状态：DOWN、INACTIVE、ACTIVE。SGP 的链路有四种状态：DOWN、INACTIVE、PENDING、ACTIVE。MGW 中的 M3UA 工作为 SGP。链路集处于DOWN 状态表示链路集中的所有链
10、路处于 DOWN 或 UNESTABLISH 状态。链路集处于INACTIVE 状态表示链路集中没有一条链路处于 ACTIVE 状态，但至少有一条链路处于INACTIVE 状态。链路集处于 ACTIVE 状态表示链路集中的链路至少有一条处于 ACTIVE状态。链路集处于 PENDING 状态表示链路中的最后一条处于 ACTIVE 状态的链路变为非ACTIVE 状态，此时 SGP 的 M3UA 实体启动一个 PENDING 定时器，同时缓存收到报文。如果在定时器超时前，链路集中有链路恢复为 ACTIVE 状态，则链路集恢复为 ACTIVE 状态，同时将缓存的报文发送出去。如果定时器超时，链路集状
11、态迁移至DOWN、INACTIVE 状态（根据链路集中链路的状态） 。M3UA 路由：从源实体到目的实体的路径称之为路由。一条路由对应一个链路集，多条路由可以对应到同一个链路集上。源实体和目的实体间可以存在多条路由。路由有两种状态：可达、不可达。在 SGP 中，路由状态完全依赖于链路集的状态，链路集处于 ACTIVE 或PENDING 状态，路由可达，否则，路由不可达。在 ASP 中，路由状态依赖于链路集状态和 SG 到 SS7 网络的状态。M3UA 链路有四种状态：UNESTABLISH、DOWN、INACTIVE、ACTIVE。链路处于UNESTABLISH 状态表示 SGP 和 ASP 间尚未建立起 SCTP 连接。链路处于 DOWN 状态表示 SCTP 连接已经建立好，但是还没有完成 M3UA draft 07 中的 ASP UP 过程。链路处于INACTIVE 状态表示已经完成了 ASP UP 的过程，但是还没有完成 ASP ACTIVE 的过程。链路处于 ACTIVE 状态表示已经完成了 ASP ACTIVE 的过程，具体的状态迁移过程参照协议 M3UA draft 07。
