Each SCP should establish two socket connections to each DCMServer – one for Node messages and one for CMSD messages. Messages should be distributed to both DCM- Servers (and the associated socket connections.) Under normal conditions, NODE mes- sages should be distributed on the two Node socket connections and CMSD messages should be distributed on the two CMSD connections. If one DCMServer fails, all node messages shall be routed to the remaining node socket connection and all CMSD mes- sages shall be routed to the remaining CMSD socket connection on the remaining DCMServer.
Note that messages sent on one connection may receive the response on the same or the other connection. In other words, there is no guarantee that the response will be sent on the same connection of the request message.
The SMS/800 will listen for TCP connection requests from the SCPs (IP addresses of the DCMServers and port number for each socket connections will be provided to each SCP). The SMS/800 will not initiate connection requests to the SCPs (i.e SCPs do not need to listen for connection request.)
The TCP socket connection shall not be closed when there is no message traffic. If the TCP socket connection is lost for any reason, the SCP shall try to re-establish the socket connection at regular intervals until the connection is established successfully.Each SCP shall provide two or more Wide Ara Network (WAN) links to the SMS/800. Appropriate routing protocol shall be used to distribute data traffic on the available WAN links. Each SCP shall also provide WAN links to the Disaster Recovery SMS/800 system.