R2511-HP MSR Router Series Voice Configuration Guide(V5)

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Configuring call release cause code mapping
Configuration prerequisites
If a SIP server is used to forward calls, complete the configurations on the SIP server.
Configuration procedure
No matter whether a voice call is cleared normally or abnormally, a message with the call release cause
code will be sent. The default SIP status code to PSTN release cause code mappings and PSTN release
cause code to SIP status mappings are used for communication between a SIP network and a PSTN. For
more information about these default mappings, see Voice Command Reference. To adapt to more
complex network applications, you can change the default mappings through command lines.
To configure PSTN release cause code to SIP status code mappings and SIP status code to PSTN release
cause code mappings:
Ste
p
Command Remarks
1. Enter system view.
system-view N/A
2. Enter voice view.
voice-setup N/A
3. Enter SIP client view.
sip N/A
4. Configure a PSTN release
cause code to SIP status
code mapping.
reason-mapping pstn pstn-code
sip sip-code
Optional.
For the default PSTN release cause code
to SIP status code mappings, see Voice
Command Reference. Because the PSTN
release cause code 16 corresponds to a
SIP request message, instead of a SIP
status code, you can configure no SIP
status code for 16.
5. Configure a SIP status
code to PSTN release
cause code mapping.
reason-mapping sip sip-code
pstn pstn-code
Optional.
For the default SIP status code to PSTN
release cause code mappings, see Voice
Command Reference.
Configuring periodic refresh of SIP sessions
In a high-volume traffic environment, if a BYE message gets lost for a session, the call proxy server will not
know that the session has ended, and thus still maintains the state information for the call, which wastes
resources of the server. To solve this problem, the RFC 4082 defines a session timer mechanism for SIP
sessions: the UA sends periodic re-INVITE or UPDATE requests (referred to as session refresh requests) to
notify the proxy server about the current state of the session. The interval for sending session refresh
requests is determined through the negotiation of both sides.
Two new header fields are added to the session refresh requests:
• Session-Expires—Conveys the maximum session expiration time, that is, if no refresh request is
received during this time, the session is considered ended.
• Min-SE—Conveys the minimum session expiration time, which is used to avoid frequent refresh
requests from occupying network bandwidth.
Configuration prerequisites
If calls need to be routed to a SIP server, complete the configuration on the SIP server first.