Inbound calls from one gateway going outbound different gateway

[RichardMoore20826]

All,

I have SBCs in multiple locations. Sip signaling is being established on one SBC in one location; RTP is being established to another SCB in different locations. These locations are in different cities... and it all works. 

Why is this happening and how can I configure to use the source router for all communications?

Thanks

[Roger Kallberg · Accepted solution]

You need to provide some more details than this for anyone that doesn’t have insight into your setup to be able to give you any advice. Please describe the call flow and provide as much details as you can.

[RichardMoore20826]

Basically, the call comes into the Indy gateway and connects to the call manager. The SDP c= address changes from the Indy SBC to the NYC SBC and the RTP is established via NYC.

SIP Signalling

IP PSTN -> SBC (Indy) --> CUCM

RTP

CUCM --> SBC (NYC)

Below is the initial Invite from the SBC to CUCM SDP

v=0
o=CiscoSystemsSIP-GW-UserAgent 5437 5388 IN IP4 10.x.x.x
s=SIP Call
c=IN IP4 10.80.20.40
t=0 0
m=audio 19280 RTP/AVP 0 101
c=IN IP4 10.80.20.40
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=ptime:20

Below is the CUCM 200 OK w/SDP to a gateway in NYC; the IP is not the gateway of the inbound call.

v=0
o=CiscoSystemsCCM-SIP 8017015 1 IN IP4 10.x.x.x
s=SIP Call
c=IN IP4 10.111.115.72
b=TIAS:64000
b=CT:64
b=AS:64
t=0 0
m=audio 26550 RTP/AVP 0 101
a=ptime:20
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15

[Roger Kallberg]

Suggest that you change that you tagged my response as an answer to you query. Otherwise you're likely not get much help on this.

On your question, sorry but I have no ideas to why this would be.