SIP SRST Registration Issue

[msloan]

Hello,

I'm trying to register a 7945 SIP phone in SRST to a 2921 gateway but can't get it to work.  I have the SRST reference assigned in CUCM and when I span the switchport that my voice gateway is connected to I can see the 7945 sending register messaages to the sip source address on the vgwbut when I debug ccsip on the gateway I don't see any activity at all.  Here's my the sip config on the gateway:

voice service voip

allow-connections sip to sip

sip

  bind control source-interface GigabitEthernet0/0

  bind media source-interface GigabitEthernet0/0

  registrar server

!

!

voice register global

max-dn 30

max-pool 2

!

voice register pool  1

id network 172.18.20.0 mask 255.255.255.0

proxy 172.16.220.254

dtmf-relay rtp-nte

codec g711ulaw

!

voice register pool  2

id network 172.17.120.0 mask 255.255.255.0

proxy 172.16.220.254

dtmf-relay rtp-nte

codec g711ulaw

sip-ua

registrar ipv4:172.16.220.254 expires 600

Please let me know if you see an error in the config or have a suggestion to resolve this.

Thank you

[msloan]

So I worked with TAC on this and we exported the traffic directly from the vgw interface to confirm the same from above.  The phone SIP register messages arrive at the gateway and after a reboot of the vgw they were even accepted and the phone showed as registered on the vgw but the gateway itself never replies to the phone so it just sits there in 'registering' mode.  I'll update here when we conclude what the issue is.

[msloan]

The issue ending up being a misconfiguration under  call-manager-fallback.  I mistakenly put in 'ip source-address x.x.x.x  port 5060' which was conflicting with voice register global.  I'm still  not sure why the sniffer didn't show the actual SIP IP packets coming in, but the phones are working so I won't push my luck....