SIP/2.0 503 Service Unavailable Observed in Expressway-C trace
SIP/2.0 503
Service Unavailable
Via: SIP/2.0/TCP 1.1.1.241_EXPC:5060;egress-zone=CEtcp192168994;branch=z9hG4bK3eca9d5dc4e26de65b1b83f501cea485458555;proxy-call-id=51ce23fa-d8d1-4c22-9579-ade0f631d257;rport,SIP/2.0/TLS 1.1.1.241_EXPC:5073;branch=z9hG4bK1e991e55187479dada6391ef5adf084024563;x-cisco-local-service=nettle;received=1.1.1.241_EXPC;rport=30979;ingress-zone=DefaultZone,SIP/2.0/TLS 1.1.1.241_EXPC:5061;egress-zone=DefaultZone;branch=z9hG4bKb340db4a70e04cc037ea7de16e55df58458554.3d8de2b0006ebe59e4c4ae2fde61ae57;proxy-call-id=1ceee43f-3413-4f0f-bfcb-aed8a3b2ad03;received=1.1.1.241_EXPC;rport=29605,SIP/2.0/TLS 1.1.1.246_EXPE:7001;egress-zone=UCtoEXPC2;branch=z9hG4bKf0e07263c19c7bfd6133775994af916998831.7b4bb0bfbe6838be4f4507d0ce70df61;proxy-call-id=bc3fdcb9-f10b-4f23-a0d1-1e59e49de578;received=1.1.1.246_EXPE;rport=7001;ingress-zone=UCtoEXPE2,SIP/2.0/TLS 0.0.0.0_USER:43932;branch=z9hG4bK00004aa4;received=2.2.2.2_EXPEPUB;rport=43932;ingress-zone=CollaborationEdgeZone
Call-ID: aefdce71-0af2001c-00004664-00007833@0.0.0.0_USER
CSeq: 101 INVITE
From: “Jason Neurohr” <sip:30822@1.1.1.1_CUCM>;tag=aefdce710af2021f0000027c-00000f51
To: <sip:12345@domain.com.au>;tag=698699~2004fc79-b651-49b6-be90-35de0e0192d1-48112662
Server: Cisco-CUCM10.5
Date: Wed, 28 Dec 2016 02:37:57 GMT
Allow-Events: presence
Reason: Q.850 ;cause=41
Observed on CUCM trunk
Status Reason local=2
Discussion This issue occurred on an Expressway pair where both MRA and B2B were configured. The zone towards CUCM was configured to use a non-standard port and this configuration was reciprocated on the CUCM trunk and security profile.