46766459.002 |12:06:50.164 |AppInfo  |SIPTcp - wait_SdlReadRsp: Incoming SIP TCP message from 10.108.122.56 on port 60863 index 3636099 with 793 bytes:
[272163095,NET]
REGISTER sip:172.19.4.201 SIP/2.0
From: sip:3369@172.19.4.201;tag=61068150-1704-4235-80cf-1c8d6741a1e3
To: sip:3369@172.19.4.201
Call-ID: 4ece3f8b-71e5-4ef8-a521-d11963a4d6c3
CSeq: 5 REGISTER
Max-Forwards: 70
Via: SIP/2.0/TCP 10.108.122.56:60863;branch=z9hG4bK30448e15-875f-4ad2-baca-b9982ba8d1c6
Supported: eventlist,outbound,replaces,vnd.avaya.ipo
Allow: INVITE,ACK,OPTIONS,BYE,CANCEL,NOTIFY,MESSAGE,REFER,INFO,PUBLISH,UPDATE
User-Agent: Avaya Vantage Connect/2.2.0.6 (0001; K175D02A; 329.90.62)
Contact: sip:3369@10.108.122.56:60863;transport=tcp;q=1;expires=3600;+sip.instance="<urn:uuid:e25bebaa-94ae-434e-a392-eb4f68222656>";reg-id=1;mobility="fixed";+av.sip.iptolerance;+av.sip.sig=4;avaya-actions="presence.initiate-pubsub, presence.redirect"
Content-Length:     0

Then the phone sent new register message with different source port so the cucm 

46772443.003 |12:07:28.537 |AppInfo  |SIPTcp - wait_SdlReadRsp: Incoming SIP TCP message from 10.108.122.56 on port 48131 index 3636118 with 797 bytes:
[272163755,NET]


REGISTER sip:172.19.4.201 SIP/2.0
From: sip:3369@172.19.4.201;tag=be697a67-cdda-455b-8262-078c78cf79c4
To: sip:3369@172.19.4.201
Call-ID: 63261304-f35e-46dc-bf4b-2c2427b652cb
CSeq: 1 REGISTER
Max-Forwards: 70
Via: SIP/2.0/TCP 10.108.122.56:48131;branch=z9hG4bKcb5f9fda-137b-4570-a9db-c277426d9565
Supported: eventlist,outbound,replaces,vnd.avaya.ipo
Allow: INVITE,ACK,OPTIONS,BYE,CANCEL,NOTIFY,MESSAGE,REFER,INFO,PUBLISH,UPDATE
User-Agent: Avaya Vantage Connect/2.2.0.6 (0001; K175D02A; 329.90.62)
Contact: sip:3369@10.108.122.56:48131;transport=tcp;q=1;expires=3600;+sip.instance="<urn:uuid:e25bebaa-94ae-434e-a392-eb4f68222656>";reg-id=1;mobility="fixed";+av.sip.iptolerance;+av.sip.sig=4;avaya-actions="presence.initiate-pubsub, presence.redirect"
Content-Length:     0