CSCvf07153 is a pretty simple mistake exacerbated by inconsistent implementation from Cisco.

What is it? Cisco CUBE sends the local timezone of the router in SIP headers when the RFC specifies that GMT should always be used. This causes some SBCs to respond with 400 SIP Parser Error : Missing TIME ZONE and causes calls both inbound and outbound to fail.

The bug lists a workaround, yet the workaround is not complete for two reasons.

1. It only lists the Daylight Saving timezone and not the Standard timezone
2. It lists the timezones only in upper-case, but CUBE (3.16.7S) uses upper-case for Standard time and lower-case for Daylight Saving time.

TAC is updating the bug notes with this info, but it may not show up for a few days. Here’s a proper workaround. Replace CST/CDT/cst/cdt with your timezone:

voice class sip-profiles 27
  response ANY sip-header Date modify "CST" "GMT"
  response ANY sip-header Date modify "CDT" "GMT"
  request ANY sip-header Date modify "CST" "GMT"
  request ANY sip-header Date modify "CDT" "GMT"
  response ANY sip-header Date modify "cdt" "GMT"
  request ANY sip-header Date modify "cdt" "GMT"
  response ANY sip-header Date modify "cst" "GMT"
  request ANY sip-header Date modify "cst" "GMT"

Here’s an example of the incorrect SIP timezone formatting sent because of this bug.

Sent: 
INVITE sip:6125551234@10.0.0.1:5060;transport=UDP SIP/2.0
Via: SIP/2.0/UDP 10.0.0.2:5060;branch=z9hG4bK5A363
Remote-Party-ID: <sip:16085552345@10.0.0.2>;party=calling;screen=no;privacy=off
From: <sip:16085553456@10.0.0.2:5060>;tag=1D8B50-E47
To: "MINNEAPOLIS MN" <sip:6125551234@10.0.0.2:5060;transport=UDP>;tag=7361410-7f000001-13c4-20b168-db0af231-20b168
Date: Fri, 16 Feb 2018 21:44:18 CST
Call-ID: 739def8-7f000001-13c4-20b168-cdb25ce6-20b168@10.0.0.2
Supported: 100rel,timer,resource
-priority,replaces,sdp-anat
Min-SE: 1800
Cisco-Guid: 2676538289-0315298280-2158725867-3116844794
User-Agent: Cisco-SIPGateway/IOS-15.5.3.S7
Allow: INVITE, OPTIONS, BYE, CANCEL, ACK, PRACK, UPDATE, REFER, SUBSCRIBE, NOTIFY, INFO, REGISTER
CSeq: 101 INVITE
Max-Forwards: 70
Timestamp: 1518839058
Contact: <sip:16085553456@10.0.0.2:5060>
Expires: 60
Allow-Events: telephone-event
Content-Type: application/sdp
Content-Length: 281
... removed for brevity ...

Received: 
SIP/2.0 400 SIP Parser Error : Missing TIME ZONE, line 6, column 33
From: <sip:16085553456@10.0.0.2:5060>;tag=1D8B50-E47
To: "MINNEAPOLIS MN"<sip:6125551234@10.0.0.2:5060;transport=UDP>;tag=7361410-7f000001-13c4-20b168-db0af231-20b168
Call-ID: 739def8-7f000001-13c4-20b168-cdb25ce6-20b168@10.0.0.2
CSeq: 101 INVITE
... removed for brevity ...

And here’s the inconsistent case, note the previous example used CST, this uses cdt.

fit-cube-charter#
286095: Mar 12 08:13:06.847 cdt: //176035/171A5F000000/SIP/Msg/ccsipDisplayMsg:
Sent:
INVITE sip:16125551234@10.0.0.1 SIP/2.0
Via: SIP/2.0/UDP 10.0.0.2:5060;branch=z9hG4bK2040E1517
Remote-Party-ID: "Widgets Co" <sip:16085554567@10.0.0.2>;party=calling;screen=yes;privacy=off
From: "Widgets Co" <sip:16085554567@10.0.0.2>;tag=7898CDFA-238E
To: <sip:16125551234@10.0.0.1>
Date: Mon, 12 Mar 2018 08:13:06 cdt
Call-ID: EE69AE64-252D11E8-BED98AEB-B9C746FA@10.0.0.2
Supported: 100rel,timer,resource-priority,replaces,sdp-anat
Min-SE: 1800
Cisco-Guid: 0387604224-0000065536-0000003119-0182460076
User-Agent: Cisco-SIPGateway/IOS-15.5.3.S7
Allow: INVITE, OPTIONS, BYE, CANCEL, ACK, PRACK, UPDATE, REFER, SUBSCRIBE, NOTIFY, INFO, REGISTER
CSeq: 101 INVITE
Timestamp: 1520860386
Contact: <sip:16085554567@10.0.0.2:5060>
Expires: 60
Allow-Events: kpml, telephone-event
Max-Forwards: 68
Session-Expires: 1800
Content-Type: application/sdp
Content-Disposition: session;handling=required
Content-Length: 246
... removed for brevity ...


286096: Mar 12 08:13:06.857 cdt: //176035/171A5F000000/SIP/Msg/ccsipDisplayMsg:
Received:
SIP/2.0 400 SIP Parser Error : Missing TIME ZONE, line 6, column 33
From: "Widgets Co"<sip:16085554567@10.0.0.2>;tag=7898CDFA-238E
To: <sip:16125551234@10.0.0.1>
Call-ID: EE69AE64-252D11E8-BED98AEB-B9C746FA@10.0.0.2
CSeq: 101 INVITE
... removed for brevity ...