Migration 3CX from CVS to VVP
Posted by Jay Wattage on 30 October 2020 01:59 PM


There are some changes to the number format for SIP Trunks when moving from Voyager CVS to Voyager VVP.  This technical note provides some details on the formats used and a simplified path to migrations.


This testing was performed on the latest 3CX server (local install) version 16.0.641


VVP SIP Trunk uses the international standard E.164 format. This means that a leading “+” is inserted as a prefix.  Whilst this avoids any ambiguity in number format, it does mean that the DID/DDI Numbers have to modified on 3CX.

INVITE Format on CVS

Request-Line: INVITE sip:6436660022@;transport=udp SIP/2.0
Message Header
   Record-Route: <sip:;lr=on;ftag=jjry1XU34Ng6a>
   Via: SIP/2.0/UDP;branch=z9hG4bK7733.e0f6be51f2c433ed35bcdb1d656fc4a5.0
   Via: SIP/2.0/UDP;received=;rport=11000;branch=z9hG4bK1Um….
   Max-Forwards: 48
   From: "21995498" <sip:6421995498@>;tag=jjry1XU34Ng6a
   To: <sip:6436660022@;transport=udp>

INVITE Format on VVP

Request-Line: INVITE SIP/2.0
Message Header
   Record-Route: <sip:;lr=on;ftag=N56m95j20Z7Bm>
   Via: SIP/2.0/UDP;branch=z9hG4bKf51e.37f620408d52cf8e36d86949cd3313b7.0
   Via: SIP/2.0/UDP;received=;rport=11000;branch=z9hG4bKgg3…
   Max-Forwards: 48
   From: "21995498" <>;tag=N56m95j20Z7Bm
   To: <>

SIP Trunk Configuration

When adding numbers to CVS SIP Trunk on 3CX the DDIs are typically added “64x xxx xxxx” ..

The SIP Trunk will look like:

When selected the full list of DDIs can be viewed:

As VVP SIP Trunk uses the international standard E.164 format. This means that a leading “+” is inserted as a prefix.  This change in format would cause calls to fail to identify an inbound route.   However, it is possible to configure 3CX to seamlessly support both the CVS and VVP formats.  This means that come migration time, the service can be moved transparently, without service interruption.

The simple addition of a ‘*’ prefix on the DID/DDI Number means that 3CX will accept and route numbers on both platforms.

The above DIDs now become

Once the change is made to the numbers under the SIP Trunk, the new format is automatically reflected in the Inbound Rules


 3cx Trunks on VVP.docx (130.54 KB)