Symptom

We are upgrading isr4331 and isr4321 VZW 4G routers from 16.12.4 to 16.12.5 code. Once on 16.12.5, profile 3 will not establish with the PDP Type set to IPv4v6 and the tunnel will not come up.

Conditions

If I leave it where VZW sets it to IPv4v6 via the APN it will not work. Also if I put in "cellular 0 lte profile create 3 none ipv4v6" and reload the router it will not work and continue to get the following error: router#Cellular0/1/0: drop chat, v4v6 session disconnect in progress 0 router#Cellular0/1/0: drop chat, v4v6 session disconnect in progress 0

Workaround

If the customer changes the profile PDP type to just IPv4 everything works correctly..

Further Problem Description