Yesterday was a big day for us voice geeks at work. We did both a 7.1(5) to 8.6(2a) migration on Cisco Unified Communications Manager (CUCM) and an 8.0(3) to 8.5(3) migration on UCCE. This upgrade was the last in several days of upgrades to get to the most recent releases on these products. The CUCM upgrade went well (the 8.6 install process is much different than other CUCM releases, but it’s documented well). The UCCE upgrade also went fine, well, until we started to test call routing to agents…
We use the out-of-the-box CTIOS as our agent desktop for testing. Our testers attempt to sign in as agents, and what do we see? Well it’s not what you hope for. Here is the error:
Well shoot — the error is pretty clear the issue is on CUCM. First, we are not using IPv6 in our enterprise so that’s not the issue. I check the IP Phone configuration in CUCM and verify there is no IPv6 settings enabled, nothing found.
I check the Enterprise Parameters for IPv6 on CUCM, it too has IPv6 set to False.
Well the error seems fixable and we’re not talking a back-out of the upgrades yet (albeit one of my worse fears). I ask Google — no real hits there. Next, we leverage that Cisco support contract and call our friends at Cisco TAC and see if they have seen this. I open the case online and call in to bump the severity. Yes TAC has seen this, once. Fixed within 5 minutes of getting an engineer. The engineer said she had only seen this one other time and that other time took several hours to figure out (I don’t feel so bad now).
So what’s the fix? Check your Common Device Configuration (CDC) profile settings in CUCM. You’ll spot it right away. Change the IP Addressing Mode from “IPv4 and IPv6” to “IPv4 Only”. Restart your agents phones and you’re back in business!
Testing went fine once we got the agents logged on. Considering my last TAC call was almost 7 hours long into the early morning hours, I was so happy to be home in time to pick-up some take-out for the family for dinner.
To the Cisco customer that fought this initially for hours, I salute you. I have been in that boat too and I thank you.