This is not a question, but an answer to an issue we found during an upgrade of our 7k's from 6.1(4)a to 7.2(0)D1(1).
I wanted there to be a record of it since it's a pretty obscure issue, and I couldn't find a resolution for about a week. During which time our Spectralink 8020/8030 phones were not working, which is a critical problem for us.
Spectralink phones were working fine prior to the upgrade. After the upgrade, they were showing "No SVP response" and "No GW response". Basically, they couldn't talk to their SVP server in order to get their extensions from their gateway.
We finally found Spectralink Technical Bulletin CS-04-10 , which pertains to 6k's, but worked here as well.
Apparently something changes with IGMP in the new code, and I had to set the following on our 7k's:
(config) ip igmp snooping
(config) vlan configuration 59 <this is our Spectralink wireless network>
(config-vlan-config) ip igmp snooping querier <ip address of SVP server>
For good measure, I set ip igmp snooping globally on our 6k's as well.
I don't know if all of the above is necessary, but when I finished, they started working, so I didn't change anything.
Hope this helps.