7925 Phones Register in one site, not another - Same WLAN

[jim.stengle]

I have 7925 wireless phones that register when in one building - same WLAN, different IP subnet, but not in another. However, at least one phone is able to register at each location. No phones appear to register in both sites. The buildings are adjacent to each other.

They are using the same WLAN configuration across both buildings. Phone A connects to the WLAN in building A and gets an IP address in subnet A and registers to CUCM. Phone A goes to building B and connects to WLAN and gets an IP address in subnet B but does not register.

However Phone B connects to the WLAN in building B and gets an IP address in subnet B and registers to CUCM. Phone B goes to building A and connects to WLAN and gets an IP address in subnet A but does not register. 

I know CUCM is good. I have rebuilt the profiles and reset the phones. Phones connect to wireless and get DHCP successfully. I see unable to resolve DNS entries, although we have added PTR records for cucm01 as well as cucm01.domain.com for each CUCM server. 

[Deven Gandhi]

Are phones in building A registering to same CM Cluster as in building B?  Have you tried deleting ITL file and downloading new one?

-Deven Gandhi
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[jim.stengle]

Deven,

The phones are all registering to the same cluster in both buildings. I have not tried deleting the ITL file because it is the same cluster. 

Thanks,

Jim

[Deven Gandhi]

Since you are using same voice vlan ID in both buildings with two different subnets, how are two building connected and communicate with CUCM?  Does building A had it's own WAN router and building B has it's own with two different ISP connection?  Or two buildings are uplinked via fiber or copper?

-Deven Gandhi
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[Jonathan Schulenberg]

This sounds like a wireless issue and you may get better support in that community. For example, are you using Flex Connect / H-REAP or a CAPWAP tunnel from the APs to the controller? If the later, have you vericied that layer three roaming is working properly? I'm not a wireless engineer but I have done several projects with the 7925 phones... The wireless considerations are no small matter, especially in a campus because of the inherent roaming features of the SSID. In one project we had to create a separate SSID per-building to prevent the controller from anchoring the client in the original VLAN which broke Device Mobility and thus [rudamentary] E911.