Product and Software: This article applies to the Cisco/Linksys WIP310.
In a customer premises, a SIP-based WiFi phone works well (on our Aruba wireless network) if the user does not move around the building. As the user moves around the building (presumably hopping from access point to access point), the call becomes scrambled and eventually terminates even though the building has an excellent coverage.
Upon troubleshooting, we found this to be a client issue. The particular VOIP/WIFI phone is a Cisco/Linksys WIP310 and it does not support inter-ap roaming while a call is in progress.
However, the Cisco 7900 series does not have this limitation; we use it internally over our Aruba infrastructure with no problems.
From a marketing perspective, you have to look closely to find the fine print on this page:
"Simultaneous, active calling and Wi-Fi roaming between access points is not supported."
The phone locks to a particular BSSID while a call is in progress.