We have a separate network set aside for our IP phones. The only thing beside the phones is a server to log into the phones through http. There are potentially 60 (48 plugged in right now) phones, each of which registers via SIP to a remote server. Most of the phones are SPA 508G but some are SPA 525G. We have a SG500-52P-K9-NA switch, connected to a RV180-K9-NA router. We are on a cable modem connection with 35 mbps DL speed and 5 mbps UL speed. Right now, as we connect new phones, some of the old phones deregister. When we then take these phones and plug them into a different network, by themselves, they re-register. We plug them back into our network, and then a different phone deregisters. I ran wireshark and got some 401 Unauthorized responses on SIP. But since the phones are re-registering when plugged into a solitary network, clearly the authentication parameters are correct. Could it be bandwidth? Perhaps a firewall issue? There seems to be no clear pattern as to which phones will deregister. EDIT: I have added the packet captures from wireshark.
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