sundance-communications.com/forum Forums TDM Business Telephone Systems NEC Telephones & Systems 8100 IP Phone Problem

We installed a 8100 with 4 remote IP phones with NAT routers (with the Tomato program) about a week ago. The IP phones reset about every 15 to 20 minutes. Sometimes all four, sometimes 1 of the IP phones, two of them.... The phones work, incoming/outgoing, until of course the phones reset. It will say on the display "Network Busy" or something like that. The IT people say the routers are fine. I did a path ping test when the IP phones reset and there was 0% loss. We are using Dynamic addresses. We installed data cables to each phone so we are not on the customer's network, separate dsl connection at each site with NAT routers. The 8100 and IP phone programming looks fine, but obviously we are missing something.

Any ideas?

Are the fones running fix IP or DHCP?? Have not seen much NAT down here but i setup one at home the other nite to test with.

Did you set these up as per Mr Suff's cheat sheet??

Any line lengths exceed cat 5/5e/6 standard?

Any cables run parallel to fluorescent fixtures?

Any unattended data cabinets near people who have to tinker with flashy lights?

Try moving one of the phones to the router, and see if it happens there. If so, Router/DSL is the problem. If not, work backwards one switch at a time until the problem recurs.

Also, you might want to confirm that you don't have a bad batch of phones...

I remember hearing something about disabling SIP ALG in the router if you run into this problem. I think it is in the firewall section.

Thank you for your help everyone. We tried what you said, and unfortunately we could not resolve the issue. We ended up removing the NAT routers and installing VPN routers and changing the 8100 programming to remove NAT. Problem gone, IP phones OK. Will be testing NAT in our office before we try installing it again at a customer's site.
Thanks.