Re: Linksys with Cisco 7960

[Andrew Millson <>]

What exactly are you trying to do?

One of the issues with VoIP is that it does not play well with NAT. If 
you are trying to use you 7960 through a NAT firewall you will not have 
 a lot of luck. The biggest problem is that the phone encapsulates the 
IP address on the local private net (192.168.xxx.yyy, 10.xxx.yyy.zzz) 
inside the data packets that are sent to the Call Manager rather than 
using the public IP address of the router. When the call manager 
receives the registration of the phone it uses this private IP address 
as the destination address of the IP Phone. When you try to use the 
phone the call manager will use this private IP address to try to talk 
to the phone and will fail across the public internet. If you check the 
Call Manager for registered phones you will see that the extension in 
question has registered with a private IP address.

You need a VoIP aware Router that will inteligently query the packets 
and rewrite the IP address of the VoIP packets to have the correct IP 
address. I am unaware of a Linksys box that does this, but am willing 
(and would be VERY happy to hear from others who have solved this issue).

If you are using a VoIP aware NAT Router then I'm not sure what your 
problem is and hopefully someone else on the list can help.

When using most SIP User Agents (including the Cisco 7960 with the SIP 
load) you can usually configure the phone to use the public IP address 
of the NAT'ing router rather than the private address,  or use a STUN 
server which will do the same thing and saves you having to find your 
public IP address, which often changes.

Andy

Abeysekera, Buddhi Indika wrote:
> I would like to know if anyone has got any Linksys routers (wireless or
> wired with Linksys firmware) to work with a Cisco 7960 (skinny load)
> phone using Cisco Call Manager. If so, please let me know the model and
> firmware version of the Linksys router used.
>  
> Thank you for your help.
>  
>
> Buddhi Abeysekera 
> Information Technology - Telecommunications 
> University of Miami 
> Email:  
>
>  

--
Andrew Millson
Telecommunications and Networking Services
University of Iowa

Tel   : 319 335 6159
Email :