Aastra Telecom C53I User Guide

Advanced Network Settings

41-001160-00, Rev 01  Release 2.0

4-19

Network Configuration of the IP Phones

The phone at IP address 10.10.10.10 is configured to register with the proxy at 
63.251.195.10. Because it is a Nortel proxy, the configuration must additionally 
include the "sip nortel nat support" and "sip nortel nat timer" settings, telling the 
firmware to enhance the protocols with Nortel specific content.

The phone at IP address 10.10.10.20 is configured to register with the proxy at 
63.251.195.20. Because the proxy/registrar has session border control (SBC) or 
application layer gateway (ALG) functionality, no additional IP phone 
configuration is required. 

The phone at IP address 10.10.10.30 is configured to register with the proxy at 
63.251.195.30. Because this proxy/registrar is not a Nortel proxy and has no SBC 
or ALG functionality, the configuration must additionally include the "sip nat ip" 
and "sip nat port" settings that contain the public ip address of the NAT router and 
the port used for call signaling messages. This information is embedded in 
protocol messages to allow the proxy/registrar to reach the IP phone on the NAT 
router private network.  

You must configure the NAT router to allow signaling or media packets 
containing the various UDP port values to flow between the private and public 
networks that are separated by the NAT router. In the sample network, the NAT 
router must not filter packets using ports 3000, 5060, 6060, 16420, and 16430. 

This IP phone uses RTP port 3000 (the default value) since an RTP 

port was not explicitly configured.