Aastra Telecom SISIP 57I CT - Manual (Page 85)

Advanced Network Settings
41-001160-00, Rev 01 Release 2.0 4-19
Network Configuration of the IP Phones
Configuring the IP Phones Nortel Proxy/Registrar
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.
SBC or ALG proxy/registrar
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.
Other proxy/registrars
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.
NAT router configuration
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.
Note: This IP phone uses RTP port 3000 (the default value) since an RTP
port was not explicitly configured.