Aastra VentureIP 480i, Administrator'S Manual, Page: 23 / 174

16 IP Phone SIP Admin Guide
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Advanced Network Settings
You can set advanced network settings on the IP phone such as, Network
Address Translation (NAT), Virtual LAN (VLAN), and Quality of Service
(QoS), using the IP phone UI, the Aastra Web UI, or the configuration
files.
Network Address Translation (NAT)
The protocols used by all IP phones do not interoperate completely with
Network Address Translation (NAT). For the Aastra IP phones, specific
configuration parameters allow the phone to operate while connected to a
network device that enforces NAT. The following is a sample network
using a NAT proxy and relevant IP phone configuration parameters.
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.
Note: This IP phone uses RTP port 3000
(the default value) since an RTP
port was not explicitly config-
ured.
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.