Nat Traversal Feature - Avaya Nortel Communication Server 1000 Manual

NAT Traversal feature

Network Address Translation (NAT) provides the following benefits:
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A NAT device (router) exists between a private network and a public
network. The NAT device maps private addresses to public addresses.
With the NAT Traversal feature, several IP Phones are now supported
behind a single Cone NAT router with, or without, Virtual Private Network
(VPN) capabilities. This support enables large-scale deployment of Voice
over Internet Protocol (VoIP) in teleworking and Small Office/Home Office
(SOHO) environments.
Supported Cone NAT routers include:
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A Cone NAT router with more than one IP Phone connected to it must support
hairpinning. Hairpinning occurs when an IP Phone behind a NAT router can send
packets to the Public IP address and port of another IP Phone connected to
the same NAT router.
Symmetric NAT routers are not supported. If the IP Phone is behind a Symmetric
NAT, IP Phone registration is unsuccessful and the IP Phone displays a "NAT
Error! ITG3053" message.
Echo Servers
NAT Traversal is a function of the CS 1000 Release 4.5 or later software,
and not a function of the NAT router. NAT Traversal uses two Echo Servers
residing on the Signaling Server. Echo Server 1 detects the presence of
a NAT router, while Echo Server 2 detects the type of NAT router. Both
Echo Server 1 and Echo Server 2 are required for the NAT Traversal feature
to function properly.
Copyright © 2003–2008, Nortel Networks
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the ability to network multiple sites with overlapping private address
ranges
added security for servers on a private network
conservation of public IP address allocation
Full Cone
Restricted Cone
Port Restricted Cone
Nortel Communication Server 1000
IP Line Fundamentals
NN43100-500 02.02 Standard
Release 5.5 4 February 2008
NAT Traversal feature 117
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