Routers And Service Provider Support Of Nat; Session Border Controllers - Linksys SPA922 Administrator's Manual

• "Session Border Controllers" section on page 12
• "Simple Traversal of UDP Through NATs (STUN)" section on page 13
• "SIP-NAT Interoperation" section on page 13
• "Determining the Type of NAT Used on Your Router" section on page 14

Routers and Service Provider Support of NAT

NAT allows multiple devices to share the same public, routable, IP address for establishing
connections over the Internet. A router forwards packets between the Internet and the internal,
private network.
NAT mapping is the association between a private address and port and a public address and
port . The mapping is maintained for a short period of time, varying from a few seconds to
several minutes. The mapping time is extended when a source device sends a packet.

Session Border Controllers

The service provider can support NAT mapping using a session border controller. With a session
border controller, you do not have to manage NAT on the SPA9x2.
If the service provider does not support session border control, use the NAT Support
Parameters provided by the SPA9x2, such as:
• Outbound Proxy (see
• STUN Server Enable (see
• EXT IP
Linksys SPA9x2 Phone Administration Guide
Introducing Linksys SPA9x2 Phones
Network Address Translation and SPA9x2 Phones
"Proxy and Registration Parameters" section on page
"NAT Support Parameters" section on page
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