Sip-Nat Interoperation - Linksys SPA9000 Administration Manual

Architectural Component
SIP proxy and Registrar server
Media proxy server
Configuration server
Application server
Internal music source
Administration web server
ATA with 2 FXS ports
Call park
Auto-Attendant

SIP-NAT Interoperation

If the SPA9000 is behind the NAT device, the private IP address of the SPA9000 is not usable for
communications with the SIP entities outside the private network.
If the ITSP offers an outbound NAT-Aware proxy, this discovers the
Note
public IP address from the remote endpoint and eliminates the need to
modify the SIP message from the UAC.
The SPA9000 system must substitute the private IP address information with the proper
external IP address/port in the mapping chosen by the underlying NAT to communicate with a
Linksys Voice System Administration Guide
Table A-1 Architectural Components
Function
Accepts registration from client stations and
proxies SIP messages.
Proxies RTP packets between client stations
and proxies SIP messages.
Serves configuration files to client stations
and auto configures un-provisioned client
stations.
Supports advanced features such as call
park/pickup, directory, directed call pickup
and group paging, hunt groups, and shared
line appearances.
Streams audio files to client stations (both
on-net and off-net).
The FXS1 and FXS2 can optionally be
connected to an external music source to act
as a streaming audio server (SAS). When
working in this mode, each FXS port can
handle up to 10 concurrent calls.
Allows configuration and monitoring of the
SPA9000.
Each FXS port can be connected to analog
phones, fax machine, or an external music
source. Each port can support up to two calls
simultaneously. The FXS ports can only
register to the internal proxy server.
The call park is used to maintain calls that are
parked and can handle up to 10 calls
simultaneously
AA is a scriptable auto-attendant application
that can handle up to 10 calls simultaneously
SIP-NAT Interoperation
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