Configuring Your System for ITSP Interoperability

3

 

About the SPA9000 Voice System and SIP

 

 

 

 

 

Figure 1 SIP Requests and Responses for Internal Calls

SIP UA

2

4

SIP Proxy

RTP

SIP Proxy

3

SIP Proxy

1

SIP UA

Likewise, SIP requests and responses are exchanged to support outbound and inbound calls that are handled through the ITSP service. In Figure 2, “SPA9000 as a SIP Proxy for Internet Calls,” UserA and UserB are client stations that are registered to the SPA9000. When UserA calls UserC, the SPA9000 directs the request to the SIP proxy at the ITSP, which is then responsible for routing the request to UserC. After the session is established, RTP is anchored by the SPA9000.

Figure 2 SPA9000 as a SIP Proxy for Internet Calls

UserC

UserA

UserB

Hub/switch

IP Router (firewall)

Broadband modem

 

ISP

Internet (WAN)

Interface

Internet

SPA9000

SIP Proxy with

media proxy enabled

ITSP

SPA9000 Voice System Administration Guide

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Cisco Systems SPA9000 Configuring Your System for Itsp Interoperability, SIP Requests and Responses for Internal Calls