Polycom Video Game Sound System Version 2.0.3B User Manual

Page of 42
Technical Bulletin
SoundPoint 
®
 IP, SIP 2.1
3
SIP 2.1 Server Fallback Implementation
In the SIP 2.1 release, the redundancy behavior of Polycom SoundPoint IP and 
SoundStation IP phones has been changed and improved by adding the ability 
for a single SIP Registration (Line) to be registered to more than one server 
concurrently. In previous releases, the phone would only maintain one active 
server registration per SIP Registration (Line). The concurrent server 
registration capability adds an ability to do a faster and more efficient 
hand-over to an independent call server both for incoming as well as outgoing 
calls.
To assist in explaining the redundancy behavior, an illustrative example of 
how a system may be deployed is defined in the following section.
Example Deployment
A small medium business (SMB) customer uses a hosted IP-Centrex service 
from a Service provider. The Service provider has two redundant call servers 
at their network operations center (NOC) and uses a DNS server to resolve the 
IP addresses of these servers. The SMB customer also has an on-premise router 
which has the ability to handle SIP call traffic and has a connection to an 
on-site PSTN gateway. This gateway is intended to be used in conditions in 
which the Internet connection to the service provider is not working.
 
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PSTN Gateway
Internet
PSTN
Hosted VoIP Service 
Provider
VoIP SMB Customer 
Premise
DNS Server
Call Server 1A
Call Server 1B
SIP Capable Router
Server2