Polycom SIP 3.1 manual Phone Configuration, Phone Operation for Registration

Configuring Your System

Hosted VoIP Service

Provider

Call Server 1B

Call Server 1A

DNS Server

Internet

PSTN

Phone Configuration

	VoIP SMB Customer
SIP Capable Router	Premise
Server2
	`
	`
PSTN Gateway
	`
	`

The phones at the customer site are configured as follows:

•Server 1 (the primary server) will be configured with the address of the service provider call server. The IP address of the server(s) to be used will be provided by the DNS server. For example:

reg.1.server.1.address="voipserver.serviceprovider.com"

•Server 2 (the fallback server) will be configured to the address of the router/gateway that provides the fallback telephony support and is on-site. For example:

reg.1.server.2.address=172.23.0.1

Note	It is possible to configure the phone for more than two servers per registration, but
	you need to exercise caution when doing this to ensure that the phone and network
	load generated by registration refresh of multiple registrations do not become
	excessive. This would be of particularly concern if a phone had multiple
	registrations with multiple servers per registration and it is expected that some of
	these servers will be unavailable.
	Phone Operation for Registration
	After the phone has booted up, it will register to all the servers that are
	configured.
	Server 1 is the primary server and supports greater SIP functionality than any
	of servers. For example, SUBSCRIBE/NOTIFY services (used for features such
	as shared lines, presence, and BLF) will only be established with Server 1.
	Upon registration timer expiry of each server registration, the phone will
	attempt to re-register. If this is unsuccessful, normal SIP re-registration
	behavior (typically at intervals of 30 to 60 seconds) will proceed and continue

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