Nortel 1000 Configuration Manual

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Nortel 1000 Configuration Manual Manual pdf 45 page image

SIP/H.323 zones 45Off-net dialing planWhen dialing to the PSTN, the Call Server determines that the calldestination is off-net by analyzing the digits that must be preconfigured atmajor Call Servers in the network.If routed over a Virtual Trunk, a request is sent to the NRS to determinethe location of public E.164 numbers. The NRS is configured with a listof potential alternate routes that can be used to reach a certain dialednumber. Each route is configured with a unique route cost to determinethe least-cost route.The NRS replies with the address information for E.164 numbers. It alsoprovides a list of alternative SIP or H.323 endpoints, sorted by cost. If aterminating endpoint resource is busy when a call attempt is made, theoriginating endpoint tries the next alternative. If no alternative is availableover the IP network, the originating endpoint steps to the next entry on itsroute list, which could be a TIE or PSTN alternate route.Routing callsSRG user call to an SRG PSTNThe SRG user telephone is registered at the main office. The SRG usertelephones are physically located at the branch office, so routing of localPSTN calls back to the branch office is essential, even if they are registeredwith the main office.Branch office behavior of the SRG user telephones at the main office isconfigured by setting branch office zone characteristics through LD 117 atthe main office.SRG PSTN to an SRG telephone (DID call)If the DN is valid and can terminate, call termination at the branch office istreated differently for IP Phones and non-IP Phones, as follows:• IP Phones—If the telephone is registered to the SRG (Local Mode),the call is terminated locally. If the telephone is not registered to theSRG (Normal Mode), the call is routed through a Virtual Trunk to themain office.• Non-IP Phones—Calls are terminated locally (within the branch office).SIP/H.323 zonesIn a SIP/H.323 network, each NRS controls one SIP/H.323 zone. Eachzone can consist of many SIP/H.323 endpoints. If a call terminates beyondthe call originator zone, the SIP Redirect Server or H.323 Gatekeeper of thecalled party zone provides the endpoint information to set up the connection.Nortel Communication Server 1000Main Office Configuration Guide for SRG 50NN43001-307 02.02 StandardRelease 5.0 3 December 2007Copyright © 2005-2007, Nortel Networks.