Cisco Systems 5.x Phone System Considerations for Cross-Server Features, Feature Description

Chapter 3 Cross-Server Logon, Transfers, and Live Reply

Overview of Cross-Server Logon, Transfer, and Live Reply

Table 3-1	Cross-Server Features
Feature		Description
Cross-server logon		Cross-server logon allows administrators to provide subscribers who are
		homed on different Cisco Unity servers in the same dialing domain with one
		phone number that they can call to log on to Cisco Unity. When calling from
		outside the organization to log on to Cisco Unity, subscribers—no matter
		which is their home Cisco Unity server—call the same number and are
		transferred to the applicable home Cisco Unity server to log on.
Cross-server transfer		Cross-server transfer enables calls from the automated attendant or from a
		directory handler of one Cisco Unity server to be transferred to a subscriber
		on another Cisco Unity server in the dialing domain, according to the call
		transfer and screening settings of the called subscriber.
Cross-server live reply		Cross-server live reply allows subscribers who listen to their messages by
		phone to reply to a message from a subscriber on another Cisco Unity server
		in the dialing domain by calling the subscriber (according to the call transfer
		and screening settings of the called subscriber).

Although the cross-server features are distinct features, they all use the same underlying functionality—an enhanced supervised call transfer:

1.The Cisco Unity server on which a logon, transfer, or live reply originates puts the caller on hold and calls the home Cisco Unity server.

2.When the destination Cisco Unity server answers, the originating Cisco Unity server sends a sequence of DTMF tones that identify the call as a cross-server logon, transfer, or live reply.

3.The destination Cisco Unity server responds with a sequence of DTMF tones, and the originating Cisco Unity server hands off the call to the destination server for processing.

4.At this point the functionality is the same as though the call had originated on the home Cisco Unity server.

In this chapter, an originating Cisco Unity server is defined as a server that calls other Cisco Unity servers. A destination Cisco Unity server is defined as a server that answers a cross-server call.

Phone System Considerations for Cross-Server Features

The cross-server features are supported for integrations with Cisco Unified Communications Manager (CM) (formerly known as Cisco Unified CallManager), integrations with phone systems through PIMG/TIMG units, and/or integrations with Cisco SIP Proxy Server (CSPS). Integrations with phone systems through voice cards are not supported.

The following factors can contribute significantly to delays in cross-server call handoff:

•Longer subscriber extensions. A four-digit extension does not take as long for Cisco Unity to dial as a ten-digit extension.

•Longer dialing strings to reach the destination Cisco Unity server. A four-digit dialing string does not take as long for Cisco Unity to dial as a ten-digit dialing string.

•Multiple elements (such as PIMG/TIMG units, voice gateways, TDM trunks, and PSTN interfaces) in the call path between the originating Cisco Unity server and the destination Cisco Unity server. More elements in the call path require more processing time for handing off cross-server calls.

Networking Guide for Cisco Unity Release 5.x (With Microsoft Exchange)

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