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Networking Guide for Cisco Unity Release 5.x (With Microsoft Exchange)
OL-13844-01
Chapter 3 Cross-Server Logon, Transfers, and Live Reply
Overview of Cross-Server Logon, Transfer, and Live Reply
In your environment, these factors can create delays that may cause the cross-server features to be
unusable or unfeasible for callers. You must test your cross-server configuration on a representative call
path in your environment to determine whether the delays that callers experience are acceptable.
Planning for Increased Port Usage
The cross-server features require the use of ports on both the originating and destination Cisco Unity
servers. Depending on how busy your Cisco Unity servers are, you may need to add more ports or an
additional Cisco Unity server before enabling these features. You may also need to adjust how ports are
configured. For example, you may need to enable more ports to accept incoming calls.
After enabling the cross-server features, we recommend that you monitor activity on the Cisco Unity
servers closely until you are confident that the servers can handle the increased load. You can use the
Port Usage Analyzer for this task. The Port Usage Analyzer is available in the Report Tools section of
Tools Depot. See Port Usage Analyzer Help for detailed instructions. Be sure to monitor the Windows
Event Viewer on both the originating and destination Cisco Unity servers for event log messages related
to problems with ports.
A Brief Look at Cisco Unity Data Architecture
To understand why the cross-server features are needed, it is helpful to have a basic understanding of
Cisco Unity data architecture. Cisco Unity stores information about subscribers (and other Cisco Unity
objects such as call handlers) in a SQL Server database on the Cisco Unity server. A small subset of
information about subscribers, distribution lists, and location objects is also stored in Active Directory.
Because all of the Cisco Unity servers access the same global directory, each Cisco Unity server has
access to the information stored in the directory by other Cisco Unity servers. When subscriber,
distribution list, and location data from other Cisco Unity servers replicates in the directory, each
Cisco Unity server detects the data and updates its local SQL Server database.
The data that is stored in the directory is limited to just what is needed to provide basic Digital
Networking functionality:
• Messaging between subscribers homed on different Cisco Unity servers.
• Release to switch call transfers from the automated attendant or directory handler to subscribers on
different Cisco Unity servers in the dialing domain.

Why Cross-Server Logon Is Needed

Without cross-server logon, subscribers have to call the specific Cisco Unity server they are homed on
to log on to their mailboxes over the phone. There are several reasons for this restriction:
• The subscriber conversation requires access to subscriber greetings and subscriber call handler, call
transfer, and call screening information. However, subscriber greetings and most of the other
subscriber information is stored only on the Cisco Unity server on which the subscriber account was
created. This data is not replicated across the directory because of size considerations.
• The message store services on each Cisco Unity server log on with a domain account that has the
permissions needed to access local subscriber mailboxes. If different domain accounts are assigned
to the message store facing services on other Cisco Unity servers, the message store services on one
Cisco Unity server may be unable to log on to the mailboxes of subscribers on other Cisco Unity
servers.