Cisco Unity Deployment and Solutions Guide

46 Chapter 2: Unity Architecture Overview

Unity system cares about. In short, Unity cares about any Exchange server that houses one

or more subscribers on it. These Exchange servers are added to the list of systems that the

windows manager pings every 15 seconds (in versions 3.1[3] and earlier, this was every

30 seconds). If the server is offline or the Exchange directory (in the case of Exchange 5.5)

or mail store services (for both Exchange 55 and 2000) are not responsive, or if the Service

Control Manager (SCM) itself is not responsive, this server is marked internally as being

down. When a subscriber signs into the Unity server over the phone to gain access to

messages, the conversation first checks to see whether that Exchange server is up or down

before attempting to log into that user’s mailbox. If it is down, subscribers are not allowed

to attempt the login to their mailboxes over the phone because this can result in very

long MAPI timeouts and can end with a call being stuck or “wedged” for a long period

of time. If the Exchange server that you selected during the configuration setup (the partner

Exchange server, as it is called in the documentation) is offline, Unity goes into full UMR

mode and stores voice messages locally until connectivity can be re-established.

In the case of Domino, the monitoring service cannot assume that the server is running on

top of a Windows platform, so things get a little trickier. The service simply pings the server

by name and checks for a response to make sure it is up. It does not, however, know whether

the Domino services on that server function properly.

Whenever the avWM component marks a server as being down or back up again, an event

log message is written through to the application event log. The Event Monitoring Service

(EMS) Exchange Monitor Tool introduced for Unity 4.0(2) resides in the Tools Depot. It is

designed to give the administrator the capability to be notified in a variety of ways when

specific errors or classes of errors are written to the event log. For sites that have trouble

with their external Exchange servers or that experience severe network latency issues, this

can be helpful in staying on top of such problems.

AVNotificationMgr

For the Unity 4.0(3) release, the notification processes that are responsible for lighting

MWIs, sending out notification e-mails, sending pages, and so on based on inbox activity

have been pulled out of the AVCsMgr group into their own process here.

Notifier

What is referred to generally as “the notifier” is actually a set of three separate components.

The AVMsgStoreMonitorSvr (see the upcoming section with this name) watches all inboxes

of subscribers on the local Unity server for changes and then pushes that information onto

the notification queue. The notifier engine in the AVNotificationMgr process watches the

queue for items that it needs to react to and hands off the request to one of four device man-

agers for MWIs, SMTP (text pagers), conversations (phone notification device), or pagers