Specifications

4-12

Cisco IOS Telephony Service, Version 2.02

Chapter 4 Advanced Configuration Tasks

Integrating Voice Mail

MWI Mechanism

The MWI mechanism is initiated after someone leaves a voice-mail message. The internal MWI

mechanism of the Cisco IOS Telephony Service router is explained in Figure 4-6.

Figure 4-6 MWI Mechanism

In the network topology in Figure 4-6, the following events take place:

1. The Cisco IP phone with the extension 2001 receives a call and the call is not answered.

2. The Cisco IP phone with the extension 2001 forwards the call to the voice-mail access port 4001.

3. The Cisco Unity Voice Mail system (extension 4001) stores the new message for extension 2001.

4. The Cisco Unity Voice Mail then places an MWI notification call to the MWI processing ephone-dn

8000 (through the MWI access port 4002) with the calling party ID for the notification call set to

2001.

5. The Cisco ITS DN 8000 accepts the MWI notification call and switches on the message waiting light

for extension 2001.

The Cisco IOS Telephony Service router can convey MWI information to the Cisco IP phone DNs if the

Cisco IP phones are associated with the router.

If the Cisco IP phones are not associated with the Cisco IOS Telephony Service router connected to the

Cisco Unity Voice Mail system, the MWI information is conveyed by using the MWI relay feature. For

further details, see the “Configuring MWI Relay” section on page 4-16.

When a voice-mail system has MWI information for any extension local or remote, it dials the central

site Cisco IOS Telephony Service router. When the central site receives the MWI information, it attempts

to find out whether the extension is local to the central site. If it cannot find the extension, it passes the

MWI information to its notifier interface of SIP MWI. If the notifier interface on central site has the

extension as a subscriber, it relays the MWI information to the remote Cisco IOS Telephony Service

router.

PSTN

2001

Cisco Unity

Voice Mail

4001

Cisco CallManager Express

62701

Voice-mail

access DNs

4001(voice calls)

MWI

8000

8001

4001(voice calls)

4002(MWI only)

4 ports created for voice mail

10.10.12.1

ephone

2001