Specifications

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Cisco IP Telephony Network Design Guide
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Chapter 10 Migrating to an IP Telephony Network
Reference Models for Migration Configurations
The following list summarizes the pros and cons of the type B system:
Detailed Discussion of Model C
Figure 10-8 shows the topology for model C, which includes a PBX and voice
messaging, with extra SMDI and analog links from the voice messaging system
directly to the IP network.
Figure 10-8 Model C—PBX and Voice Messaging System with Separate Links to
the IP Network
The considerations for telephony features for model C are the same as for
model A.
Pros Cons
• IP users get access to voice
messaging as they migrate from
the PBX.
• Relatively inexpensive to
implement
• Same voice feature shortfall as
type A systems
• No MWI support for IP users
• Workaround entails administration
complexity and possibly PBX
hardware.
PSTN
PBX LAN
Migration
Voice
messaging
system
V
V
IP
IP
IP
SMDI
Analog
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