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Cisco IP Telephony Network Design Guide
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Chapter 10 Migrating to an IP Telephony Network
Simple IP Network Migration Sequence
While conventional voice networks use proprietary, closed protocols internally,
they can be connected to IP networks only through open protocols. This would
also be the case when networking equipment from different vendors. PRI (or
QSIG) between PBXs, analog Simplified Message Desk Interface (SMDI)
between PBXs and voice mail systems, and Audio Messaging Interchange
Specification (AMIS) between voice systems are the most powerful interfaces
available.
Simple IP Network Migration Sequence
The following three figures illustrate the phases in migrating from a conventional
voice network to an all-IP system. Figure 10-2 shows the initial conventional
voice network.
Table 10-1 Interfaces and Protocols for PBX and Voice Mail System Networking
Vendor PBX to PBX Protocols
PBX to Voice Mail
Interfaces
Voice Mail to Voice Mail
Networking
Cisco PRI, QSID, CAS SMDI, analog AMIS-A
1
1. Cisco supports AMIS-A on Cisco uOne beginning with release 5.0E.
Avaya PRI, DCS, QSIG Digital set emulation
Proprietary,
X.25/C-LAN
Octelnet
AUDIX Digital Networking
AMIS-A
Nortel PRI, MCDN, DPNSS,
QSIG
Proprietary (IVMS) Meridian Mail Networking
VPIM
AMIS-A
Siemens PRI, CorNet, DPNSS,
QSIG
BRI with proprietary
extensions
PhoneMail Long Distance
Networking (LDN)
AMIS-A
Alcatel PRI, ABC, QSIG unknown unknown
NEC PRI, CCIS, QSIG Proprietary Message
Center Interface (MCI)
unknown
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