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Cisco VISM Installation and Configuration Guide
Release 3.0, Part Number OL-2521-01 Rev. D0, June 2004
Chapter 1 Overview of the VISM and VISM-PR Cards
VISM and VISM-PR Card Features
• Voice over ATM (VoATM) using AAL2 cells—No Logical Link Control/Subnetwork Access
Protocol (LLC/SNAP) encapsulation.
Note Multiplexing is not supported for AAL2 SVCs.
• VoIP using AAL5 cells to RFC 1889.
• Extended Superframe (ESF) framing with or without cyclic redundancy check (CRC).
• Pulse code modulation (PCM) A/Mu law codecs.
• Programmable 24, 32, 48, 64, 80, 96, 112, 128 ms tail delay near end ECAN.
• Voice compression with the following standards:
–
G.711
–
G.726-16k
–
G.726-24k
–
G.726-32k
–
G.726-40k
–
G.729a
–
G.729ab
–
G.723.1-H
–
G.723.1a-H
–
G.723.1-L
–
G.723.1a-L
Note The G.723.1 codecs are not supported in combination with the VISM card. The G.723.1
codecs are supported with the VISM-PR card.
• Nx64 clear channel (N = 1 only) support.
• Voice activity detection (VAD) and comfort noise generation (CNG) using variable threshold energy
(Cisco proprietary).
• Call agent Simple Gateway Control Protocol (SGCP) Version 1.0, 1.1, 1.5, SGCP 1.1+, 1.5, and
Media Gateway Control Protocol (MGCP) 0.1 and 1.0.
• Backhauling channel associated signaling (CAS) signaling to a call agent using xGCP (backhauling
can be accomplished with any supported SGCP and MGCP protocol).
• Backhauling Primary Rate Interface (PRI) signaling via Reliable User Datagram Protocol (RUDP)
to a call agent.
• Common channel signaling (CCS) transport across an AAL5 trunk.
• Fax and modem VoIP bearer transmissions.
• Dual (redundant) virtual circuits across the packet network.
• Full continuity testing (COT). Supports origination and terminating loopback and transponder COT
between VISM and the central office on the TDM side.
• Loop timing, which can be used as the master clock for the entire MGX 8000 Series platform and
local clock.