Cisco Systems MGX 8230 manual T3 Interfaces via SRM Bulk Distribution

Chapter 2 Module and Service Descriptions

Frame Relay Service Modules

T3 Interfaces (via SRM Bulk Distribution)

T3 interfaces are supported using the SRM’s bulk distribution capability. In this case, the T3 interfaces are physically terminated at the SRM module. The SRM module breaks out the individual T1s and distributes the T1s via the TDM backplane bus to the individual VISM cards for processing.

Echo Cancellation

The VISM provides on-board echo cancellation on a per-connection basis. Up to 128 msec user-configurable near-end delay can be canceled. The echo cancellation is compliant with ITU G.165 and G.168 specifications.

Voice Activity Detection (VAD)

VISM uses VAD to distinguish between silence and voice on an active connection. VAD reduces the bandwidth requirements of a voice connection by not generating traffic during periods of silence in an active voice connection. At the far-end, comfort noise is generated.

Fax/Modem Detection for ECAN and VAD Control

The VISM continually monitors and detects fax and modem carrier tones. When carrier tone from a fax or modem is detected, the connection is upgraded to full PCM to ensure transparent connectivity. Fax and modem tone detection ensures compatibility with all voice-grade data connections.

CAS Tunneling via AAL2 (For AAL2 Trunking Mode)

The VISM in AAL2 mode facilitates transport of CAS signaling information. CAS signaling information is carried transparently across the AAL2 connection using type 3 packets. In this mode, VISM does not interpret any of the signaling information.

PRI Tunneling via AAL5 (For AAL2 Trunking Mode)

VISM supports transport of D-ch signaling information over an AAL5 VC. The signaling channel is transparently carried over the AAL5 VC and delivered to the far-end. In this mode, VISM does not interpret any of the signaling messages.

Voice CAC

VISM can be configured to administer Connection Admission Control (CAC) so that the bandwidth distribution between voice and data can be controlled in AAL2 mode.

Type 3 Packet for DTMF

The VISM in AAL2 mode facilitates transport of DTMF signaling information. DTMF information is carried transparently across the AAL2 connection using type 3 packets.

Dual (Redundant) PVCs for Bearer/Control

The VISM provides the capability to configure two PVCs for bearer/signaling traffic terminating on two external routers (dual-homing). VISM continually monitors the status of the active PVC by using OAM loopback cells. Upon detection of failure, the traffic is automatically switched over to the backup PVC.

64 K Clear Channel Transport

The VISM supports 64 Kbps clear channel support. In this mode, all codecs are disabled and the data is transparently transported through the VISM.

DTMF Relay for G.729

In VoIP mode, DTMF signaling information is transported across the connection using RTP NSE (Named Signaling Event) packets

	Cisco MGX 8230 Edge Concentrator Installation and Configuration
2-56	Release 1.1.31, Part Number 78-11215-03 Rev. B0, May 2001