To configure voice conference bridging on a 7705 SAR

Purpose

Perform this procedure to configure VCB on a 7705 SAR-8 or 7705 SAR-18. To support VCB, the NE must be configured with an ISC.

The VCB application provides a simultaneous communication path between two or more voice circuits. VCBs are deployed in a central location with remote devices connected to the bridge via an NE over an IP/MPLS or TDM network.

VCBs can be used as a conference bridge with any-to-any connectivity (all branches participate) or as a bridge in broadcast mode where one branch broadcasts to the other branches that are in listen-only mode.

VCB can be configured in one of four applications. These applications are set at the card level. Each application uses a bridging algorithm that determines which branches control the management of the bridge and transmission of signals:

  • VCB — One branch talks and all other branches on the bridge can hear.

  • Broadcast — Only one branch on the bridge (fixed as branch 1) has control of the bridge to transmit, and all other branches are in listen-only mode.

  • VCB Branch Initiate — Branches on the bridge are only enabled (unmuted) when the attached base station signals its presence by grounding the M-lead on the interface connected to the bridge. Upon receiving the grounded M-lead via T1/E1 ABCD bits or TDM PW signaling, the bridge unmutes the associated branch. When the ground is removed, the branch is muted again.

  • Teleprotection — Each teleprotection relay transmits state information on discrete frequencies so that each relay can both hear what the other relays are transmitting as well as transmit its own information to the other relays.

Steps
 
1 

On the equipment tree, right-click on an NE and choose Properties. The Network Element (Edit) form opens.

2 

On the NE navigation tree, expand Shelf→Card Slot n.

3 

Click the Daughter Card Slot with the Integrated Services card. The Daughter Card Slot form opens.

4 

Click on the Daughter Card tab and configure the MDA Mode parameter as VCB.

5 

Configure the VCB Application parameter. Choose one of the following options:

  1. Broadcast

  2. Tele-Protection

  3. VCB

  4. VCB Branch Initiate

6 

In the Voice panel, configure the Companding Law and Signalling Type parameters. By default, the companding law is set to Mu-Law.

For information about which adapter cards support A-Law or Mu-Law, and which signalling types are configurable for each card, see the node documentation.

Note: Mu-Law encoding is used for North America, and provides up to 16 bridges per ISC, up to 24 branches per bridge, and up to 384 total branches per ISC. A-Law is used for the rest of the world. A-Law encoding provides up to 16 bridges per ISC, up to 32 branches per bridge, and up to 512 total branches per ISC.

7 

Click OK and confirm the changes.

8 

On the NE navigation tree, right-click on the Shelf and choose Properties. The Shelf (Edit) form opens.

9 

Click on the SCADA tab.

10 

Select one or more VCBs and set the Bridge Admin Status parameter to Up.

11 

Click Turn Up.

12 

Click on Properties. The SCADA Bridge - VCB form opens.

13 

If you are configuring a VCB branch initiate, configure the VCB Idle Code and VCB Seized Code parameters as required.

14 

Click on the Branches tab and click Create to create a SCADA branch. The SCADA Branch (Create) form opens

15 

On the General tab of the SCADA branch, set the Administrative State parameter to Up, and configure the Description, Gain Input (dB) and Gain Output (dB) parameters.

16 

Click OK and confirm the changes.

17 

Configure more SCADA VCB branches as required. You can add SCADA VCB branches as SAPs on an L2 access interface on a VLL Epipe or Cpipe service site. See To create a VLL L2 access interface on a terminating site for more information.

End of steps