Voice Bridging Guidelines

Last Updated: 1 May 00

PURPOSE:

The purpose of these guidelines is to provide the colleges of the Virginia Community College System with the information they need to implement and utilize voice bridging services.

SCOPE:

These guidelines cover the strategy and components used to deliver voice bridging services to the VCCS, using existing VoIP network services.

This document will be updated to adapt to changes in technology, as they occur.

APPLICABILITY:

These guidelines are applicable to all colleges and campuses within the VCCS.

GUIDELINES:

These guidelines provide a new VoIP network service, voice bridging. The colleges may use it to leverage their investment in VCCS VoIP network services by conducting telephone (voice only) conferences without having to rely on, and pay for, non-VCCS voice bridging services.

Strategy:

The voice bridging strategy is to use a shared voice bridge that is accessed via the existing VCCS VoIP network services to conduct telephone conferences. It provides voice bridging services to users of IP telephones, all on-net telephones within VCCS, and all off-net telephones on the PSTN via the VoIP gateway routers on each VCCS campus.

All of the on-net calls are “local” calls, with no associated long distance charge. The off-net calls may be “local” or “long distance” depending on the location of the caller when they place their call. Any long distance charges will be billed to the caller, not to the VCCS or the colleges.

Voice Bridging Components:

The voice bridging service includes the voice bridge, a VoIP gateway router at the bridge, a pseudo telephone number assigned to the bridge, a real college telephone number(s) that is (are) dedicated to accessing the bridge, and the existing VCCS VoIP network services.

Voice Bridge:

The voice bridge is capable of supporting 46 concurrent calls in up to 12 concurrent conferences. It is a shared network resource that is operated by the VCC Utility.

VoIP Gateway Router:

The voice bridge is connected to the VCCS VoIP network via a VoIP gateway router. It has two T1 interfaces, providing 46 voice channels to the bridge and an ATM OC-3 port to connect it to VCCS network.

Voice Bridge Pseudo Telephone Number:

The voice bridge is designed for use on the PSTN. As such, it can only be accessed via a “telephone number”. The VoIP network design supports such a configuration by allowing a “telephone number” to be assigned to the bridge and routing call setup requests to it over the VoIP network. This is not a real telephone number that can be dialed from the PSTN. It only provides a means of identifying the voice bridge within the VCCS VoIP network.

Voice Bridge Access Telephone Number:

There must also be a real telephone number that off-net customers can use to access the voice bridge. Each college will provide a real telephone number that is dedicated to accessing the voice bridge. This is exactly the same approach as the dedicated telephone number used by students to access the IVR unit.

The colleges with PBXs will program their PBXs to replace the real bridge access telephone number with the pseudo bridge telephone number in incoming call setup requests and forward the calls to the campus VoIP gateway router. The campus VoIP gateway router will route the call setup request to the VoIP gateway router at the bridge.

The colleges with Centrex service will have their telephone company insert the pseudo bridge telephone number in place of the real telephone number that was dialed and forward the call setup request to the campus VoIP gateway router. The campus VoIP gateway router will route the call setup request to the VoIP gateway router at the bridge.

VCCS VoIP Network Services:

VCCS VoIP network services consist of a VoIP gateway router on each college campus and a virtual IP WAN backbone. The campus VoIP gateway router is connected to either the campus PBX or the campus Centrex system, providing access for campus and PSTN telephones. It is also connected to the campus ATM switch to provide IP access to all of the other VCCS campus VoIP gateway routers.

Each campus VoIP gateway router is configured with the pseudo telephone number of the voice bridge and the IP address of the VoIP gateway router at the bridge. This allows each campus router to translate call setup requests for the bridge pseudo telephone number to the correct IP address.

Voice Bridging Operation:

Any authorized VCCS customer may call the VCC NOC to schedule a conference for a particular time and date. The caller will be given the bridge telephone number to call and the password for the conference. The person requesting the reservation will then inform all conference participants of the time, date, bridge telephone number, and the conference password.

On-Net Callers - The caller will dial the access code for his/her campus VoIP gateway router to access the VCCS VoIP network. They will then dial the pseudo telephone number assigned to the voice bridge. The bridge will then ask the caller for his/her password. The bridge will connect the caller to the conference that has the same password as that given by the caller.

Off-Net Callers - The caller will dial the real bridge access telephone number assigned by the college. The PBX or Centrex system will translate the real number to the bridge pseudo number. The call setup request will then be passed to the campus VoIP gateway router, which will pass the call to the VoIP gateway router at the bridge. The bridge will then ask the caller for his/her password. The bridge will connect the caller to the conference that has the same password as that given by the caller.

The bridge will terminate the conference at the scheduled time, or when all of the participants have disconnected.

Security:

All voice resources are to be protected, by their owners, in accordance with the Virginia Community College System security policy. See the “Distributed Security” model on the System Office Web server for more information.

The colleges are responsible for providing physical security and access authorization services for their VoIP gateway router.

Support:

The Utility and the colleges should maintain service contracts on all of their equipment, to facilitate repair and replacement of defective devices.

Technical support is organized into three levels:

Level 1, the college:

College support staff provides the point of contact for their customers. They are expected to resolve routine problems related to IP networking and telephone systems.

Level 2, the Utility Call Desk:

Call Desk staff provides the point of contact for college support staff and college customers. They are expected to resolve routine problems related to VoIP networking.

Utility product specialists will work with college support staff and vendors to research solutions to non-routine VoIP problems, and to obtain appropriate solutions such as product patches, new releases, etc.

Level 3, the vendors:

The vendors are responsible for maintaining their products by providing product patches, information, new releases, etc.