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Introduction
During 2002 the WVN became an IP as well
as an ISDN network, built on the new North
Wales MAN and the South
Wales MAN.
This means that the network uses
both the public ISDN network, built on digital telephone lines
similarly to the public telephone network, as well as making
use of data connections to the JANET network and beyond to the
public Internet. The videoconferencing service is then
transmitted across data networks in the same fashion as emails
and web pages.
The main advantage is that IP calls are not
charged by a telecoms provider on an individual basis but are budgeted for as part of the general charges for
JANET/Internet access. In addition, IP calls utilise greater bandwidth than ISDN-6 allows, which
results in better video and audio quality.
Technical
description
All Internet services are
defined according to protocols which provide the rules for
communication between Internet connected hosts/computers. The
protocol suite that is the enabling technology for the WVN is
known as H.323. The JANET Videoconferencing Service - IP (JVCS -
IP) which was launched on February 17th 2003 also uses the
H.323 protocol suite. Documentation to support the JVCS - IP
service is available here.
The support
pages of this site have a brief introduction
to H.323, with an explanation of
terms. For those wishing to delve deeper, there is also a
series of H.323
Development Links.
The new MAN architecture will
provide a dedicated Fast Ethernet interface at each institution
for the Welsh Video Network. Each institution's studios and
gatekeeper will connect to this port via a
Cisco 3524 switch. The gatekeeper runs on a Cisco 3662.
Both the switch and gatekeeper are supplied, installed,
configured and maintained as part of the project.
Illustration of WVN and
Institutional connections
Central equipment for the
service is already in place and consists of two Cisco 3540
MCU's, each of which is capable of hosting 24 simultaneous
connections, along with associated gatekeepers.
Institution gatekeepers have
been installed and configured.
Follow the links on the right
for more information.
UK H.323
Architecture Group
The report of the H.323
Architecture group is now available. This report covers the
structure needed to run a UK national IP videoconferencing
service and looks at such issues as physical equipment location,
addressing, security and QoS requirements. The WVN IP pilot and
service will be developed in accordance with the recommendations
made in the H.323 Architecture Group's final report.
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