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Frequently Asked
Questions
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Networking
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- What should I ask for when ordering ISDN-6 for videoconferencing?
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- When a telecoms company installs ISDN at a customer's premises, there are various configuration details that can be set. Some of these can affect the quality and reliability of the ISDN line, and hence the quality and availability of videoconferencing from that location.
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- These are the things that the WVN recommends that sites ask for when ordering and installing ISDN-6:
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- ISDN-6 is, in fact, three ISDN-2 lines.
- Ask for three distinct line numbers - one for each ISDN-2 line.
- Stipulate that the lines are for bonded use - for videoconferencing.
- I have ISDN-6 and all three numbers are the
same, what ISDN settings should I have?
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- Where the three numbers are the same, for outgoing calls the lines should be configured as
Point to Multipoint (for voice and data).
Also, if all three numbers are the same, for incoming calls the 'hunting group' should be set to
Sequential Pickup (the lines will be answered in order).
If these conditions are not met, it is highly unlikely that ISDN connections will be
correct and reliable.
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- Who should I contact if I suspect an ISDN
problem?
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- You may discuss the problem with the WVN Support Team (01792 295700), to confirm the nature of the fault or problem, but you will need to contact the supplier of the ISDN-6 lines if you suspect that they are faulty. For BT customers, ring 0800 154022 to report a suspected faulty line. For other telecoms companies, please consult your customer documentation.
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- How much do ISDN-6 calls cost?
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- Like
'normal' telephone calls, the cost of ISDN calls comprises partly of
the fixed-cost line rental, and partly the price-per-minute for each
call that is made. The actual charges will depend on the supplier of
telecoms services. ISDN calls are normally charged per channel. The
cost of each channel is normally equivalent to one telephone line. For
ISDN-6 calls the charges are therefore six times the cost of a
'normal' telephone call. Precise charges will vary between
institutions according to the service provider, the ISDN product, and
the local rental/pricing agreement. A very rough 'ballpark' figure
would be £30:00/hour for daytime use. A grant has been provided to
every F.E. institution in the WVN which covers the cost of
conferencing calls made for the first two years of the project.
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- Are
there any ISDN test numbers I can call?
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- The
WVN Support Centre has a test studio available at 01970 639469. use
your touchscreen in the usual way to call this studio. If there is
no-one in the office you will see a poster (or empty office!).
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- The Video
Technology Advisory Service (VTAS) offers a test card number which
will enable you to see if you can connect over ISDN. The number is:
0191 261 1225.
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- The functioning of the
equipment can also be tested with a loopback call by dialling 0000000.
Please have your mute button ready! ( your own audio and video are
encoded and then decoded and played back).
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- Can
I connect at less bandwidth than ISDN-6 (384kbit/sec)?
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- It
is possible to connect at ISDN-2 (128kbit/sec) or ISDN-4
(256kbit/sec). Calls will be of noticeably poorer quality, so we do
not advise this. However it may be necessary if the other end is a
non-WVN location and has only ISDN-2 or ISDN-4 available.
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- Can
people connect to the WVN videoconferencing studios from home, or from
a business location?
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- If the location has suitable equipment that adheres to the H.320 standard, and has at least an ISDN-2 connection, they should be able to connect to a WVN studio, and even a multipoint conference using the JVCS. If they have an Internet connection and a multimedia PC with webcam and videoconferencing hardare and software that adheres to the H.323 standard then they should also be able to connect over the Internet.
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- In either case the quality will not be as good it is between WVN studios, and will depend on the the quality of the equipment, the videoconferencing software, the network connection, etc. The quality is likely to be very poor if the connection is via the Internet using a modem, but may be useable, depending on the context and purpose of the communication.
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- The WVN Support team can not offer support for this type of
use, but will advise if time permits.
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- What network equipment will be provided?
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- The Welsh Video Network will provide a Switch and Gatekeeper/Proxy server for each institution. The WVN Switch is a 12/24 port box. The WVN Gatekeeper/Proxy will have two Fast Ethernet interfaces only one of which will be used in the first instance - connected to the WVN Switch.
The institution's main site router will be upgraded as part of the MAN
re-procurement.
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- What does the Gatekeeper/Proxy server do?
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- Your local Gatekeeper will set up H.323 calls with remote sites by contacting the remote Gatekeepers. The local and remote gatekeepers each know about their own CODECs in their local WVN Studios. The Proxies provide security for the WVN Studios by masking the IP addresses of the CODECs from the outside world.
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- What maintenance cover applies to the WVN
networking equipment?
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- The WVN equipment which is installed at institutions will be covered by a 2 year maintenance contract from the date of delivery. This includes advance replacement of faulty equipment within 48 hours (2 working days). All faults must be reported to the WVN Support Centre.
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- Who will configure and support
the WVN equipment?
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- All of the WVN equipment will be remotely configured and managed by the WVN Support Centre. The status of the equipment will be monitored 24 hours a day, 365 days a year. Full IP access will be required by the WVN Support Centre to all WVN equipment: the CODEC, Gatekeeper/Proxy and Switch, through the MAN access router. The WVN equipment must therefore be left switched on at all times. Institutions are not expected to configure and manage the WVN equipment.
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- What network connections are required in the WVN Studios?
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- Three UTP/RJ45 100Mb full duplex connections are required in the WVN Studios:
- For the CODEC, connected to the WVN Switch. (If the distance from the Studio to the WVN Switch is greater than
100m, or the Studio is at a different campus from the WVN Switch,
you may want to use a dedicated fibre connection or connect the CODEC
to the Switch via the LAN.)
- For the Data and Application Sharing PC, connected to the LAN.
- For occasional laptops, connected to the LAN.
- These connections should have been installed by the institution as part of studio refurbishment.
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- What other network connections are necessary?
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- Apart from the CODEC connection, three UTP/RJ45 100Mb full duplex connections to the WVN Switch are required:
- To your institution's MAN Router. Videoconferencing traffic only will pass through the WVN Switch. The MAN Router must be able to provide
Quality of Service for videoconferencing traffic. The Welsh MANs have funds allocated from the Welsh Video Network budget specifically to provide this level of functionality. Until the new MAN Routers are in place, the WVN Switch will be connected to a convenient campus network point. The connection can then be moved over to the Router once the MAN upgrades are completed. An additional IP subnet will need to be temporarily configured on the existing Router interface facing the WVN Switch. Further details are available in the
Networking pages.
- To the WVN Gatekeeper/Proxy.
- To your campus backbone. This will allow studios not directly connected to the WVN switch to access the Gatekeeper/Proxy.
- These connections will be provided by the Welsh Video Network.
A discussion of suitable campus topologies is
available.
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- What are the security implications for the MAN-WVN-LAN links?
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- The Proxy acts only as an H.323 video traffic proxy server. All other IP traffic is blocked.
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- Is an IP Videoconferencing
Service available?
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- IP Videoconferencing is being rolled out across
the Welsh Video Network. If a studio is IP enabled, it will have
JVCS-IP as an option in the studio entry on the JVCS Booking
Service. The JANET IP Videoconferencing Service was formally
launched on February 17th 2003. Full details of the Service,
including technical details and guides, can be found here.
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- Is there any more information
available about the WVN IP videoconferencing service?
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- There are WVN pages on Internet (H.323)
videoconferencing at:
- http://www.wvn.ac.uk/support/ip.htm
There is further information about the development
of IP Videoconferencing by the Welsh Video Network at: http://www.wvn.ac.uk/ipvcp/index.htm
- Now the IP service is in place,
is it worth keeping ISDN?
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Most
colleges have chosen to keep their ISDN lines as originally installed. We recommend that each studio has at least ISDN2 installed as
a backup to IP. Obviously ISDN6 (the default for most studios) is of
much better quality than ISDN2, but costs more to keep in place. The
number of ISDN lines left as a backup should be determined by the
college, taking into account the reliability of the college's IP
link, the number of point to point ISDN calls made, the quality of
the backup service required and the finances available.
It is also
worth noting that an IP studio can conference with an ISDN-only studio via a
bridge, but call costs are incurred by the ISDN site. In some cases
colleges videoconference with sites who are unwilling to incur call
charges. In these cases some colleges prefer to keep all 6 ISDN
lines in order to dial out to these sites at a good quality.
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