Network based Videoconferencing Steve Williams

Why don’t people use ILT / ICT Not relevant Not easy to use Not integrated Not reliable Not effective

£5.5million project with £2.1m European funding European open procurement Rollout and procurement group membership –Technical –Non technical –HE and FE representatives Focus on –Ease of use –Suitability for use in a teaching environment –Appropriate use of effective technology

3 x 29” monitors, 2 x cameras + document camera High quality audio and video Interactive whiteboard / Large video screen Dedicated ‘data PC’ for application sharing –We do not use data sharing facilities in VC equipment Laptop connection Up to 4Mbps connection speed

The Beginning… You have diverse groups of users on diverse network connected machines wanting to do different things at different times and they all want the network to respond in an appropriate manner. If you do not have an adequately ‘overprovisioned’ network… …the network must be able to differentiate between real-time critical and non-real time services.

Real-Time critical traffic Video Conferencing IP Telephony Video Streaming Web browsing MLE/VLE

Network Applications WWW MLE/VLE Videoconferencing IP Telephony Streamed Video WWW MLE/VLE Videoconferencing IP Telephony Streamed Video

Network Access School Access Router Internet Switch School RBC/ISP

An overprovisioned network is one where the traffic is able to flow freely from any point on the network to any other point without suffering from delays by being queued. If your network has bottlenecks or ‘low’ speed links and you want to run videoconferencing you must consider providing some guarantee of service to certain types of traffic… …or it will not be reliable.

Differentiated Services Ability to provide Quality of Service based on classes or types of traffic Expedited forwarding (EF-PHB) Real-time critical traffic Low-loss, low jitter, fastest throughput up to limit E.g. 1Mbps continuous throughput Videoconferencing and voice traffic Assured Forwarding (AF-PHB) ‘Guaranteed’ bandwidth over time x E.g. 1Mbps averaged over 10 seconds Video Streaming

Network Metrics for Videoconferencing Available bandwidth Enough! – actually enough x 1.5 minimum Availability Should never be < 99.95% (22 minutes/month) SLA should state measured per rolling month max Packet Loss <0.25% absolute max Inter Packet Delay Variation (IPDV or Jitter) +- 30ms Round Trip Time (RTT) or One Way Delay(OWD) <100ms (50ms)

Three normal classes + an option –EF (Voice and Video) –AF (Video Streaming and network updates) –BE (Best Effort – everything else) –LBE (Less than BE – throw away first) Providing Guaranteed Service EF – 20% of link AF - 15% of link BE - remainder

Think about The whole network path and the equipment in that path The type of traffic on each link The worst link in the chain Providing Quality of service Engineering connections

WVN Switch WVN Gatekeeper/proxy WVN Studio MAN Access Router 4 ports SWMAN / NWMAN MAN QoS WVN QoS H.323 only Campus QoS VLAN & queuing Campus core switch/router Remote Campus switch/router Firewall Institution Network Topology

WVN is hybrid ISDN & IP solution ISDN = circuit switched –Call setup, dedicated bandwidth Just like a telephone call IP = packet switched –Call setup, contended bandwith More like a very fast postal service

The Welsh Video Network