Becta | Video conferencing - issues to consider
Video conferencing – issues to consider
Please note: This document has been archived and is for your information only. This document was originally published as an overview for the type of issues faced when schools were considering Video conferencing.
This advice has since been replaced by Becta’s Functional Specification, which is available here. The Functional Specification is also complemented by a Technical Specification which can be found in the same location.
Contents:
Introduction
Uses of video conferencing in an educational context
Common features of video conferencing systems
Issues to consider when purchasing video conferencing equipment
Types of video conferencing technology
Set-top systems
Roll-about systems
Room based systems
Environment
Running costs
Key standards
Introduction
Video conferencing enables direct face-to-face communication across networks. The term 'video conferencing' covers a range of communication activities and technologies. At one end of the scale are web-conferencing tools such as Yahoo Instant Messenger, which can be used with low-cost webcams on stand-alone PCs to provide basic video conferencing facilities. At the high end of the scale are dedicated video conferencing studios with specialist cameras, lighting and audio equipment. What each video conferencing system has in common is that two or more parties in different locations have the ability to communicate using a combination of video, audio and data. A video conference can be person to person (referred to as 'point-to-point') or can involve more than two people, when the term is 'multipoint'.
Becta is working with the DfES and UKERNA (the United Kingdom Education and Research Networking Association) to develop a national schools’ network. This will be a secure network, available from anywhere, allowing easy access to a wide range of high quality online applications, including video conferencing. Further information and advice on the development of video conferencing services for education can be found at:
http://getconnected.ngfl.gov.uk/docs/videoconferencing.doc
Uses of video conferencing in an educational context
Video conferencing has many benefits, as a tool for both teaching and learning. A key factor is that it provides real-time, visual communication, unlike other communications methods such as email. In an educational setting, video conferencing can provide:
· cross-institutional links
· value-added curriculum teaching, for example teaching languages to groups at other schools
· value-added services such as professional development for staff, for example allowing staff to work collaboratively with staff from other schools to share teaching methods and curriculum materials
· accessibility services, for example having a person signing a live lesson displayed “picture in picture”.
Many schools already use video conferencing to complement traditional teaching methods in various situations. In some cases, video conferencing is helping to cut costs, for example by having one teacher deliver a lesson to many classes at once. Another advantage is that video conferencing allows learners to interact with other learners with whom they would otherwise not have contact.
Video conferencing can also be used to conduct virtual visits that transport learners into new environments. There are many opportunities for video conferencing – whether for delivering material to a geographically dispersed audience in a lecture, or to a learner in a one-to-one meeting with a careers adviser.
Some schools use video conferencing as a way of bridging cultural gaps with learners of a similar age, but whose backgrounds are different. Examples might be learners from an inner city speaking to children from a rural school or learners in the UK speaking to learners from another country.
Video conferencing systems can also support application sharing. Here applications can be opened and seen and used by both users, with changes made by one user being seen by the other. This enables collaborative work on documents, drawings or data.
There have been studies of the impact of video conferencing on teaching and learning. Becta has published a paper 'What the research says about video conferencing in teaching and learning', available at http://www.becta.org.uk/research/reports/docs/wtrs_vidconf.pdf.
According to this research, some of the key benefits of video conferencing are as follows:
· it allows interactive access to experts
· it enables collaboration by teachers and learners with peers
· it enriches the experience of distance education by reducing feelings of isolation and encouraging interaction
· it raises student motivation.
Devon LEA has published a guide to video conferencing in the classroom, which includes a number of case studies from primary and secondary schools. This can be downloaded from the Becta website at:
http://www.becta.org.uk/leas/leas.cfm?section=7_1&id=1137.
Common features of video conferencing systems
Video conferencing terminals are often referred to as ‘endpoints’. They may be used by an individual or shared by a group. The following six elements are common to all video conferencing endpoints.
Camera: the camera captures live images to send across the network. This might be a low-cost USB webcam, a camcorder connected to a video capture card or a dedicated camera built in to the endpoint.
Visual display: this displays the images of the people taking part in the video conference. Often, displays include a ‘picture in picture’ facility, where the image being sent appears in a smaller window overlaid on the received image, to allow users to see how they are appearing to others.
Audio system: video conferencing audio systems include both microphones to capture audio from the endpoint and loudspeakers to play back audio received from other endpoints across the network connection.
Compression: depending on connection bandwidths, web sites with a lot of graphics can take some time to load and emails with a picture attachment can take some time to send. With video, the problem is magnified, as video comprises a series of many still pictures. This makes video conferencing a very bandwidth-intensive application. Video conferencing systems therefore include technologies, often referred to as codecs, to compress and decompress video and audio data, allowing transmission across a network connection in near-real time. Uncompressed video and audio data would be too large to be sent across all but the highest bandwidth network connections in anything approaching real time.
User interface and control system: this allows users to control interactions, such as placing calls, storing and locating numbers and adjust environment settings such as volume. The control system handles the underlying communication that takes place between endpoints. It is important that the user interface is as straightforward and easy to use as possible.
Network connection: the type of connection employed has a significant impact upon video conferencing. Generally, network connections used for video conferencing fall into two broad categories: ISDN (integrated services digital network) connections or IP (Internet protocol) connections. The key difference is that ISDN offers dedicated bandwidth for video conferencing, whereas IP networks do not.
ISDN: ISDN works on a circuit-switched basis, establishing a dedicated connection between the endpoints throughout the duration of the call. ISDN has been used in many legacy video conferencing systems and is still widely used today. ISDN lines can be grouped together to increase the available bandwidth, a pair of ISDN lines (or channels) provides a bandwidth of 128kbps when used together, sufficient for acceptable quality video conferencing. As ISDN-based video conferencing requires users to have compatible ISDN lines installed together with ISDN compatible video conferencing equipment, it is often employed to provide reliable video conferencing between fixed locations, such as between main and branch offices. ISDN costs include both a rental charge and ongoing call charges.
Many schools currently employ BT’s Schools Internet Caller (SIC) 128kbps ISDN service. This is a fixed-rate service intended for Internet access. Calls to the special 0820 number provided by the school’s internet service provider (ISP) via an SIC ISDN connection are free between the hours of 8am and 6pm Monday to Friday during term time, providing unmetered Internet access during these times. Calls to the ISP’s 0820 number outside these hours or to other numbers at any time will incur call charges. Hence if a school were to use its SIC ISDN connection to directly dial another school for video conferencing, this would incur call charges, as the call would be made to a number other than the 0820 number provided by the school’s chosen ISP. It would be theoretically possible to use the SIC ISDN connection to video conference using IP, but the bandwidth limitations and lack of quality of service (QoS, see below) would limit the practicality of this.
IP: in an IP-based network such as the Internet, sent and received data is divided into packets. Each packet may traverse a different path to reach its destination and packets may arrive in a different order from the order they were sent in. Another protocol, the Transmission Control Protocol (TCP), reassembles the packets in the right order. The unpredictable, packet-switched nature of the Internet can create reliability issues for IP-based video conferencing, even across broadband Internet connections. Hardware and software quality of service (QoS) mechanisms can be put in place to identify and prioritise certain types of network traffic, helping to prevent degradation of performance when congestion occurs and providing increased reliability for video conferencing applications.
IP-based videoconferencing does not incur additional call charges, in that it employs an institution’s existing Internet connection, rather than requiring an additional dedicated link. The increased availability of broadband networks in schools is beginning to make IP based conferencing more practical. The greater capacity of a broadband network and the fact that many (particularly the networks managed by Regional Broadband Consortia, or RBCs) are privately managed networks can offer more predictable performance, although other network traffic may still cause problems.
Because ISDN and IP networks use different protocols a bridge between the two is required to video conference between them. This bridge typically forms part of a regional or national network. For example, in the UK higher education sector, the Joint Academic Network (JANET) Video Conferencing Service (JVCS) provides gateway support for multipoint videoconferences that use both IP and ISDN. Some companies provide bridging as a chargeable service. A limited number of video conferencing units can bridge between ISDN and IP networks.
Issues to consider when purchasing video conferencing equipment
When preparing a functional specification for video conferencing equipment and services it is important to address equipment and location issues, connectivity and bandwidth issues and support and training issues.
Equipment and location issues:
· what level of quality does the equipment offer for video and audio?
· what features does the equipment offer (for example, camera tracking and zoom facilities)?
· how many participants do you envisage needing to use the system at once?
· where will the equipment be used – in a single, dedicated location or at a range of locations throughout the school?
· are there any existing AV resources in the school (for example, projectors, VCRs, camcorders, TVs, plasma screens, whiteboards) that you would like to incorporate into video conferencing facilities? Does the equipment offer sufficient connectivity for this?
· are there any aspects of your schools’ current network configuration and security (such as a firewall) that could impact on video conferencing? Firewalls may block incoming video conferencing traffic, and other traffic within the school’s network may cause bottlenecks.
· can the equipment or connectivity be upgraded over time to provide increased bandwidth or additional features?
· are any maintenance and support services or contracts available to you in relation to the equipment?
Connectivity and bandwidth issues:
· what connectivity and bandwidths are available – ISDN, broadband?
· what budget do you have for ongoing connectivity costs? Video conferencing over ISDN will incur both line rental and call charges; IP video conferencing does not incur these but requires broadband connectivity, which can be expensive.
· is it possible to employ any quality of service (QoS) to help ensure good performance of video conferencing over IP?
· do any special arrangements need to be made with your Internet service provider (ISP) in relation to IP video conferencing?
· what provisions are in place for video conferencing at a local and regional level? Does your LEA or Regional Broadband Consortium (RBC) offer any services or have any provisions or requirements for video conferencing in place that you should be aware of prior to purchasing equipment? Do they maintain any directory services of institutions you may be able to video conference with?
· who do you envisage video conferencing with – a fixed number of other schools and/or institutions, or are you looking to hold video conferences on a more “ad hoc” basis?
· are there any compatibility issues with the equipment and facilities of the institutions you intend to video conference with you should be aware of prior to making a purchase?
· do you envisage video conferencing with more than one other institution simultaneously (multipoint, as opposed to point-to-point)?
Support and training issues:
· how easy is the equipment to install and use? How straightforward is the user interface?
· what training for support staff and end-users will be required? Who will provide this?
· are any support and maintenance contracts and services available in relation to the equipment?
Further information and advice (including factsheets, user guides, studies and reports) on purchasing video conferencing equipment and services is available through the Video Technology Advisory Service (VTAS), a UKERNA service:
http://www.video.ja.net
Types of video conferencing technology
It is possible to set up a video conference with systems ranging in price from about £50 (in addition to the cost of a suitable computer) to over £15,000. The choice of system will depend on how you are going to use it, your budget and the level of technical expertise available.
There are four main categories of video conferencing system – desktop, set-top, roll-about and room-based systems – although, as technology advances, the distinctions between the systems are becoming less well defined.
Desktop systems
Hardware and software is available to turn desktop computers into a video conferencing endpoint. For PCs a PCI (peripheral component interconnect) card can be installed alongside other cards such as the soundcard to handle the compression and decompression of sent and received audio and video. USB devices are also available such as Polycom’s ViaVideo video communications appliance. Such devices should not be confused with USB webcams; unlike webcams, these devices perform the audio and video processing activities video conferencing requires, offloading the majority of these activities from the processor of the PC they are attached to. Software based systems are also available. Here compression/decompression functions are performed by the PC, placing a considerable strain on the processor. Generally, desktop systems retail for less than £1000. This should be considered as an additional cost to the cost of the PC they will be used with.