IP
Video Conferencing
David Marshall
IST 250
Network Management
October 22, 2003

Back To Slide Show

Introduction
Bandwidth
QOS (Quality Of Service)
Security
Scalability
Conclusion
Works Cited

Introduction
In recent history there has been a dramatic increase in the amount of available resources of computer networks, that is the capacity of computer networks, as well as an increase in the utilization of that capacity. Web traffic, voice and video over IP, and other multimedia applications have significantly contributed to the increase in traffic on our networks. Many applications, such as the interactive multimedia applications, not only require large amounts of bandwidth, but also require specialized service from the network. The network must accommodate such traffic without excessively degrading the quality of service of other applications in the network, some of which may be mission critical. IP videoconferencing is one type of application that requires special service from the network. To provide predictable performance, videoconferencing requires significant bandwidth with minimal delay, jitter and loss. The failure to provide the required network quality has been one of the major obstacles hindering the popularity and exploration of this application. The growth of the Internet and IP networks, together with the universal adoption of standards for multimedia conferencing over packet networks, and the high cost of travel have caused businesses to switch to videoconferencing over IP networks. The reduced cost of videoconferencing equipment, affordable desktop stations, cheaper bandwidth, continually improving video quality and the availability of enhanced video-related services are driving businesses to adopt Vidio Conferencing as a cost-effective means for internal and external communications. In this paper I will discuss several factors that must be considered for the successful implementation of video conferencing in an IP network environment which include bandwidth, quality of service, security, and scalability.
Back to Top




Bandwidth
One major factor for successful IP Conferencing is ensuring that there is enough bandwidth to maintain acceptable levels of voice, video, and data transmission. Both traditional data network bandwidth considerations and usage issues need to be taken into account when determining the required amount of bandwidth. For example: Optimization -- the use of features such as silence suppression can result in a bandwidth saving of at least 50%. Overhead -- such as Packet Overhead, where each packet that an IP network transmits has a header that requires approximately 40 bytes. Usage Modeling -- calculating the Erlang factor (the ratio of the number of conference terminals in the network to the number of conference terminals actually in use at any given time) and Busy Hour Calls (at certain times of the day more people will be in a conference than at other times of the day).
Back to Top




QOS (Quality Of Service)
Another issue of IP videoconferencing is to offer a quality audio and video experience to the end user. One of the challenges to achieving this goal is getting acceptable service from the network. The best tool that is available to meet this challenge is QoS. Currently, the H.323 gatekeeper is the one-videoconferencing component for providing some QoS in the case of H.323-based videoconferencing. In addition, three major initiatives are attempting to solve QoS issues (RSVP and DiffServ from the IETF, and 802.1p from IEEE). However, the work is not complete and the necessary bandwidth is not yet universally available, so it will be some time before QoS is fully resolved within and between enterprises.
Back to Top




Security
Because of multiple security risks from viruses, and hackers, some network managers are not willing to compromise the integrity of their organizations networks. It is a massive undertaking for IT managers to simply protect and secure the network and the data being transmitted across it. There is a reasonable unwillingness to install IP-based audio and video applications. Opening multiple TCP and dynamically changing UDP ports on the firewall is not a viable option to complete a single audio or video session across the Internet. Doing so could compromise the security of the enterprise.
Back to Top




Scalability
IP networks are essentially different from ISDN networks. IP networks have a distributed and flexible architecture that spans LAN, WAN and/or the Internet. The IP infrastructure is location and service-provider independent. The inherent scalability of IP allows bandwidth to be increased, equipment to be added and services to be improved without making any fundamental changes to the underlying infrastructure. One of the main advantages of IP videoconferencing is that the communication system goes where the IP network goes. This allows companies to scale from internal conferencing over the LAN to multi-location, global conferencing over a WAN. The equipment is software driven and the network results in a fully scalable, location-independent, cost-effective communication system. By definition, videoconferencing incorporates audio conferencing. Most organizations have already adopted voice conferencing as part of their corporate culture. As videoconferencing becomes more mainstream, because the IP infrastructure allows for a seamless transition from voice to video, more and more organizations will be able to expand from voice to enhanced videoconferencing services.
Back to Top




Conclusion
Using packet-based networks for real-time communications is increasing interest in merging voice, video and data communications. With continual, increasing and affordable bandwidth, IP provides an excellent means of cost-effective videoconferencing. As IP videoconferencing solutions are implemented, careful choices must be made to guarantee that the necessary infrastructure is in place to support it. Network and conferencing issues like bandwidth, quality of service, security, and scalability must be successfully addressed.
Back to Top




Works Cited
  • http://www.DeployingSecureIPVideoNetworks.pdf
  • http://www.QoSforIPVideoconferencing.pdf
  • http://www.wvn.ac.uk/presentations/LIVEIPVCMFY.pdf
  • http://www.h323forum.org/papers/IPCentric.pdf
  • http://developer.intel.com/technology/itj/q21998/articles/art_4.htm

  • Back to Top