Using ConferenceXP in a Multicast Network
Contents
About multicast
Choosing a multicast IP Address
Troubleshooting multicast
For best performance, run ConferenceXP in a network that is reliable, offers decent performance, and permits multicast connections within or between organizations.
About multicast
ConferenceXP is a peer-to-peer application, which means it sends data between ConferenceXP clients, instead of sending data to or receiving data from a server. To support simultaneous users while keeping network traffic to a minimum, ConferenceXP uses multicast to send data. By using multicast, a ConferenceXP client can send data once to all ConferenceXP clients set up to receive the data.
Unicast streams data as point-to-point connections, all of which use valuable network resources. Multicast streams data as one broadcast, thereby using less network resources than unicast streams.
Multicast is often disabled across the Internet or across many corporate wide area networks (WANs) because of incompatibilities between different routers, because it has been used for denial of service attacks, or because of performance problems caused by applications that send a lot of data. When multicast is disabled across network boundaries, sending a multicast signal will fail because the multicast traffic is stopped, or filtered, at the router.
To prevent a failed multicast signal, use ConferenceXP over a local area network (LAN), such as one within a building, or over Internet2. On a local area network where there are either no routers, or where the routers have been configured to bridge (that is, pass unchanged) multicast packets, ConferenceXP will work properly. If a wide area network has been designed to work with multicast from end to end, then ConferenceXP will work there as well. Currently, Internet2 is one of the few wide area networks that supports multicast.
ConferenceXP is designed for high speed networks, that is, 2 megabits per second (Mbps) or faster, which enables multipoint and high-quality conferencing. For slower networks, such as 128 Kilobits per second (Kbps) xDSL and cable modems or 56 Kbps analog modems, other products such as MSN® Messenger are a better fit because they have been optimized for these speeds.
The lowest recommended network speed for ConferenceXP is 500 Kbps of sustained throughput with low packet loss (< 5%). However, ConferenceXP typically uses 2–3 Mbps of sustained throughput. For best performance, the recommended network speed is 5-10 Mbps of total throughput between all ConferenceXP clients, since there will be more traffic over the network than just ConferenceXP.
Top 
Choosing a multicast IP address
The range of Multicast IP addresses is 224.0.0.0 to 239.255.255.255. Some addresses, as specified in the table below, are reserved for specific purposes. When specifying a multicast IP address for a ConferenceXP venue, you’ll need to make sure the address you specify is not a reserved, well-known address. If the venue is for an internal-only network, select a multicast IP address in the limited scoped range. If the venue is for a network that supports external addresses, select a multicast IP address in the globally scoped range.
Multicast IP Address Range |
Description |
224.0.0.0 – 224.0.0.255 |
Reserved for "well-known" multicast IP addresses |
224.0.1.0 – 238.255.255.255 |
Globally scoped addresses (that is, Internet or external) multicast IP addresses |
239.0.0.0 – 239.255.255.255 |
Limited scoped (that is, internal or local) multicast IP addresses |
For more information about using IPv6 addresses, see About Using IPv6 Addresses in ConferenceXP.
For more information about multicast addresses, see these resources:
Top
Troubleshooting multicast
If Multicast isn’t working at your site, try the following:
Top
|
|
