blank.gif (43 bytes)

Church Of The
Swimming Elephant

6.2.2 Allocation of source description bandwidth Connected: An Internet Encyclopedia
6.2.2 Allocation of source description bandwidth

Up: Connected: An Internet Encyclopedia
Up: Requests For Comments
Up: RFC 1889
Up: 6. RTP Control Protocol -- RTCP
Up: 6.2 RTCP Transmission Interval
Prev: 6.2.1 Maintaining the number of session members
Next: 6.3 Sender and Receiver Reports

6.2.2 Allocation of source description bandwidth

6.2.2 Allocation of source description bandwidth

This specification defines several source description (SDES) items in addition to the mandatory CNAME item, such as NAME (personal name) and EMAIL (email address). It also provides a means to define new application-specific RTCP packet types. Applications should exercise caution in allocating control bandwidth to this additional information because it will slow down the rate at which reception reports and CNAME are sent, thus impairing the performance of the protocol. It is recommended that no more than 20% of the RTCP bandwidth allocated to a single participant be used to carry the additional information. Furthermore, it is not intended that all SDES items should be included in every application. Those that are included should be assigned a fraction of the bandwidth according to their utility. Rather than estimate these fractions dynamically, it is recommended that the percentages be translated statically into report interval counts based on the typical length of an item.

For example, an application may be designed to send only CNAME, NAME and EMAIL and not any others. NAME might be given much higher priority than EMAIL because the NAME would be displayed continuously in the application's user interface, whereas EMAIL would be displayed only when requested. At every RTCP interval, an RR packet and an SDES packet with the CNAME item would be sent. For a small session operating at the minimum interval, that would be every 5 seconds on the average. Every third interval (15 seconds), one extra item would be included in the SDES packet. Seven out of eight times this would be the NAME item, and every eighth time (2 minutes) it would be the EMAIL item.

When multiple applications operate in concert using cross-application binding through a common CNAME for each participant, for example in a multimedia conference composed of an RTP session for each medium, the additional SDES information might be sent in only one RTP session. The other sessions would carry only the CNAME item.

Next: 6.3 Sender and Receiver Reports

Connected: An Internet Encyclopedia
6.2.2 Allocation of source description bandwidth


Protect yourself from cyberstalkers, identity thieves, and those who would snoop on you.
Stop spam from invading your inbox without losing the mail you want. We give you more control over your e-mail than any other service.
Block popups, ads, and malicious scripts while you surf the net through our anonymous proxies.
Participate in Usenet, host your web files, easily send anonymous messages, and more, much more.
All private, all encrypted, all secure, all in an easy to use service, and all for only $5.95 a month!

Service Details

Have you gone to church today?
All pages ©1999, 2000, 2001, 2002, 2003 Church of the Swimming Elephant unless otherwise stated
Church of the Swimming Elephant©1999, 2000, 2001, 2002, 2003 is a wholly owned subsidiary of Packetderm, LLC.

Packetderm, LLC
210 Park Ave #308
Worcester, MA 01609