rtsp协议相关之-rfc1889(RTP 实时应用传送协议文档).txt[32]

[入库:2006年2月23日] [更新:2007年3月24日]

本文简介:

   From the sender information, a third-party monitor can calculate the
   average payload data rate and the average packet rate over an
   interval without receiving the data. Taking the ratio of the two
   gives the average payload size. If it can be assumed that packet loss
   is independent of packet size, then the number of packets received by
   a particular receiver times the average payload size (or the
   corresponding packet size) gives the apparent throughput available to
   that receiver.

   In addition to the cumulative counts which allow long-term packet
   loss measurements using differences between reports, the fraction
   lost field provides a short-term measurement from a single report.
   This becomes more important as the size of a session scales up enough
   that reception state information might not be kept for all receivers
   or the interval between reports becomes long enough that only one
   report might have been received from a particular receiver.

   The interarrival jitter field provides a second short-term measure of
   network congestion. Packet loss tracks persistent congestion while
   the jitter measure tracks transient congestion. The jitter measure
   may indicate congestion before it leads to packet loss. Since the
   interarrival jitter field is only a snapshot of the jitter at the
   time of a report, it may be necessary to analyze a number of reports
   from one receiver over time or from multiple receivers, e.g., within
   a single network.


Schulzrinne, et al          Standards Track                    [Page 30]

RFC 1889                          RTP                       January 1996


6.4 SDES: Source description RTCP packet

 0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|V=2|P|    SC   |  PT=SDES=202  |             length            | header
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
|                          SSRC/CSRC_1                          | chunk
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   1
|                           SDES items                          |
|                              ...                              |
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
|                          SSRC/CSRC_2                          | chunk
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   2
|                           SDES items    &nbs

本文关键:rtsp协议相关之-rfc1889(RTP 实时应用传送协议文档).txt
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