Subject: [IPTEL] RTP measuring

From: S_S_Dinesh/India/[email-masked]
Date: Mon, 8 May 2000 14:10:16 +0530

Hello all,

I have three questions related to RTP/RTCP.
1. Are there any  tools for monitoring RTP/RTCP (free or commercial)? I am
interested especially in RTP analysis, and not RTCP parsing. And, if there
are, which are their capabilities?
In order to restrict the range of replies, I must mention that I've already
found:
- Hammer VoIP Test System - analysing all the parameters (drop packets,
jitter, delay) within a VoIP call
- HP Internet Advisor - similar
(for these two commercial packages, I couldn't get more information about
what actually is monitored)
- rtpmon, which is free, but, in spite of its name, it is an RTCP
monitor.

2. Can anybody explain me what is the structure of a compound RTCP packet?
I know, from the RTP specification, that it looks like this:

if encrypted: random 32-bit integer
|
|[------- packet -------][----------- packet -----------][-packet-]
|
| receiver reports chunk chunk
V item item item item
--------------------------------------------------------------------
|R[SR|# sender #site#site][SDES|# CNAME PHONE |#CNAME LOC][BYE##why]
|R[  |# report #  1 #  2 ][    |#             |#         ][   ##   ]
|R[  |#        #    #    ][    |#             |#         ][   ##   ]
|R[  |#        #    #    ][    |#             |#         ][   ##   ]
--------------------------------------------------------------------
|<------------------ UDP packet (compound packet) --------------->|
#: SSRC/CSRC

The question is, as I couldn't understand the figure: how is the above
figure packetised in UDP packets (is it 'line-by-line') ?

3. Are there any standards for encrypting RTP/RTCP (in relation with H.323)
? Besides inserting the 32-bit integer in the RTCP packet and using DES
there is nothing else specified.

Thank you very much
Best regards
Bogdan Ghita