[IPFIX] comments on draft-scholz-ipfix-rtp-msg-00

[Hadriel Kaplan <[e-mail]>]

Howdy,
I read draft-scholz-ipfix-rtp-msg-00 and have some initial comments, mostly at a high level for now instead of per-IE.

1) From a IPFIX IANA allocation perspective, it makes sense to get IANA-assigned IE numbers for things that could be exported from different vendors, instead of using PENs.  Quite a few of the IEs in this draft are fairly vendor-specific, however.  I mean in the sense that few media-monitoring vendors report the same type of information as in this draft.  I think there is some commonality across vendors, but it's a smaller list.  How do you want to handle that?  Do we get in a room and agree on a common list?

2) Some of the IEs in here imply the IPFIX records could be generated per-RTP packet.  I don't think you want to do that.  Some media-monitoring systems handle multiple millions of RTP packets per second. 

3) Some of the IEs imply there's a single SSRC for a flow - are you assuming a flow is by definition the 6-tuple of IP src/dest, port src/dest, transport type, and SSRC?  In other words, if there are two or more SSRCs in the same 5-tuple, would they be separate IPFIX flows? (they're only one "RTP" session from an RTP and SDP perspective)

-hadriel