Should tracing be a separate spec from CMSD and if so, under which SDO?

[wilaw]

Some background on this issue. As we design various implementations of tracing, it becomes apparent that these have applicability across many application verticals of internet delivery (web sites, images, css, js, IOT, webRTC etc) aside from the media delivery vertical on which CMSD is focused. A CDN would not want to implement one tracing standard for media objects, another for images, a thirds for web scripts. A single tracing standard which supports use-cases across these verticals makes more sense and is more likely to receive a higher level of attention and implementation. There was some consensus in the 10-11-21 CMSD meeting that tracing should be a separate spec. The question was raised that if this is to be the case, which SDO should it be developed under. Two candidates were suggested - the CTA and IETF.

[zen-tek]

After some additional discussion within the SVA QoE working group we have reached the following consensus:

Tracing is a larger effort than CMSD. It likely requires modifications to CMCD and development of a new CDN logging specification/standard to ensure delivery of telemetry under high latency scenarios (i.e. response headers are not received due to HTTP timeouts). There is also certain data that cannot be determined at time of response header delivery but can be logged after the fact. It will also require recommendations or specifications for player-specific behaviors outside the scope of CMSD.

Also, while streaming video has unique challenges, it is only one of several use cases for a more general content delivery tracing initiative. This initiative could broadly address behaviors from client through edge through middle tiers and origins, leaving room for other recommendations or specifications for video specific technologies like players, packaging, and encoding. An umbrella project within the SVA could coordinate the set of recommendations, specifications, and standards which support tracing for streaming video more holistically.

In terms of where the content delivery tracing initiative lives - CTA seems the right organization and, ideally, many of the same participants in the CTA CMSD effort would participate in the related content delivery tracing effort.

[piersoh]

In this context, and potentially CMSD, there is also the work of the W3C on trace-context - it seems that this work was partially connected with OpenTelemetry/CNCF - though their spec seems more oriented around things like tracing container performance etc. I'm not sure how much further W3C or CNCF is going with this.

[wilaw]

Group consensus - tracing is a larger project than CMSD and we will no longer seek to define it within this WG.

Options to continue the work:

• CTA are open to generating a new WG and spec - however may be resource constrained (time slots, staff and attendees) in short term.
• IETF HTTPAPI WG may have interest and is chartered. Can also create new WG.
• W3C (see Piers comment above).