Erik Kline Ballot Comments

[SpencerDawkins]

From @ekline:

S3.4

• It seems like the final paragraph is attempting to describe a real-world experience. It would be great if there were a citation for this (but understandable if nothing had been made public).

S3.6

• RFC 5594 does not appear to contain the word "throttle". It might not be great to inject this term here? 5594 instead seems to use phrases describing approaches to "congestion management".

S4.4

• Seems like the introduction of the term "manifest" without any definition, explanation, or reference. Is there some explanatory text or reference that might be included?

[SpencerDawkins]

@acbegen and @GrumpyOldTroll - I'm not sure who wrote this text, except I don't think it was me.

And as with other parts of the ecosystem, new technology brings new challenges. For example, with the emergence of ultra-low-latency streaming, responses have to start streaming to the end user while still being transmitted to the cache, and while the cache does not yet know the size of the object. Some of the popular caching systems were designed around cache footprint and had deeply ingrained assumptions about knowing the size of objects that are being stored, so the change in design requirements in long-established systems caused some errors in production. Incidents occurred where a transmission error in the connection from the upstream source to the cache could result in the cache holding a truncated segment and transmitting it to the end user's device. In this case, players rendering the stream often had the video freeze until the player was reset. In some cases the truncated object was even cached that way and served later to other players as well, causing continued stalls at the same spot in the video for all players playing the segment delivered from that cache node.

@ekline was curious if there's a reasonable reference that we could provide for this.

S3.4 It seems like the final paragraph is attempting to describe a real-world experience. It would be great if there were a citation for this (but understandable if nothing had been made public).

[GrumpyOldTroll]

Yeah, that was me. There was not a public reference for this, alas, just a word of mouth anecdote.

[SpencerDawkins]

@ekline - I agree with you about your comment on Section 3.6. It happens that I got comments that Section 3.6 and 3.7 didn't need to be nearly as detailed as they were, so they were heavily rewritten. The text where "throttled" was used is now in Section 3.6.1, and the emphasis is now on the cause of unexpected traffic profile changes, rather than the ISP response to the unexpected traffic profile changes in this specific incident, so the text that included "throttled" has been removed.

[SpencerDawkins]

@ekline - I agree with your comment on Section 4.4, that some description or reference should be provided for the word "manifest".

The next occurrence of "manifest" is in Section 5.2, which does provide a description.

Media servers can provide media streams at various bitrates because the media has been encoded at various bitrates. This is a so-called "ladder" of bitrates, that can be offered to media players as part of the manifest that describes the media being requested by the media player, so that the media player can select among the available bitrate choices.

I don't think that's quite right - I'd say

Media servers can provide media streams at various bitrates because the media has been encoded at various bitrates. This is a so-called "ladder" of bitrates, that can be offered to media players as part of the manifest that describes the media available from the media server, so that the media player can select among the available bitrate choices.

So I'm changing this definition, and moving it to the first occurrence of "manifest" in Section 4.4.

Thanks for helping us fix problems you didn't even tell us about. :upside_down_face: