inband-oam / ietf

IETF drafts
7 stars 15 forks source link

Incremental Trace, RemainingLen, unclear behavior #228

Open IurmanJ opened 3 years ago

IurmanJ commented 3 years ago

In section 5.4.1 "Pre-allocated and Incremental Trace Option-Types" of draft-ietf-ippm-ioam-data, I think it's pretty unclear what to do with RemainingLen when dealing with incremental traces. For instance, should the encap node set this (useless?) field to 0 (seems the most logical idea that comes in mind)? Should transit nodes ignore this field? Same reasoning for flags (aka the Overflow bit), which also seems useless with incremental traces, right?

But... previously, it is said the following:

"Incremental Trace-Option: [...] They then decrease the remaining length available to subsequent nodes and adjust the lengths [...]"

Which lets one thinking there is also a limitation on the trace size even with incremental traces, and so the RemainingLen field works exactly the same as for the pre-allocated mode.

Maybe should we clarify this part? Could be confusing...