Handle slightly outdated UNF gracefully

mxsasha commented 3 months ago

Scenario:

Server publishes new UNF version 22 with new delta, all valid.
Server pushes this to CDN.
Client updates to this version.
CDN has slow synchronisation, so not all nodes have latest update yet - some still have the v21 UNF.
Client updates again, hits different node, gets version 21 UNF.

I think the current implementation in IRRD consistent with the current text says: UNF invalid, reset session. I think this should have more grace. Particularly with #33 allowing us to detect real history rewrites.

Suggestion: when clients find an otherwise valid UNF with one version lower than the current client version, it should do nothing. No changes, no updates, just ignore and check again in a minute. More than one version behind -> reset.

Credit to Tim Bruijnzeels for raising this at RIPE88.

job commented 3 months ago

This is the way

stkonst commented 3 months ago

I do agree that if a client detects a UNF with lower version, then he should simply ignore it.

Shall we update section 5.2 with this recommendation?

Also, shall we include a recommendation that if client detects a session_id mismatch then it must immediately reset ?

mxsasha commented 3 months ago

Made #37 for this. We did already cover this more than I thought, it is a reject, not a reset, if the UNF matches. Still, added a recommendation on the difference between small offset and large offset.

Also, shall we include a recommendation that if client detects a session_id mismatch then it must immediately reset ?

That's already in there.

mxsasha / nrtmv4

Handle slightly outdated UNF gracefully #36