Re: [babel] Mirja Kühlewind's Discuss on draft-ietf-babel-hmac-08: (with DISCUSS and COMMENT)

[Juliusz Chroboczek <[e-mail]>]

>>> You can also use a different timer e.g. 300s which would also ensure
>>> that a challenge is not send more often than 300s (expect in the case
>>> where you got a challenge reply but in case you are not talking to an
>>> attacker and usually not need to send another challenge request
>>> immediately).

>> If the challenge reply is lost, then the challenge needs to be resent.  It
>> would not be acceptable to cause a 5 min blackhole after a single packet
>> loss.

> Why 5 mins?

You're suggesting 300s in the excerpt cited above.

> If the challenge needs to be retransmitted, then the mechanism for
> retransmitting seems to be missing in the draft or what do I miss?

A -> B: Challenge
B -> A: Challenge reply gets lost

B -> multicast group: normal control packet

(At B, the control packet fails the index test (5th bullet point in 4.3).)

A -> B: Challenge

-- Juliusz