Jean-Michel,
I understand that Probe addresses two operational needs. One need is to probe
the local node and the other is to probe a directly connected node. But in
either case, Probe semantics must be consistent.
Probe queries the status of exactly one interface. Regardless of whether the
L-bit is set or clear, if two interface satisfy the Extended Echo Request Match
criteria, the Extended Echo Reply must return an error code (3). Returning any
information beyond that would be risky. For example, assume that both
interfaces are active, one is running IPv4 only and the other is running IPv6
only? What would the Extended Echo Reply return?
Ron
From: Jean-Michel Combes [mailto:[email protected]]
Sent: Monday, November 6, 2017 7:09 AM
To: Ron Bonica <[email protected]>
Cc: [email protected]
Subject: Re: [Int-area] Intdir early review of draft-ietf-intarea-probe-00
Hi Ron,
2017-10-31 17:45 GMT+01:00 Ron Bonica
<[email protected]<mailto:[email protected]>>:
Hi Jean-Michel,
The semantic of this utility is to probe exactly one interface at a time. If
multiple interfaces satisfy query’s match conditions, Probe can’t provide a
response.
I agree that Probe could set the A bit if all of the interfaces are active. But
what should it do if one interface is active and the other is not?
<JMC>
Your opinion differs from my opinion because, IMHO, yours is mainly based on
the "probed interface resides on the probed node" (i.e., it is possible to
identify some interfaces are active and some not) and mine is mainly based on
the "probed interface doesn't reside on the probed node" (i.e., ARP/NC allows
only to identify active interfaces).
Correct?
Best regards,
JMC.
</JMC>
Ron
>
> <JMC>
> Question:
> Why the A-bit is not set when Code Field is equal to Multiple Interfaces
> Satisfy Query (3) and the L-bit is clear? Question: Same question when L-bit
> is
> set. </JMC>
>
> <snip>
>
[RB ]
Error code 3 (Multiple Interfaces Satisfy Query) means that they query is
ambiguous. Or, on other words, that two or more interfaces satisfy the match
conditions specified by the query. So, we can't set the A, F, S or E bits
because we don't know which interface the user is asking about.
<JMC>
But, even if this is ambiguous, IMHO, all the interfaces are active => A-bit
should be set
And Error Code 3 returned to probing interface raises this is ambiguous.
Now, I am OK that F, S and E should be cleared to avoid any confusion between
the different interfaces.
Did I miss something?
</JMC>
<snip>
Best regards,
JMC.
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