On 7/26/07, Shane Amante <[EMAIL PROTECTED]> wrote:
>
> Mark,
>
> Mark Townsley wrote:
> >
> > Please also give us feedback on whether or not this document should be
> > published, and on what track. I am considering the Standards Track,
> > shepherded directly by either me or Jari.
>
> I would support Standards Track.
>
> In addition, Alia and I have been speaking about another use case for
> this draft.  In particular, I would like to see it extended to account
> for identification of component-links inside ECMP and LAG's, which
> should be a straightforward use case given what's already specified in
> this draft.  This use case has become prevalent over the last several
> years and will become even more so in the future.


I believe that these cases can be handled by the router deciding which
ifIndex or IP address to include.  For instance, a router might include the
ifIndex of the member interface of a LAG.

Alia


-shane
>
>
> > - Mark
> >
> > Alia Atlas wrote:
> >> I have updated the draft to reflect its goal of providing better
> >> identification of the receiving interface to aid in troubleshooting
> >> with traceroute.
> >>
> >> There are a few common scenarios that this draft is intended to help
> >> with.
> >>
> >> First, the receiving interface may be different than the outgoing
> >> interface (which gives the source IP address in the ICMP packet)
> >> because of either asymmetric link costs or ECMP.
> >>
> >> Second, the receiving interface may be unnumbered, so that the source
> >> IP address can't identify the interface.  This is a problem for
> >> troubleshooting when there are parallel unnumbered links.
> >>
> >> I would welcome any comments or discussion on this draft.
> >>
> >> Thanks,
> >> Alia
> >>
> >>
> >>
> >>
> >> On 5/15/07, *Alia Atlas* <[EMAIL PROTECTED]
> >> <mailto:[EMAIL PROTECTED]>> wrote:
> >>
> >>     On 5/14/07, *Pekka Savola* <[EMAIL PROTECTED]
> >>     <mailto:[EMAIL PROTECTED]>> wrote:
> >>
> >>         On Mon, 14 May 2007, Alia Atlas wrote:
> >>         > In general, I find the specification having features that I
> >>         don't see
> >>         >>  necessary. Reporting ifIndex is not necessary (and the
> >>         index is not
> >>         >>  very useful as is to a human) if ifName is
> >>         reported.  Addresses are
> >>         >>  already known from the source address though somewhat less
> >>         reliably so
> >>         >>  those need not be reported for outgoing interface use, and
> >>         could also
> >>         >>  result in reporting IPv6 link-local addresses (or IPv4
> >> private
> >>         >>  addresses) which wouldn't necessarily be useful or desired.
> >>         >
> >>         > The idea with reporting the ifIndex is to provide the easy
> >>         ability
> >>         > to correlate that to MIB data.  It is a common look-up key
> >> and I
> >>         > believe it to be useful.
> >>         >
> >>         > Using simply the source address doesn't handle topologies
> with
> >>         > parallel links between routers.  In that case, knowing the
> >> exact
> >>         > outgoing link for troubleshooting is useful. ...
> >>
> >>         (A potentially interesting note: at least one implementation
> >>         has an
> >>         internal 'interface index' which is different from 'SNMP
> >> ifIndex'.
> >>         The intent should be clear in the spec.)
> >>
> >>
> >>     Do you have improved phrasing you might suggest?
> >>
> >>         If ifName is reported, is there significant benefit in
> reporting
> >>         ifIndex as well?
> >>
> >>         It could be more easily used for correlation, but that's only
> >>         useful
> >>         for the operators of the network who could know the ifIndexes
> >>         on the
> >>         routers, not outsiders.  On the other hand, those network
> >>         operators
> >>         can very well map the ifName to ifIndex using SNMP or similar
> >>         tools as
> >>         well.
> >>
> >>
> >>     True -  I guess some of it depends whether the name or ifIndex is
> >>     more private
> >>     and how many steps an operator has to take to get decent results.
> >>     On the other hand, normal traceroute gives both the IP address and
> >>     the DNS
> >>     name, if any.  I was looking to provide the equivalent.
> >>
> >>         I'm not strongly against being able to report ifIndex (but I'd
> >>         rather
> >>         that it doesn't get reported by default, at least to
> >>         everyone), but it
> >>         seems like a feature that's more likely to clutter the
> traceroute
> >>         output with little added value: ifName should already provide
> >>         the same
> >>         benefits and is a more generic mechanism.
> >>
> >>
> >>     All of the additional info is optional and an operator could
> >>     determine what
> >>     to show based upon the incoming IP address or such.
> >>
> >>     Again, I was going for duplicating the information provided if an
> >>     IP address existed.
> >>
> >>     Alia
> >>
> >>
> >>
> ------------------------------------------------------------------------
> >>
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> >>
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