The MPLS WG Archive

["Thomas D. Nadeau" <tnadeau@cisco.com>]

At 07:13 AM 3/21/2002 -0800, Shahram Davari wrote:
> > -----Original Message-----
> > From: Thomas D. Nadeau [mailto:tnadeau@cisco.com]
> > Sent: Thursday, March 21, 2002 9:35 AM
> > To: Shahram Davari
> > Cc: 'mpls@uu.net'
> > Subject: RE: Y.1711 requirements from IETF
> >
> >
> > At 03:31 PM 3/20/2002 -0800, Shahram Davari wrote:
> > >Thomas,
> > >
> > >
> > > > > >
> > > > > >          You should be clear. It specifies that *all*
> > LSPs must be
> > > > > > provisioned with this feature
> > > > > > on and at a specific interval.
> > > > >
> > > > >
> > > > >Where did you get this " ALL LSPs MUST" statement from? May
> > > > be you are
> > > > >reading a different Y.1711 than I have. All I can find are
> > > > the following
> > > > >statement:
> > > > >
> > > > >" ... It is strongly recommended that CV OAM packets be
> > > > generated on all LSPs
> > > > >(in order to detect all defects and potentially provide
> > > > protection against
> > > > >traffic leakage both in and out of LSPs). "
> > > > >
> > > > >"... CV generation could be enabled on all (or most) of the LSPs"
> > > > >
> > > > >There is no MUST and in fact you could enable the CV
> > only on ONE LSP.
> > > > >If the text is not conveying this information, then we would have
> > > > >to add additional text or appendix in the next version
> > to clarify it.
> > > >
> > > >          The text at strongly implies that it should be run
> > > > everywhere all
> > > > the time.
> > > > Not knowing the ITU language mapping from IETF MUST, MAY or
> > > > SHOULD, it is a reasonable assumption that the text you refer to
> > > > requires OAM to be run on every LSR and on every LSP.
> > > >
> > >
> > >I think you are imagining things. Now you added one more
> > imagination to your
> > >comments : "..requires OAM to be run on every LSR". Where
> > did you get this one
> > >from?
> > >
> > >For clarification OAM needs to be run only on edge LSRs, and
> > you could
> > >turn it on or off on any LSP that you want.
> >
> >          Two points. First, rarely is an LSR just an LSR, the argument
> > that this  needs to run "only on edge LSRs" could in reality mean
> > that it needs to run on every or nearly every LSR in a
> > provider network.
> > Second, given the fact that many LSRs that also have PE
> > functionality also
> > contain the entire Internet routing database when running LDP for LSP
> > tunnels, running this on devices doing edge duty at the "strongly
> > recommended" rate of 1 ping per LSP has ramifications for
> > network bandwidth
> > on potentially every device.  Again, I recommend scaling back your
> > "strongly recommended" terminology, as it is clear that this is not
> > a solution that fits all networks.
>
>But the same argument applies to MPLS-ping too. You also need to upgrade 
>all LSRs.

         You only have to patch the software for LSP Ping. With your
approach, hardware re-spin is required.

         --Tom




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