Re: My virtual-link question

[Don Goodspeed <Don.Goodspeed at ALCATEL.COM>]

Mitchell,

Knowing that, I can now re-read your email and it makes
complete sense now.  MaxAge'ing the LSA on the "overload"
router so NO paths are built thru it.

Thanks,
Don

-----Original Message-----
From: Mailing List [mailto:OSPF at PEACH.EASE.LSOFT.COM]On Behalf Of
Erblichs
Sent: Friday, July 30, 2004 6:37 PM
To: OSPF at PEACH.EASE.LSOFT.COM
Subject: Re: My virtual-link question


Don,

        I was talking about two general methods
        of handling overload, thus it was a FYI...

        Doing one, both, or none is a implimentation
        issue for your company.

        Mitchell Erblich
        ----------------

Don Goodspeed wrote:
>
> Mitchell,
>
> Why would a router advertising a virtual-link as one of it's
> possibly many links MaxAge it's entire router LSA?
>
> And in the example that I gave, the router with the virtual-
> link was not the one in overload.  In fact, I made a note
> at the end of my original description that one could have
> a virtual-link path where the total path cost exceeded 65535
> and my question applied to that scenario as well.
>
> Should the end-points of the virtual-link tear down the
> virtual-link in this case, or advertise the virtual-link
> with the largest advertisable cost in a TOSMetric field
> of a router LSA which is 65535.
>
> I think you and I are thinking of two different scenarios.
>
> Cheers,
> Don
>
> -----Original Message-----
> From: Mailing List [mailto:OSPF at PEACH.EASE.LSOFT.COM]On Behalf Of
> Erblichs
> Sent: Friday, July 30, 2004 6:20 PM
> To: OSPF at PEACH.EASE.LSOFT.COM
> Subject: Re: My virtual-link question
>
> Don,
>
>         MAXAGE is used to withdraw a link from the LSDB.
>         It is normally done when the SEQ is Maxed out.
>
>         If a router is indeed OVERLOADED and unable to
>         route even the fewest of transit packets and/or
>         dst packets, then it is easily concieveable not
>         to waste the bandwidth of to the destinations
>         knowing those packets are going to be dropped
>         anyway. Worst case is a drop at the last hop.
>
>         You are in effect voluntering blackholing those
>         routes until your router is able to advertise them
>         again. It is a very drastic move which forces a new
>         convergence to take place. It also assumes that
>         you can still generate the advertisement. The same
>         will happen if you don't refresh the routes in
>         1 hours timeframe.
>
>         Please be aware that this is different from DNA
>         (do not age) LSAs.
>
>         The MAXCOST metric via the Stub Router Advertisement
>         only minimizes the number of transit pkts, but with
>         no alternatives does not decrease the amount of
>         transit traffic. It does not effect pkts that are
>         routed only to a dst that is attached thru the
>         router.
>
>         I thought you would like to see how to do both of
>         your items.
>
>         Mitchell Erblich
>         -------------------
>
> Don Goodspeed wrote:
> >
> > All,
> >
> > My excite account was on the fritz so I resubscribed with my work
account.
> >
> > Mitchell, the last email I saw said advertise the link with MAXAGE.
> >
> > Did you mean to say MaxMetric (aka 0xffff)?
> >
> > -don