From: Carlos G Mendioroz (tron@xxxxxxxxxxx)
Date: Fri Jun 21 2002 - 16:40:46 GMT-3
Hmm,
if you had a hook, you could do it. Conditional advertising does let you
do what
I want from the BGP side. The problem is that HSRP does not tell you at
level 3
which is your active router for your network!
But I have been thinking and found no way to tell. No new networks, no
interface
status, no nothing :-(
P729 wrote:
>
> You can't really "prevent" it. While you can control how traffic leaves your
> network, you can only influence how traffic comes to your network to a
> limited degree, as in sending BGP MEDs (which are often ignored), prepending
> your AS-path or perhaps sending well-known communities.
>
> Depending on your arrangement with your ISP, you'll pretty much have to talk
> them into traffic engineering the path(s) taken by traffic destined for your
> network from the Internet-at-large. It's more feasible if all of your
> traffic comes via one ISP, but it becomes more difficult (perhaps totally
> impractical) when two or more are involved and you aren't taking full
> routes.
>
> Regards,
>
> Mas Kato
> https://ecardfile.com/id/mkato
> ----- Original Message -----
> From: "Carlos G Mendioroz" <tron@huapi.ba.ar>
> To: "Groupstudy ccielab list" <ccielab@groupstudy.com>
> Sent: Friday, June 21, 2002 11:18 AM
> Subject: Re: HSRP: the other side ?
>
> > It seems I'm not making an interesting thing out of this :-(
> >
> > Say you have 2 routers like before, but one has a 100Mbit interface
> > and is the preferred access, and the other is an old 4000 with only
> > 10Mbit interface, but you do HSRP between them not to have a
> > single point of failure on the router. Obviously you don't want
> > your traffic to come via the 10Mbit half duplex interface to your lan.
> >
> > How would you prevent it ?
> >
> > Carlos G Mendioroz wrote:
> > >
> > > I'm still looking for a way to solve what I think is a problem ;-)
> > > Namely, you have a network and a couple of routers doing HSRP
> > > for providing redundant exit path to the rest of the world.
> > >
> > > As I see it, this has two sides.
> > >
> > > 1) The inside:
> > > HSRP solves the redundancy by using a polling mech (HSRP) to
> > > identify which router out of a group is responsible for the
> > > group MAC and IP. Every host on the net uses this MAC/IP to
> > > go out. It works and actually can deal with many problems
> > > (with track you can even react to some external problems).
> > >
> > > 2) The outside:
> > > The rest of the world need to know how to reach your network.
> > > And here, AFAIK HSRP has no hooks to make this easy.
> > >
> > > E.g.
> > >
> > > N -- R1 -- wan link to ISP
> > > E
> > > T -- R2 -- backup wan link to ISP
> > >
> > > When R2 turns active, how does it signal ISP that now traffic to your
> > > net
> > > should be forwarded to it (instead of to R1) ?
> > >
> > > It's easy if R1's net interface went down, but it might not be the
> > > case...
> > >
> > > Comments ?
> > > I have some weird ideas, but would like to know if there is an orthodox
> > > way out.
> > >
> > > --
> > > Carlos G Mendioroz <tron@huapi.ba.ar> LW7 EQI Argentina
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