[c-nsp] Reliable static routes and 12.2S

[Rodney Dunn]

I finally got time to think about this again.

What deployment scenario would this be for.

BFD is supposed to be a way to notify the upper
layer protocols of a forwarding failure faster.

For a DSL type environment you usually are not running
a routing protocol over the links so what do you want
to react?

Rodney

On Wed, Dec 22, 2004 at 09:46:46AM +0100, Andre Beck wrote:
> On Tue, Dec 21, 2004 at 05:04:51PM +0100, Daniel Roesen wrote:
> > On Tue, Dec 21, 2004 at 04:19:05PM +0100, Andre Beck wrote:
> > > Well, supervising reachability on top of VPNs and PPPoE clouds is
> > > the real intention, but in practice, every simple Ethernet broadcast
> > > domain with a gateway in there is able to blackhole you. I'd rather
> > > like an alternate style of L2 reachability supervision on top of
> > > Ethernet, a special non-ARP point to point over Ethernet that
> > > constantly watches the availability of the peer MAC and would let
> > > the interface go line protocol down if it cannot be established. But
> > > there is no such thing that I knew of,
> > 
> > You're looking for BFD (bi-directional forwarding detection). As far as
> > I know not yet implemented by Cisco, and in JunOS only used for IGP
> > yet (IS-IS, not sure about OSPF). Provides end2end failure detection
> > down to milliseconds time-to-detect (I've seen 50ms - this is SONET/SDH
> > ring wrap time).
> 
> Thanks for the pointer. That reads almost exactly like what I thought
> up some days ago during a boring meeting, just way more orthogonal
> and medium independend. Hopefully this will end up in IOS soon, as the
> draft is headed by Cisco as well as Juniper. Ideally in Ethernet
> subinterface mode like
> 
> int fa0/0.33
>  encapsulation bfd 33
>  ip unnumbered fa1/0
>  keep 4
> 
> with 33 beeing the discriminator for that PtP link. Of course you would
> normally want that to be numbered with a transit net for IGP/EGP use,
> but in BFD context it SHOULD support unnumbered IMO - for the potentially
> vast amount of RBE customer fanouts in xDSL world.
> 
> Thanks,
> Andre.
> -- 
>                   The _S_anta _C_laus _O_peration
>   or "how to turn a complete illusion into a neverending money source"
> 
> -> Andre Beck    +++ ABP-RIPE +++    IBH Prof. Dr. Horn GmbH, Dresden <-
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