Your right..im out of it this morning..i though it
said receive, which wouldn't make sense anyways...
--- Avram Dorfman <avram@juniper.net> wrote:
> That's what the "resolve" keyword is for. It allows
> the next-hop to be
> resolved through the routing table. It's called a
> recursive static
> route. Some other brands call it a "floating"
> static. It's available as
> of 5.2.
>
> -Avram
>
> -----Original Message-----
> From: HHH
> To: Bruce Cole; Eric Mellott
> Cc: juniper-nsp@puck.nether.net; Bruce Cole
> Sent: 5/2/2002 6:08 AM
> Subject: Re: Juniper equivalent of Cisco's BGP
> Conditional
> Advertisements
>
> next-hop address needs to be directly connected to
> the
> router with a static route to be active, and policy
> only evaluates active routes.
>
> --- Bruce Cole <cole@juniper.net> wrote:
> > > Does anyone know if and how Juniper implements
> > something similar to Cisco's
> > > BGP Conditional Advertisements. Cisco's
> > Conditional advertisement is
> > > useful in a multihomed network, in which some
> > prefixes are to be advertised
> > > to one of the providers, only if information
> from
> > the other provider is
> > > missing. This condition would indicate a failure
> > in the peering session, or
> > > partial reachability. So, basically routes are
> > advertised only if other
> > > routes disappear from table.
> >
> > I didn't see an actual answer to this question so
> > let me try.
> >
> > I don't know of anything in our routing policy
> that
> > would provide
> > the exact same functionality as cisco's
> conditional
> > advertisement.
> > However you may be able to achieve what you are
> > looking for by
> > using static routes with the resolve keyword.
> > For example, if the prefix you wish to advertise
> is
> > 3/8 you
> > could configure:
> >
> > routing-options {
> > static {
> > route 3.0.0.0/8 {
> > next-hop x.x.x.x;
> > resolve;
> > }
> > }
> > }
> >
> >
> > where x.x.x.x is an IP address that is chosen out
> of
> > the address space
> > that is advertised by one of the two providers.
> > (Perhaps x.x.x.x is
> > an address from your link to the provider, or
> maybe
> > it is a more
> > specific than one of the prefixes you expect to
> > learn from this
> > provider.)
> >
> > Lets assume that you also learn of 3/8 via BGP,
> and
> > export that
> > prefix to the backup provider via the policy:
> >
> > from {
> > protocol bgp;
> > route-filter 3.0.0.0/8 exact;
> > }
> > then accept;
> >
> > When the static route is active, you'll wind up
> not
> > advertising the
> > prefix since the protocol match fails. When the
> > x.x.x.x address
> > is missing, the static route goes inactive, and
> you
> > advertise 3/8
> > due to the protocol matching.
> >
> > Depending upon what you want in your RIB and FIB,
> > you might want
> > to get more complicated, perhaps writing an export
> > policy that matches
> > on the next-hop instead.
> >
>
>
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This archive was generated by hypermail 2b29 : Mon Aug 05 2002 - 10:42:35 EDT