[j-nsp] Route redistribution

From: Kent Yu (yux@lucent.com)
Date: Mon May 14 2001 - 14:33:44 EDT


All,

Junipers route redistribution concept really confuses me.
By definition, routes from the protocols are imported into the routing
table, then exported to their respective routing protocols. I then found
followin from Juniper docs CD:

Define a policy that takes BGP routes from the Edu community and places them
into IS-IS with a metric of 14. Apply the policy to routes exported from the
routing table into IS-IS.

 protocols {
          isis {
                   export edu-to-isis;
          }
 }
 policy-options {
          community Edu members 666:5;
          policy-statement edu-to-isis {
                   from {
                            protocol bgp;
                            community Edu;
                   }
                   to protocol isis;
                   then metric 14;
          }
 }

So in order to redistribute routes, I will have to use policy, right?
But to me, isnt policy only used to filter routes that already exist? I
mean, by default, there should no routes from bgp to ISIS, so to what routes
the above policy applied? Or can I understand as that the policy
configuration actually activates redistribution? If it is, I must say it is
really confusing, at least to me.
Also, the manual states: For IS-IS, you should not apply routing policies
that affect how routes are imported into the routing table; doing so with a
link-state protocol could easily lead to an inconsistent topology database.

If I am not wrong, cisco does not allow outbound filters for link state
protocols, but inbound filters are working, you just can filter LSPs. But
here in Juniper, why not inboud? I would imagine the propagation of LSPs
should not have anything to do with the interaction between routing
protocols and the local routing table, should the protocols forward te LSPs
themselves?

I also found the Juniper documentation is really poor, not too many working
examples on the website.

Thanks
Kent

----- Original Message -----
From: "Adagio Vangogh" <adagio_v@pacbell.net>
To: "Rob Heath" <rheath@c-pro.net>
Cc: <juniper-nsp@puck.nether.net>
Sent: Saturday, April 28, 2001 9:29 AM
Subject: Re: mixing 802.1q and 802.3 or type II interfaces

> Rob Heath wrote:
>
> > Hi Adagio,
> >
> > Yes you can have multiple logical interfaces on the same ethernet
interface
> > be they tagged or not, see:
> >
> >
http://www.juniper.net/techpubs/software/junos44/swconfig44-interfaces/html/
interfaces-ethernet-config10.html#1013155
> >
>
> OK, I'm confused. You mean that I could have multiple logical interfaces
even
> without vlan encapsulation?
>
> Thanks,
>
> Adagio



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