[zebra 23025] Re: Selective route advertisement

Hi David,
Thanks a lot for the information. Thats absolutely right.
Is there any way to filter out the link state advetisements from
a particular neigbour/neighbours if all are in the same area? Because
I dont want to make my routing table flooded with so many routes which
I'm not interested in. Any pointers?
Thanks,
Adityaa


On 5/8/07, David Schwartz <[email protected]> wrote:
>
>
> > Hi,
> > Is there any way to do selective route advertisement
> > with Zebra ospfd?
> > Basically, I want zebra ospf router not to advertise
> > the routes it learned from
> > a particual interface to another interface.
>
> This violates fundamental design criteria of OSPF. Routes are not really
> advertised to other routers in the same area so much as they are
> synchronized, and that areas are fully synchronized is a primary design
> attribute of OSPF.
>
> For example, OSPF avoids routing loops because every router in an area
> knows
> exactly what every other router in that area will do because their routes
> for that area are synchronized. If you could suppress routes within an
> area,
> routing loops could occur.
>
> >Zebra router --------- interface 1 ------------ router1 - Network 1
> >           |
> >           --------- Interface 2 ----------- router2 - Network 2
> >
> >I dont want router to forward the network 1 route to router 2.
>
> You are fundamentally misunderstanding what OSPF *is*. OSPF is a link
> state
> protocol. It advertises the state of links. You are trying to get it to
> advertise paths, and that's just not OSPF.
>
> What you are asking for, if it were possible, would be a disaster. See
> this
> web page:
> http://blogs.sun.com/paulj/entry/why_can_t_i_filter
>
> The short answer is: OSPF advertises links, not routes, so it cannot
> advertise routes selectively.
>
> DS
>
>
>

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