[j-nsp] Filtering OSPF routes

[Kent Yu]

IOS only allows filtering type-3 at ABR, I think the original poster's
intend was to filter LSA within the same area.

The IOS feature could be useful for enterprise networks, do not think it is
helpful for the SPs.

Thanks
--kent
----- Original Message -----
From: "Wayne (juniper nsp)" <wg-jnpr-nsp at wgustavus.com>
To: "Elliott, Andrew" <AElliott at xo.com>; "'Ben Buxton'"
<B.Buxton at Planettechnologies.nl>; "'Ajay Bhardwaj'"
<ajay.bhardwaj at in.spectranet.com>; <juniper-nsp at puck.nether.net>
Sent: Tuesday, February 18, 2003 12:07 PM
Subject: Re: [j-nsp] Filtering OSPF routes


RE: [j-nsp] Filtering OSPF routesOk,

On the off chance that it wasn't clear in my original post when I said
"contrary to the design of OSPF (or any link state

protocol)", I am NOT advocating anyone doing this. I am simply pointing out
that Cisco IOS provides a knob to do what he described.

- Wayne



  ----- Original Message -----
  From: Elliott, Andrew
  To: 'Wayne (juniper nsp)' ; 'Ben Buxton' ; 'Ajay Bhardwaj' ;
'juniper-nsp at puck.nether.net'
  Sent: Tuesday, February 18, 2003 10:26 AM
  Subject: RE: [j-nsp] Filtering OSPF routes


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  Wayne,

  I have seen this in action, and it is ugly.

  I recently had to work on a Cisco network where all routers were in
  one of two areas, and they were using the distribute-lists to only
  use the 0/0 LSA.  This created many routing loops, and I asked the
  "designer" what they were thinking, and basically got the cold
  shoulder.  I couldn't understand why someone would want to use OSPF
  and then deliberately break it in that manner.

  Has anyone on this list ever seen a good reason to filter LSAs?

  - -andrew

  - -----Original Message-----
  From: Wayne (juniper nsp) [mailto:wg-jnpr-nsp at wgustavus.com]
  Sent: Saturday, February 15, 2003 11:43 PM
  To: Ben Buxton; Ajay Bhardwaj; juniper-nsp at puck.nether.net
  Subject: Re: [j-nsp] Filtering OSPF routes




  Actually, if you are running a sufficiently high enough version of
  IOS (e.g. 12.0S), the 7200 can filter some LSAs.  It depends on your
  exact scenario if this will accomplish what you are trying to do.  It
  does tend to go contrary to the design of OSPF (or any link state
  protocol), but I suppose enough people wanted the knob, so they got
  it.

  Not sure if JUNOS has a similar knob.

  - - Wayne

  - ----- Original Message -----
  From: Ben Buxton
  To: Ajay Bhardwaj ; juniper-nsp at puck.nether.net
  Sent: Monday, February 10, 2003 4:18 AM
  Subject: RE: [j-nsp] Filtering OSPF routes


  You cannot filter OSPF. This would break the requirement that all
  routers have
  the same link state view.
  This is true for both Junos and IOS.

  BB

  - -----Original Message-----
  From: Ajay Bhardwaj [mailto:ajay.bhardwaj at in.spectranet.com]
  Sent: Monday, 10 February 2003 08:39
  To: juniper-nsp at puck.nether.net
  Subject: [j-nsp] Filtering OSPF routes



  Hi all,

  We have cisco 7200 router and M-5 router both running ospf and part
  of area 10.

  I want to deny few routes which are flowing trough ospf from 7200 to
  m5 either at 7200 side or m5 side. Pls if anyone have any solution to
  this would be gr8 help for me.

  Ajay Bhardwaj




    _____





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