From: Michael Snyder (msnyder@revolutioncomputer.com)
Date: Tue Nov 18 2003 - 20:15:02 GMT-3
I can't seem to figure out your topo.
Use a fixed font in notepad, then paste it to your email.
But in general, these questions come to mind.
1) Is it a tag problem or a redistribution problem? An example here is
rip. If it's not in the route table, rip won't redistribute it.
2) Because we are using tags for loop control, your ospf redistributions
should be wide open. Internal, external, nssa, subnets all should be
candidates for redistribution.
3) The strategy I posted isn't a fix all. It's just a standardized loop
control for over multiple redistribution points. Any inherent route
problems in the labs will still show up.
Do a show ip route summary on each router. If you can't explain why the
total number of subnets isn't the same per router, you have bigger
problems to worry about.
Thought you do have a lot of control with distribute lists and
route-maps. I've even tagged one route, and made exception (like a port
thru a firewall) for that route to transverse my standard route-map
statements.
Route-map into_core permit 3
Match ip address 'single weird route'
route-map into_core deny 5
> match tag 222
>!
>route-map into_core permit 10
> set tag 111
Hope that helps.
Michael
-----Original Message-----
From: Silvio Nunes [mailto:silvio_98@hotmail.com]
Sent: Tuesday, November 18, 2003 4:40 PM
To: ccielab@groupstudy.com
Cc: dansheedy@gmx.net
Subject: RE: Tags and Redistributing
Hi Michael,
Consider the following situation:
|
|
|.........(EIGRP-AS1) R2
(OSPF).......|
R4 (RIP)...... R7(EIGRP-AS1).......|
|
|
|..............(OSPF) R1
|........(EIGRP-AS1) R3
(OSPF) ...... |
|
|
I configured this topology with your template, but is not working
properly
for this situation:
In this case, R2 and R3 get the route advertised from RIP as next-hop
R1,
this is because these routes have administrative distance 170 and OSPF
110.
With your strategy, is there another way without modify OSPF Admin
Distance
or with distribute-list ?
I configured route-maps on R2 and R3, with TAGs for EIGRP and OSPF.
Regards,
>From: "Michael Snyder" <msnyder@revolutioncomputer.com>
>Reply-To: "Michael Snyder" <msnyder@revolutioncomputer.com>
>To: <ccielab@groupstudy.com>
>CC: "'Daniel Sheedy'" <dansheedy@gmx.net>
>Subject: RE: Tags and Redistributing
>Date: Tue, 18 Nov 2003 09:53:53 -0600
>
>Been doing this awhile.
>
>
>This the template I use. The first statement blocks what I don't want.
>The second statement sets everything that was allowed in to a new tag
>value, for later use.
>
>--------------------------------------------------
>
>route-map into_core deny 5
> match tag 222
>!
>route-map into_core permit 10
> set tag 111
>
>--------------------------------------------------
>
>
>route-map into_core deny 5
> match tag 111
>!
>route-map away_from_core permit 10
> set tag 222
>
>--------------------------------------------------
>
>
>Two way tagging away from core isn't always necessary away from the
core
>igp, but tagging into the core is necessary.
>
>Use different tags for different igp's, for example.
>
>R1 - rip to ospf tags 111 & 222
>
>R5 - eigrp to ospf tags 333 & 444
>R6 - eigrp to ospf tags 333 & 444
>
>Note I used the same tags, because it was the same eigrp as touching
the
>ospf igp
>
>R8 - isis to ospf tag 555 (into ospf)
>
>(note) I only tagged incoming isis2ospf because isis doesn't seem to
>like tags. On the other hand, I can block 555 from going back into
>isis.
>
>
>In summary, now ospf has tags 111, 333, 555 in the core igp, and is
>blocking the 111 tag from going into rip, the 333 tag into either
eigrp,
>and the 555 tag from going into isis. Any value not blocked, is set to
>a new tag on the other side.
>
>For example
>
>Anything that makes it into rip is tagged 222, and into eigrp 444.
>
>Which is also blocked from going back into ospf at the respectful
>routers.
>
>
>
>
>
>
>
>
>!
>
>-----Original Message-----
>From: Daniel Sheedy [mailto:dansheedy@gmx.net]
>Sent: Tuesday, November 18, 2003 7:35 AM
>To: ccielab@groupstudy.com
>Subject: Tags and Redistributing
>
>Hi Guys,
>
>I've been doing some research into Tags and Redistribution. I am using
>them
>to prevent routing loops, and have a little question in regards this.
>If i
>do a 'match tag X' while redistributing, do I need to also do a 'set
tag
>X'
>or does the tag stay with the route through the redistributions?
>
>Thanks
>
>Daniel Sheedy
>
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