From: Dale Kling (dalek77@gmail.com)
Date: Sun Jun 01 2008 - 13:40:51 ART
Yes, tagging is the easiest to prevent route feedback, for me anyway, it's
not always needed though. Administrative distance plays an important factor
in route feedback as well as other routing path decisions. Sounds like the
concept of how administrative distance effects redistribution on a router
would payoff greatly for you. The IE Blogs on redistribution are excellent
for your questions and I would highly read and study all 3 parts for a great
understanding. I've read them 3 times each myself.
regards,
Dale
On Sun, Jun 1, 2008 at 12:29 PM, Usama Pervaiz <chaudri@gmail.com> wrote:
> The reason I asked the question was because I was doing one of IE labs
> (lab 1 actually). Even though mutual redistribution was being done on
> two routers, no route tags were defined and nothing was being blocked.
> This is what I did:
>
> ON R3:
>
> router eigrp 100
> redistribute ospf 1 metric 1500 1 255 1 1500 route-map RED-OSPF
> network 183.5.123.0 0.0.0.255
> no auto-summary
> !
> router ospf 1
> router-id 3.3.3.3
> log-adjacency-changes
> redistribute eigrp 100 subnets route-map RED-EIGRP
> network 150.5.3.3 0.0.0.0 area 0
> network 183.5.0.3 0.0.0.0 area 0
>
> route-map RED-EIGRP deny 10
> match tag 110
> !
> route-map RED-EIGRP permit 20
> set tag 170
> !
> route-map RED-OSPF deny 10
> match tag 170
> !
> route-map RED-OSPF permit 20
> set tag 110
>
>
> ON R5:
>
> router eigrp 100
> redistribute ospf 1 metric 1500 1 255 1 1500 route-map RED-OSPF
> network 183.5.105.0 0.0.0.255
> distance eigrp 120 170
> no auto-summary
> !
> router ospf 1
> router-id 5.5.5.5
> log-adjacency-changes
> redistribute eigrp 100 subnets route-map RED-EIGRP
> network 150.5.5.5 0.0.0.0 area 0
> network 183.5.0.5 0.0.0.0 area 0
> network 183.5.45.5 0.0.0.0 area 45
> neighbor 183.5.45.4
>
> route-map RED-EIGRP deny 10
> match tag 110
> !
> route-map RED-EIGRP permit 20
> set tag 170
> !
> route-map RED-OSPF deny 10
> match tag 170
> !
> route-map RED-OSPF permit 20
> set tag 110
>
>
> Is this the proper way of blocking the routes from redistributing into
> their original routing domain? Is this a "best practice"? Is this what
> is expected in the lab?
>
> Any and all help will be appreciated!
>
> Thanks,
> Usama
>
>
>
>
>
>
> On Sun, Jun 1, 2008 at 2:19 AM, attia mohamed <ahmattia78@yahoo.com>
> wrote:
> > hi
> > i asked that question to a ccie certified person so he told me that there
> is a differnce between loop prevention and mutual redistibution as
> redistribution on one router donot make loop but on two routers may make
> loop .
> > so making tag on the same router that mean mutal redistribution making
> tagging with two routers is loop prevention ( same routing protocol)
> >
> >
> >
> > --- On Sat, 5/31/08, John <jgarrison1@austin.rr.com> wrote:
> >
> >> From: John <jgarrison1@austin.rr.com>
> >> Subject: Re: Route redistribution question
> >> To: "Usama Pervaiz" <chaudri@gmail.com>, "Cisco certification" <
> ccielab@groupstudy.com>
> >> Date: Saturday, May 31, 2008, 5:35 PM
> >> This is a good article on the subject
> >>
> >>
> http://blog.internetworkexpert.com/category/ccie-routing-switching/interior-gateway-routing/
> >> ----- Original Message -----
> >> From: "Usama Pervaiz" <chaudri@gmail.com>
> >> To: "Cisco certification"
> >> <ccielab@groupstudy.com>
> >> Sent: Saturday, May 31, 2008 2:49 PM
> >> Subject: Route redistribution question
> >>
> >>
> >> > Hello all,
> >> >
> >> > I have a quick question on redistribution. I apologize
> >> if this has
> >> > been asked already.
> >> >
> >> > I have two routers lets say R1 and R2 both with two
> >> interface fa0/0
> >> > and fa0/1 (for simplicity). R1 fa0/0 and R2 fa0/0 are
> >> both in OSPF and
> >> > are in area 0 (there are other routers in the middle)
> >> that would make
> >> > both R1 and R2 ASBR's. R1 fa0/1 and R2 fa0/1 are
> >> both in EIGRP AS 100.
> >> > At this point all connectivity is there and everything
> >> is well within
> >> > the area and AS.
> >> >
> >> > Now if I do mutual redistribution on both R1 and R2 do
> >> I have to tag
> >> > the routes and block them on the other router? i.e. I
> >> redistributed
> >> > EIGRP into OSPF on R2 do I tag these routes with 90
> >> (for simplicity)
> >> > and on R1 block these routes from re-redistributing
> >> into EIGRP on R1?
> >> > Will it even redistribute these routes into EIGRP
> >> again even if I
> >> > don't?
> >> >
> >> > Any and all help would be appreciated and sorry for
> >> being so long winded!
> >> >
> >> > Thanks,
> >> > Usama
> >> >
> >> >
> >> >
> >> _______________________________________________________________________
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> >>
> >>
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> >
> >
> >
> >
>
>
>
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