From: Harish DV/peakxv (harish.dv@xxxxxxxxxx)
Date: Thu Jul 25 2002 - 19:52:45 GMT-3
Tom,
Have a look at this
http://www.groupstudy.com/archives/ccielab/200201/msg01743.html
This seems more elegant to me when doing mutual redistribution with
protocols which don't support tagging.
"Tom Larus"
<tlarus@cox.net> To: "Harish DV/peakxv" <ha
rish.dv@peakxv.net>, "Perminder Grewal"
Sent by: <percy_gunner@hotmail.com>
nobody@groupstudy cc: <ccielab@groupstudy.co
m>, <Mark.Snow@newcome.com>, <nobody@groupstudy.com>
.com Subject: Re: CCIE Practical Stu
dies, Darth Reid, and Redistribution
07/25/2002 02:40
PM
Please respond to
"Tom Larus"
He tagged the IGRP and RIP routes as they were redistibuted INTO OSPF. I
do
this all the time.
I like tagging to stop route feedback (at least one way) a lot, but it is
not the cure-all. Caslow said in class that tagging is elegant and
scalable, and taught us how to adjust the AD to prevent some unwanted
results on the redistributing router (you know, from the routing protocol
with lower AD taking over all the routes on teh router as its own)
That made me feel better about using tagging, but the problem is that this
one-way tagging does not stop an OSPF route that was redistributed into
IGRP
from being redistributed back into OSPF. I have not figured how big a
problem this except, that it was deadly the other day when IGRP shortened
the prefix and then redistributed an originally-OSPF route back into OSPF.
The underlying problem was that split horizon needed to be disabled on a
router in the IGRP domain. (That experience has been discussed to death
here).
I wish someone could assure me that one-way tagging, with appropriate
distance adjustment, is adequate. I think I will need to get more practice
doing redistrubution with distribute-lists, which seems to be the more
well-established way of prventing route-feedback. Granular control is more
important in the lab exam than scalability and elegance (or redundancy,
even). I am scared to death of missing or fat-fingering a network number,
though.
----- Original Message -----
From: "Harish DV/peakxv" <harish.dv@peakxv.net>
To: "Perminder Grewal" <percy_gunner@hotmail.com>
Cc: <ccielab@groupstudy.com>; <Mark.Snow@newcome.com>;
<nobody@groupstudy.com>
Sent: Thursday, July 25, 2002 2:02 PM
Subject: Re: CCIE Practical Studies, Darth Reid, and Redistribution
> Percy,
>
> As far as I know, IGRP and RIPV1 don't support tags.Pls correct me if I
am
> wrong
>
> Harish
>
>
>
>
>
> "Perminder
> Grewal" To:
Mark.Snow@newcome.com, ccielab@groupstudy.com
> <percy_gunner@hot cc:
> mail.com> Subject: Re: CCIE
Practical Studies, Darth Reid, and Redistribution
> Sent by:
> nobody@groupstudy
> .com
>
>
> 07/25/2002 09:56
> AM
> Please respond to
> "Perminder
> Grewal"
>
>
>
>
>
>
> Mark
>
> Don't worry too much about the lab. I did it this week and it has too
many
> mistakes, infact it is the worst lab I have ever done.
>
> Concentrate on the routing issues as feel this is where you seem to be
weak
>
> on, judging by your mail.
>
> On this lab I a tagged all the routes from the igrp & rip domain into the
> OSPF domain so those E2 extarnal routes will be asociated a tag no.
>
>
> Do sh ip ospf databse
>
>
> I use tag 11 from IGRP to OSPF on router 1 and tag 33 from rip to ospf on
> router 3.
>
> So when you redistrbute ospf back into IGRP and RIP use a route-map to
deny
>
> those tagged routes back in there respective routing domain.
>
> I feel tags is nice and easy, however for rip into igrp or vice versa you
> cannt use tags and will have to define an access-list and then use
> distribute-list.
>
> Have a look at doyles vol 1 he has some good examples. I've pasted an
> example below from darth reid.
>
> R1
>
> router ospf 1
> router-id 133.10.1.1
> redistribute igrp 1 subnets tag 22
>
>
> router igrp 1
> redistribute ospf 1 route-map ospf_2_igrp
>
> route-map ospf_2_igrp deny 10
> match tag 22
>
> route-map ospf_2_igrp permit 20
> set metric 1000 100 255 1 1500
>
>
> R3
>
>
> router ospf 1
> router-id 133.10.3.3
> redistribute rip subnets tag 33
>
>
> router rip
> redistribute ospf 1 route-map ospf_2_rip
>
>
> route-map ospf_2_rip deny 10
> match tag 33
> !
> route-map ospf_2_rip permit 20
> set metric 2
>
>
>
>
> Percy
>
>
> >From: "Snow, Mark" <Mark.Snow@newcome.com>
> >Reply-To: "Snow, Mark" <Mark.Snow@newcome.com>
> >To: ccielab@groupstudy.com
> >Subject: CCIE Practical Studies, Darth Reid, and Redistribution
> >Date: Thu, 25 Jul 2002 11:31:00 -0400
> >
> >All -
> >
> >I am having difficulties with Section V of the Lab Practice exam "Darth
> >Reid" in Solie's book, CCIE Practical Studies Volume 1.
> >I have completed the Lab, and for the most part gotten all the parts to
> >work, and have downloaded the answer PDFs from the CiscoPress web site.
> >
> >I really do not agree with some of the solutions that they give for this
> >specific lab, and was wondering if anyone had any insight (maybe someone
> >who
> >has taken this practice lab) as to why they answer the way they do.
> >Also does anyone have any really good ref material (links) for
> >redistribution?
> >
> >Specifically, the answer PDF has most of the routing protocols ALL
> >redistributing into each other, (OSPF into IGRP, and IGRP into OSPF,
OSPF
> >into EIGRP, and EIGRP into OSPF) (even OSPF into RIP on router R3 when
> the
> >lab specifically states NOT to advertise Lab routes onto the backbone -
so
> >there is no need for this).
> >I am also getting a lot of routing loops due to this and right now I am
> >clueless.
> >
> > > Mark Snow
This archive was generated by hypermail 2.1.4 : Sat Sep 07 2002 - 19:36:44 GMT-3