From: ying chang (ying_c@xxxxxxxxxxx)
Date: Mon Apr 01 2002 - 00:59:08 GMT-3
Bill,
This make sense when split-horizon is disabled and see it in action in the
lab. Can this happen when split-horizon is enabled? I normally would take
your advice and use the filter to prevent route feedback, but like to know
if this is the only situation that can cause this problem.
Thanks,
Chang
>From: "Bill Hill" <bhill@sgdata.com>
>Reply-To: "Bill Hill" <bhill@sgdata.com>
>To: "ying chang" <ying_c@hotmail.com>, <ccielab@groupstudy.com>
>Subject: RE: routing loop in single redistribution point?
>Date: Sun, 31 Mar 2002 20:52:27 -0500
>
>Sure, try redistributing IGRP into OSPF and vice versa on a medium where
>split horizon is not enabed by default. An OSPF route learned by IGRP will
>be redistributed back into OSPF meaning that the route will now be favored
>via the IGRP router, hence causing a routing loop. Actualy in this case
>you will see the route appear in the table then the router will state that
>the route is possibly invalid, then will disappear completely and reappear.
>
>In any case, proper use of distribute-lists, route-maps, enabling split
>horizon will fix these issues. Key to remember is to be specific with your
>redistribution so that you don't run into this issue. It does help to see
>it in action though so try mocking it up in the lab.
>
>HTH
>-Bill
>#8882
>
>-----Original Message-----
>From: ying chang [mailto:ying_c@hotmail.com]
>Sent: Sunday, March 31, 2002 7:58 PM
>To: ccielab@groupstudy.com
>Subject: routing loop in single redistribution point?
>
>
>Hi all,
>
>In Solie's CCIE Pratical Studies errata for page 623, he took out the
>following statement from the 'Caution' box: "If there is only one
>redistribution point, inherent loop prevention whithin the routing protocol
>will be sufficient enough to prevent loops". I can see multiple
>redistributing points can cause routing loop as demonstrate in Doyle I's
>Route Filtering chapter, but have troubles to see how a routing loop can be
>fromed in a single redistribution point. Can someone give me an example of
>such case?
>
>Thanks,
>Chang
>
>
>
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