From: Howard C. Berkowitz (hcb@gettcomm.com)
Date: Sun Jun 29 2003 - 00:17:47 GMT-3
At 11:05 AM +0800 6/29/03, Punchi-san wrote:
>Hi Howard,
>
>If OSPF is redistributed to EIGRP, can I say redistribution just import OSPF
>routes into the EIGRP database. Those imported routes will be marked and
>WILL NOT install in the local router regardless of the AD ?
You're making the assumption that all EIGRP routes have the same AD.
Most are 95, some are 5, and some are 170.
At the CCIE level, you need to understand redistribution has the
limits it does. There is a very good reason for what you are seeing.
The hint I gave earlier: it's happening for the same reason ISIS and
OSPF are designed to prefer intra-area over inter-area over external
regardless of metric.
Why do you think these clues are related?
What could go wrong if an OSPF learned route were reported by EIGRP,
and OSPF went down? What if RIP imported routes from EIGRP?
Why don't iBGP routes get reannounced to other iBGP speakers in the
same AS (ignoring special cases)?
I'm hoping I can help you see the underlying general principles
rather than just trying to memorize protocol A does this with
protocol B.
>
>regards,
>alec
>----- Original Message -----
>From: "Howard C. Berkowitz" <hcb@gettcomm.com>
>To: <ccielab@groupstudy.com>
>Sent: Sunday, June 29, 2003 3:18 AM
>Subject: Re: protocol redistribution and route installation
>
>
>> At 12:17 AM +0800 6/29/03, Punchi-san wrote:
>> >Hi group,
>> >
>> >Just want to clarify the concept of protocol redistribution :
>> >
>> >R1 has both OSPF and EIGRP running and a route is originally learned from
>> >OSPF. If I redistribute the route from OSPF to EIGRP, why the OSPF route
>> >still get installed into the routing table. Isn't that the default
>admin.
>> >distance of EIGRP less than OSPF ? The route did install in the EIGRP
>> >topoloy database. Any hints appreciated.
>> >
>> >thanks
>> >punchi-san
>> >
>>
>> Some hints: think about why OSPF and ISIS install intra-area before
>> inter-area before external.
>>
>> Does EIGRP have more than one AD, as does IGRP?
>>
>> Why would it be important which protocol originally learned the
>> route? What could go wrong if other protocols seemed authoritative
>> for the same route learned by redistribution?
>>
>> While it's not the reason for this specific behavior, consider the
>> purpose of split horizon. That should give you insight.
>>
>>
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