From: Brian McGahan (brian@cyscoexpert.com)
Date: Wed Sep 11 2002 - 17:13:41 GMT-3
Based on the presented document, I can see why this is
confusing. Although this author states "The default behavior is to not
redistribute any routes from OSPF into BGP," this is not actually the
case. A "match" keyword is only necessary when redistributing external
OSPF routes of either LSA 5 or 7 into BGP. For all OSPF learned routes
to be candidate for redistribution into BGP, you would need the
statement:
Router bgp 1
redistribute ospf 1 match internal external 1 external 2 nssa-external
1 nssa-external 2
The RFC states one thing, Cisco implements a second thing, and
their documentation references third. Unfortunately, this is common
practice. The only difference between in theory and in practice is that
in theory, there is no difference.
Besides, why would you want to redistribute between BGP and IGP
anyways? :)
HTH
Brian McGahan, CCIE #8593
Director of Design and Implementation
brian@cyscoexpert.com
CyscoExpert Corporation
Internetwork Consulting & Training
http://www.cyscoexpert.com
Voice: 847.674.3392
Fax: 847.674.2625
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Jay Greenberg
> Sent: Wednesday, September 11, 2002 2:20 PM
> To: Peng Zheng
> Cc: ccielab@groupstudy.com
> Subject: Re: Redistribute OSPF to BGP
>
> I just did this in a lab, and on a router running IOS 12.0(21a), it
did
> not require the *match* keyword to perform redistribution from ospf to
> BGP.
>
> It seems really odd to me that they would have said that, however I
have
> a theory. The referenced RFC 1403 states that:
>
> The default MUST be to export no routes from OSPF into
> BGP. A single configuration parameter MUST permit all
> OSPF inter-area and intra-area routes to be exported
> into BGP.
>
> Theoretically, that could be misunderstood. Maybe the initial
> programmers thought that "the default must be" meant even when
> "redistribute ospf 1" is supplied.
>
> Can anyone try this on an old IOS version? Can anyone clear this up?
>
> On Wed, 2002-09-11 at 14:01, Peng Zheng wrote:
> > Hi,
> >
> > >From
> > http://www.cisco.com/warp/public/104/bgp-ospf-redis.html
> >
> > It said when you redistribute OSPF to BGP, you must
> > use match. But in CIM BGP, match is not used.
> >
> > I'm wondering if I should use it.
> >
> > Thank you for help.
> >
> >
> > Best Wishes,
> > Peng Zheng
> >
> > __________________________________________________
> > Yahoo! - We Remember
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