From: Brian Dennis (bdennis@internetworkexpert.com)
Date: Fri Apr 14 2006 - 11:38:54 GMT-3
Of course you can use all kinds of methods to have the "routing table"
prefer one route over another but that wasn't the question. The
question was basically asking if inter-area routes can be preferred to
intra-area routes. With PBR you are overriding the routing table but
not changing the route selection process within OSPF itself. The
problem I have with your answer is that people will now assume that they
can get PBR to have OSPF select inter-area routes over intra-area routes
which isn't true.
Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
bdennis@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 775-745-6404 (Outside the US and Canada)
-----Original Message-----
From: Aaron Pilcher [mailto:apilcher@itgcs.com]
Sent: Friday, April 14, 2006 4:54 AM
To: Brian Dennis; 'ZeroFlash'; 'Faryar Zabihi (fzabihi)'; 'James
Simons'; 'Cisco certification'
Subject: RE: OSPF route preferencing
I 110% agree, but you could force a single ospf router to route over an
inter-area route when the ospf process would naturally select an
intra-area
route. I mean, making "unnatural" stuff happen is what PBR is all
about.
-----Original Message-----
From: Brian Dennis [mailto:bdennis@internetworkexpert.com]
Sent: Thursday, April 13, 2006 11:37 PM
To: Aaron Pilcher; ZeroFlash; Faryar Zabihi (fzabihi); James Simons;
Cisco
certification
Subject: RE: OSPF route preferencing
To have inter-area routes preferred over intra-area routes, policy based
routing (PBR) will not work. PBR can not alter the route selection
process within OSPF itself. So this means that if the requirement is to
prefer inter-area over intra-area OSPF routes, PBR will not meet the
requirement.
HTH,
Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
bdennis@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 775-745-6404 (Outside the US and Canada)
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Aaron Pilcher
Sent: Thursday, April 13, 2006 7:45 PM
To: 'ZeroFlash'; 'Faryar Zabihi (fzabihi)'; 'James Simons'; 'Cisco
certification'
Subject: RE: OSPF route preferencing
To add to your points, PBR would also fit the bill.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
ZeroFlash
Sent: Thursday, April 13, 2006 9:27 PM
To: 'Faryar Zabihi (fzabihi)'; James Simons; Cisco certification
Subject: RE: OSPF route preferencing
Creating a tunnel would certainly help in learning routes from one area
to
another to influence route selection based on inter/intra area routes.
The
only with this is to be careful not to learn your tunnel routes through
the
tunnel or you'll get recursive routing and the tunnels will bounce.
I would also think about another type of tunnel, perhaps a virtual-link
here
might help.
Just some thoughts off the top o the head.
Later...
ZeroFlash
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Faryar Zabihi (fzabihi)
Sent: Thursday, April 13, 2006 10:20 PM
To: James Simons; Cisco certification
Subject: RE: OSPF route preferencing
As you might well know...AD will not work here. You might be able to
accomplish this through having another OSPF process but haven't tried.
You can also change routing protocol for those routes(but you probably
don't want that) Also if you want to get yourself into a mess read
this(I have and never implemented)
http://mirrors.isc.org/pub/www.watersprings.org/pub/id/draft-mirtorabi-o
spf-tunnel-adjacency-00.txt
I suggest you take a step back and see what the requirement really wants
you to do.
Faryar Zabihi
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
James Simons
Sent: Thursday, April 13, 2006 6:51 PM
To: Cisco certification
Subject: OSPF route preferencing
Hello all,
Another OSPF question for you all. OSPF always prefers intra-area
routes over inter-area routes, regardless of the route cost right? Is
there anyway to get a router to prefer an inter-area route? If there
are multiple methods, I would like to know as many of them as possible
since you never know what you will be allowed to do in the lab.
thanks,
Jimmy
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