From: Scott Morris (swm@emanon.com)
Date: Mon Jan 29 2007 - 15:26:06 ART
Heheheh... Now that's a good question! And the answer is "keep it simple".
If you are told to have a route look a certain way, and that's the only
thing that's mentioned, then I would probably just redistribute it as an E2
and change the cost (default = 20).
But if you get a scenario where you're given two different sets of things to
"look like" then you need to see whether you'll be treating them as E1s and
manipulating metrics along the path, or whether you simply do two different
redistributions (or route-map) to match certain routes and set certain
metrics bringing them in.
There's no answer that will work all the time, but it's good to be able to
see the options, and mentally be able to "trace" a route through your
network and ask yourself "if I redistribute over here, what will the route
look like over on the other side of my network?".
If you can answer that in your head, then you are definitely on the right
path!!!
HTH,
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE
#153, CISSP, et al.
CCSI/JNCI-M/JNCI-J
IPexpert VP - Curriculum Development
IPexpert Sr. Technical Instructor
smorris@ipexpert.com
http://www.ipexpert.com
-----Original Message-----
From: ManojCCIE [mailto:manojccie@gmail.com]
Sent: Monday, January 29, 2007 10:54 AM
To: 'Scott Morris'; 'Edouard Zorrilla'; ccielab@groupstudy.com
Cc: security@groupstudy.com
Subject: RE: OSPF External Types
So if you want a redistributed external route to have a certain metric at an
internal router, what's the best way to go about that? Would you
redistribute as an E1, and set the cost to make sure it and the added cost
to the internal router add up to the magic number(modified redistributed E1
cost + cost of path to internal router = total ospf cost metric)? Or would I
just let it in as an E2 and assign the cost I need?
I think either way would work, but I feel that if I use the first, something
may change the link characteristics and ruin the formula. On the other hand
is it right to let all routes come in at some weird(non-default) E2 cost
value?
Thanks in advance,
Manoj
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Scott Morris
Sent: Monday, January 29, 2007 7:44 AM
To: 'Edouard Zorrilla'; ccielab@groupstudy.com
Cc: security@groupstudy.com
Subject: RE: OSPF External Types
They look the same as far as a route goes, except like you note that the
cost increases on an E1. Otherwise, they have the same characteristics as
far as whether they're allowed in certain area types (or not), and how the
next-hop information is handled.
You'll see them in your routing table as O E1 or O E2 routes. :)
HTH,
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE
#153, CISSP, et al.
CCSI/JNCI-M/JNCI-J
IPexpert VP - Curriculum Development
IPexpert Sr. Technical Instructor
smorris@ipexpert.com
http://www.ipexpert.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Edouard Zorrilla
Sent: Monday, January 29, 2007 7:49 AM
To: ccielab@groupstudy.com
Cc: security@groupstudy.com
Subject: OSPF External Types
Hello There,
I would like to know the difference between E1 and E2 (default) external
types ? For instance I know that OE1 add the internal cost of each link it
crosses and OE2 does not. Let me know if there is something beyond this.
Also, how can I change the default behaviour, I mean what can I do so that I
see in my routing table a E1 instead a E2 ? Any exaple would be appreciate.
Regards
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