From: Reza Toghraee (reza@toghraee.com)
Date: Mon Oct 13 2008 - 13:13:43 ART
Yes I did, and also I saw that if you put "ip ospf cost 65535" on the
loopback and the transit link, the neighbor router will see the route with
metric of 131070.
Also I connected 3 routers together with OSPF, with interfaces having "ip
ospf cost 65535". In the last router I saw the loopback of 1st router with
metric of 196605 (3*65535)
Now the question is that the Metric field in LSA packet is 16 bits, how it
carries more than 16 bit (65535) ?????
-----Original Message-----
From: Richard L. Pickard [mailto:richardlpickard@hotmail.com]
Sent: Monday, October 13, 2008 7:54 PM
To: 'Reza Toghraee'
Subject: Re: OSPF Question, how to prefer inter area routes, over intra area
but if there is no other path your data will use that path.
This is why it is good to have real routers - you can mock up stuff like
this & see how it works.
R
----- Original Message -----
From: "Scott Morris" <smorris@internetworkexpert.com>
To: "'Reza Toghraee'" <reza@toghraee.com>
Cc: <ccielab@groupstudy.com>
Sent: Monday, October 13, 2008 9:18 AM
Subject: RE: OSPF Question, how to prefer inter area routes, over intra area
> Correct. You are setting your links cost (thus the router advertisements)
> to the maximum value which basically says "I'm here, but don't use me!"
>
> -----Original Message-----
> From: Reza Toghraee [mailto:reza@toghraee.com]
> Sent: Monday, October 13, 2008 8:01 AM
> To: 'Scott Morris'
> Cc: ccielab@groupstudy.com
> Subject: RE: OSPF Question, how to prefer inter area routes, over intra
> area
>
> Yes I manipulated, and changed the cost of other links to a higher value.
> But I didn't check the "sh ip ospf virt". Now I understand why it doesn't
> go
> on virtual link by default. BECAUSE the COST of VIRTUAL-LINKS is
> significantly higher.
>
> 1 more question : What does "ip ospf cost 65535" mean? Does it mean that
> NO
> TRAFFIC will pass the link even if this is the only operational link?
>
> Regards
> Reza
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Scott Morris
> Sent: Monday, October 13, 2008 3:52 PM
> To: 'Reza Toghraee'
> Cc: ccielab@groupstudy.com
> Subject: RE: OSPF Question, how to prefer inter area routes, over intra
> area
>
> Once you have your virtual link, you'll notice that the cost to the routes
> is significantly higher though. Have you tried manipulation in this
> sense?
> (sh ip ospf virtual-link)
>
> -----Original Message-----
> From: Reza Toghraee [mailto:reza@toghraee.com]
> Sent: Monday, October 13, 2008 6:40 AM
> To: smorris@internetworkexpert.com
> Cc: ccielab@groupstudy.com
> Subject: RE: OSPF Question, how to prefer inter area routes, over intra
> area
>
> It's a Lab scenario, I crated myself of course its amazing ;)
>
> I found this Method, and its working
>
> 1) R3 peers with R2 over a virtual link on Area23
> 2) R1 peers with R3 over a virtual link on Area13
> 3) R1 puts ospf cost 100 on its 64K link to R2.
>
> So R1 receives R2' Loopback interface over its 64K link and also from
> Virtual link from R3. Both as intra-area.
> By default it should prefer the virtual link, and if not we can use ip
> ospf
> cost to change metrics.
>
>
> -----Original Message-----
>
> You'll ALWAYS get intra-area over inter-area. That's the way the spec is
> written, and it just plain makes sense. :)
>
> Was it intentional to make the slowest path the "backbone" of your OSPF
> network?
>
> Scott
>
> -----Original Message-----
> 174.1.13.0/24
> _____ __________________________ _____
> | R1| | | | R2|
> |___|---| A R E A 0 |--------|___|
> | | This link is a 64K | |
> | |__________________________| |
> | ____|______
> __|__________ | |
> | | | |
> | AREA13 | _______| |
> | | 174.1.31.1 V13 | |
> | 10Mbps | | |
> |____________| | A R E A 23 |
> | | |
> __|__ |_________________| 10Mbps BW |
> | R3| | |
> |___|-------|___________________________________|
> 174.1.43.4 /24 V 43
>
>
>
> R2 is advertising it Looback in OSPF AREA 0 ,with network command.
> R1 will route through the AREA 0, on 64K Link to reach R2' Loopback 0.
>
> Question 1 : how to make R1, route through R3 on Area 13, and Area 23 to
> reach R2' Loopback ?
>
> What I tried :
> 1) I tried to use distance on the routes coming from R2, to change them to
> 130, but seems the OSPF first chooses the InterArea route over intra area,
> then applies the distance.
> 2) I used a distribution-list on R1 to filter the routes coming from R2.
> Its
> working but if the Link between R1,R3 is disconnected, then R1 cannot
> reach
> R2' Loopback
>
>
> Question 2: R2 Advertises its Loopback with Redistribution as E1.
>
> What I tried :
>
> 1) I tried to change the costs on 64K Link to very high. But I don't
> remember it worked or not.
>
>
> Waiting for your solutions.
> Reza Toghraee
>
>
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