From: Scott Morris (smorris@xxxxxxxxxxxxxx)
Date: Wed Aug 08 2001 - 20:19:38 GMT-3
Ya know... To the tune of The Beatles' Yellow Submarine...
We all live in a Cisco Router pod... A Cisco Router pod... A Cisco Router
pod...
(Ok, I'll go back quietly to the white noise of my routers) ;)
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Chuck Church
Sent: Wednesday, August 08, 2001 5:58 PM
To: 'ccielab@groupstudy.com'
Subject: RE: Two areas don't make an ABR? How about area 0 only on
loopbac k?
You live in a pod? ;)
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Michael Snyder
Sent: Wednesday, August 08, 2001 9:58 AM
To: ccielab@groupstudy.com; Scott Morris
Subject: Re: Two areas don't make an ABR? How about area 0 only on
loopback?
Ok.
Try this one. I do this all the time in my pod.
I setup an OSPF router, with area 0 only on the loopback address. Why? well
on a head end, that is a single point of failure anyway, placing just one
interface in area zero allows all the other areas and interfaces on that
router to be very flexible. Pick a new area per subinterface per branch
office.
Think midsized company with only one core router and branch offices hanging
off of it.
If I put area 0 only the loopback,
Is this backbone router? I say yes.
Is this ASBR router? Could be if I'm also running another protocol.
Is this a ABR? About about if I only have one branch office? Is it still a
ABR?
----- Original Message -----
From: "Scott Morris" <smorris@mentortech.com>
To: "'Chuck Church'" <cchurch@MAGNACOM.com>; "'Chuck Larrieu'"
<chuck@cl.cncdsl.com>; <ccielab@groupstudy.com>
Sent: Wednesday, August 08, 2001 6:49 AM
Subject: RE: Two areas don't make an ABR?
> After reading a bunch of responses here, I'll belabor the obvious by
> pointing out that we need to look at the entirety of the commands. :)
>
> Try putting them in a router EXACTLY as they are listed right there.
> The masks on the network statements overlap for one, but also don't
indicate
> what's on the interface...
>
> If you enter answer C, you get:
> 3620-3(config-router)#network 10.0.0.1 0.0.0.0 area 0.0.0.0
> 3620-3(config-router)#network 192.168.1.1 0.0.255.255 area 0.0.0.1
> 3620-3(config-router)#network 192.168.0.1 0.0.0.0 area 0.0.0.0
> 3620-3(config-router)#
> % OSPF: "network 192.168.0.1 0.0.0.0 area 0.0.0.0" is ignored. It is a
> subset of a previous entry.
>
> So, YES, it makes it "sorta" an ABR since you have two areas. But it
treats
> BOTH ethernets (your REAL networks) as being part of the same area. So
for
> all intents and purposes in the real world, you are not an ABR!!!
>
> Never overlook the details. The small things will kill ya!
>
> Scott
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> Chuck Church
> Sent: Wednesday, August 08, 2001 12:18 AM
> To: 'Chuck Larrieu'; ccielab@groupstudy.com
> Subject: RE: Two areas don't make an ABR?
>
>
> What order are they evaluated in then? I was assuming top down, so the
> first statement would put the loopback interface into area 0. The second
> statement would match both other interfaces, putting them in area 1.
>
> Chuck
>
> -----Original Message-----
> From: Chuck Larrieu [mailto:chuck@cl.cncdsl.com]
> Sent: Tuesday, August 07, 2001 11:11 PM
> To: Chuck Church; ccielab@groupstudy.com
> Subject: RE: Two areas don't make an ABR?
>
>
> the interfaces are placed into areas based on the order of the network
> statements. once a match is made ( just like access-lists ) the processing
> stops.
>
> answer C 192.168.1.1 0.0.255.255 area 0.0.0.1 places both interfaces into
> area 1. processing stops. nothing ends up in area 0. therefor the router
is
> not an ABR. QED
>
> Chuck
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> Chuck Church
> Sent: Tuesday, August 07, 2001 7:21 PM
> To: 'ccielab@groupstudy.com'
> Subject: Two areas don't make an ABR?
>
>
> Gang,
>
> Got this email today from Certification Zone. I'm not quite sure I
> agree with the answer. Why doesn't answer 'C' meet the requirement?
>
> Chuck
>
> P.S. I don't have a Certification Zone subscription, otherwise I'd go read
> Howard's explanation!
>
>
> 7) This Week's CCIE Challenge Question
> ==============================================
> Which OSPF configuration fragment will cause abr1 to function as an
> area border router?
>
> hostname abr1
> int loop0
> ip addr 10.0.0.1 255.255.255.248
> int e0
> ip addr 192.168.0.1 255.255.255.0
> int e1
> ip addr 192.168.1.1 255.255.255.0
>
> a) router ospf 1
> network 192.168.0.0 0.0.0.0 area 0.0.0.0
> network 192.168.1.0 0.0.0.0 area 0.0.0.1
>
> b) router ospf 1
> network 192.168.1.1 0.0.255.255 area 0.0.0.1
> network 192.168.0.1 0.0.0.0 area 0.0.0.0
>
> c) router ospf 1
> network 10.0.0.1 0.0.0.0 area 0.0.0.0
> network 192.168.1.1 0.0.255.255 area 0.0.0.1
> network 192.168.0.1 0.0.0.0 area 0.0.0.0
>
> d) router ospf 1
> network 10.0.0.1 0.0.0.0 area 0.0.0.0
> network 192.168.1.1 0.0.0.0 area 0.0.0.1
> network 192.168.0.1 0.0.0.0 area 0.0.0.0
>
>
> The answer to this week's question can be found at:
> http://www.CertificationZone.com/QOW/1/ES/ccie-a.html
>
>
> Chuck Church
> CCNP, CCDP, MCNE, MCSE
> Sr. Network Engineer
> Magnacom Technologies
> 140 N. Rt. 303
>
> Valley Cottage, NY 10989
> 845-267-4000 x218
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