From: Scott Morris (smorris@xxxxxxxxxxxxxx)
Date: Wed Aug 08 2001 - 11:22:19 GMT-3
Go figure, huh? :) I don't know as I'd classify that as idiot-proofing or
not.
I'd be interested in a "show ip ospf interface" output to see what interface
is in what area with conflicting statements there. Has it become "best
match" criteria?
If nothing else, on an exam, always remember it's the BEST answer... And
usually with scenarios like this, it will follow Cisco's "best practices"
for net design/implementation. And... most exams are probably still 11.x
code-related.
*shrug*
:)
Scott
-----Original Message-----
From: Chuck Larrieu [mailto:chuck@cl.cncdsl.com]
Sent: Wednesday, August 08, 2001 10:10 AM
To: smorris@mentortech.com; ccielab@groupstudy.com
Subject: RE: Two areas don't make an ABR?
Scott - check my results on a 12.x IOS. apparently what was once true -
that statements are processed in order entered - has changed
MANAGER(config)#
MANAGER(config)#
MANAGER(config)#
MANAGER(config)#router ospf 100
MANAGER(config-router)#network 10.0.0.1 0.0.0.0 area 0.0.0.0
MANAGER(config-router)#network 192.167.0.0 0.0.255.255 area 0.0.0.1
MANAGER(config-router)#network 192.167.0.1 0.0.0.0 area 0.0.0.0
MANAGER(config-router)#^Z
MANAGER#sh run
Building configuration...
Current configuration:
!
!
router ospf 100
network 10.0.0.1 0.0.0.0 area 0.0.0.0
network 192.167.0.1 0.0.0.0 area 0.0.0.0
network 192.167.0.0 0.0.255.255 area 0.0.0.1
apparently this is part of the idiot proofing that Cisco has been
introducing in 12.x
us old dogs who learned things with real IOS versions have some new tricks
to learn!
Chuck
-----Original Message-----
From: Scott Morris [mailto:smorris@mentortech.com]
Sent: Wednesday, August 08, 2001 4:50 AM
To: 'Chuck Church'; 'Chuck Larrieu'; ccielab@groupstudy.com
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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