From: Lupi, Guy (Guy.Lupi@xxxxxxxxxxxxx)
Date: Sat Jun 29 2002 - 19:12:43 GMT-3
Actually, if the interface address is 199.199.199.1/24, and you use a
wildcard mask of 0.0.0.255, what interfaces is the router going to send
hello's out of, since you can't assign an interface an IP within a range
that is already on another interface?
Your argument would only stand if the interface address was
199.199.199.1/30, and he used 0.0.0.255 as his wildcard, because in that
scenario there could possibly be interfaces that belong to subnets within
the 199.199.199.0/24 that should not participate in OSPF, such as
199.199.199.4/30.
Guy
-----Original Message-----
From: Krake, Kris
To: Lupi, Guy; 'Ahmed Al-Ghawas'; ccielab@groupstudy.com
Sent: 6/29/2002 5:12 PM
Subject: RE: OSPF wildcard bits
Consider this....
Do you want to be sending hellos out interfaces that might not be part
of
the OSPF process *looking* for a peer. I'd say that was a waste of
resources.
Much like being specific in your other IGPs as to which interfaces a
protocol is advertising on (like RIP and IGRP) with passive-interface
default, it is good practice to limit the hellos to the interfaces that
are
actually being used by OSPF. From the scenario of the lab it is MORE
correct.
JMHO,
Kris
-----Original Message-----
From: Lupi, Guy [mailto:Guy.Lupi@eurekaggn.com]
Sent: Saturday, June 29, 2002 4:25 PM
To: 'Ahmed Al-Ghawas'; ccielab@groupstudy.com
Subject: RE: OSPF wildcard bits
I don't know that you should be too concerned about how they want you to
do
it because I don't think they have a "preferred method", but definitely
understand how the command works. I don't think they would be overly
concerned that you added in the whole range on the lab, unless they told
you
to be as specific as possible with your network statements. I would
just
pick one method and stay with it. In practice, in order to avoid
problems
when people enter the wrong network statement wildcard mask, I prefer to
use
"passive-interface default". This forces each interface on which you
want
to run OSPF to be specifically stated in the configuration.
Guy
~-----Original Message-----
~From: Ahmed Al-Ghawas [mailto:ghawas@batelco.com.bh]
~Sent: Saturday, June 29, 2002 3:37 PM
~To: ccielab@groupstudy.com
~Subject: OSPF wildcard bits
~
~
~Guys,
~
~I am really getting confused!
~
~From what I understood from "CCIE Practical Studies" book that
~when using the
~network command, that you ought to be precise in the extent
~that you would add
~the interface ip address and not advertise the whole subnet mask!
~
~For example:
~
~R1
~S0:10.1.128.1/24
~|
~|
~S0:10.1.128.2/24
~R2
~S1:10.1.80.1/24
~|
~|
~S1:10.1.80.3/24
~R3
~
~R1 config:
~router ospf 2001
~network 10.1.128.1 0.0.0.0 area x (and not; network 10.1.128.0
~0.0.0.255 area
~x!!)
~
~R2 config:
~router ospf 2001
~network 10.1.128.2 0.0.0.0 area x (and not; network 10.1.128.0
~0.0.0.255 area
~x!!)
~network 10.1.80.1 0.0.0.0 area x (and not; network 10.1.80.0
~0.0.0.255 area
~x!!)
~
~R3 config:
~router ospf 2001
~network 10.1.80.3 0.0.0.0 area x (and not; network 10.1.80.0
~0.0.0.255 area
~x!!)
~
~I really need to stick to one concept and understand why this
~book doest it
~differently then the other and avoid loosing marks for such
~stupid thing in
~the real lab!!
~
~Any input is much appreciated
~
~Ahmed
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