From: Ben-Shalom, Omer (omer.ben-shalom@xxxxxxxxx)
Date: Wed Nov 07 2001 - 16:59:32 GMT-3
The OSPF network statement really has nothing to do with networks it is an
access list (and that is why it uses the mask the way it does) to filter the
interfaces to take part in OSPF, you COULD use the right network mask for
the interfaces or not, that is really a style issue.
A while back I asked the same thing stating that I personally prefer the
network mask to a host mask but later was convinced by a number of good
people that unless you have a big router with many interfaces using the host
mask is cleaner and less prone to mistakes and surprises so I am now using a
host mask.
Again - both will work and this is really a style issue nothing more.
Omer.
-----Original Message-----
From: lgao [mailto:lgao@cisco.com]
Sent: Wed, November 07, 2001 7:57 PM
To: Courtney Foster
Cc: Dennis #6; CCIE Groupstudy
Subject: Re: CCBootCamp 5 OSPF over frame question
I don't think it is the best practice to advertise a host mask, it looks
like a lazy thing that dont' want to figure out what the true mask is.
Courtney Foster wrote:
> It is a host specific mask....because you don't have broadcast...you are
> telling OSPF that this host is Area 10...At least that's what I think
>
> -----Original Message-----
> From: Dennis #6 [mailto:vacant@home.com]
> Sent: Wednesday, November 07, 2001 12:04 PM
> To: CCIE Groupstudy
> Subject: CCBootCamp 5 OSPF over frame question
>
> I noticed on the CCBootCamp lab 5 solution that the wildcard mask on
> each router for the point-to-multipoint frame connections is 0.0.0.0
> (see below). Is there a good reason for using this mask as opposed to
> 0.0.0.255 (it's a /24 subnet)? When is it best to use 0.0.0.0 versus
> 0.0.0.255. I thought it was normal to use the inverse mask that
> corresponds to the subnet mask on that interface. What am I missing?
>
> router ospf 1
> redistribute igrp 1 metric 20 metric-type 1 subnets
> network 172.168.100.5 0.0.0.0 area 10 !point to multipoint frame
> connection network 137.20.20.0 0.0.0.255 area 0 area 10 virtual-link
> 172.168.30.97 area 10 virtual-link 172.168.100.6
>
> Thanks,
>
> Dennis #6
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