From: Steven Hodgson (steven.hodgson@inxi.com)
Date: Wed Dec 19 2007 - 13:59:23 ART
I'm not an expert, but the mask just specifies which interfaces you want
to participate in OSPF. Using the 0.0.0.0 masks makes it specific to
just one IP address. If you used the 255.255.255.255 address it would
enable OSPF on all interfaces. It doesn't have anything to do with
which networks get advertised. That's a product of the subnet mask on
the interface.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Gregory Gombas
Sent: Wednesday, December 19, 2007 9:54 AM
To: ALee@cccis.com
Cc: ccielab@groupstudy.com
Subject: Re: OSPF network statement
Since the interface has a /24 mask the two commands do essentially the
same thing which is enable OSPF on the interface, assign it to an
area, and advertise that network.
You're probably better off using the 0.0.0.0 mask because it is more
restrictive and you have greater control over which interface you are
enabling OSPF on.
You can also use the interface level command to enable OSPF on the one
interface.
I vaguely remember a corner case scenario where the different wildcard
mask lead to difference in behavior but don't remember the details.
Maybe someone can chime in here?
Regards,
Gregory Gombas
CCIE #19649
On Dec 19, 2007 9:56 AM, <ALee@cccis.com> wrote:
> Can anyone tell me the difference of the OSPF network statement below?
> Such as the difference showing in OSPF database, routing table, etc.
Which
> network statement is preferred? Thanks.
>
>
> interface Vlan20
> ip address 172.20.20.1 255.255.255.0
>
> router ospf 10
> network 172.20.20.1 0.0.0.0 area 0.0.0.0
>
> V.S.
>
> router ospf 10
> network 172.20.20.0 0.0.0.255 area 0.0.0.0
>
>
>
> Arthur Lee
>
>
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