From: Brian Hescock (bhescock@xxxxxxxxx)
Date: Thu Dec 28 2000 - 18:19:21 GMT-3
The wildcard bits don't waste any ip addresses at all, all it merely does
is turn on ospf on an interface. ospf takes the network mask from the
interface, not your network statement. The only way to save address space
is to use the most efficient mask on the interface that meets the
requirements.
In summary, it was a bad question, the requirement wasn't really clear
given the information we had.
Brian
On Thu, 28 Dec 2000, Eric Lemmons wrote:
> As I understand the requirement asked for, "What is the correct
> command to insert these networks into the OSPF process in the most
> efficient manner? By that, I mean conserving the maximum amount of
> IP addresses", the correct answer would be the host route answer.
> Meaning, Julie Ann's answer. The requirement was not concerned with
> minimizing the number of router config statements, but "conserving
> the maximum amount of IP addresses". With the 0.0.0.0 mask, this
> leaves all of the other IP addresses available between the 20,28,36,
> and 44 subnets, instead of "swallowing" them in the mask. For
> example, you couldn't put an IP address like 192.168.21.x into a
> different area, because it has been put into area 0 with the larger
> statement that Earl suggests, "Network 192.168.0.0 0.0.63.255 area
> 0".
> I know this is all pretty picky :).
> But I think the individual 0.0.0.0 masks fits the requirements the
> best.
>
> --- Brian Hescock <bhescock@cisco.com> wrote:
> > Earl's answer is probably the one you're looking for if we
> > understand your
> > requirement correctly. But if you aren't told you must only have
> > one
> > network entry, I agree with the other person that said to use the
> > ip
> > address off of the interface and 0.0.0.0 wildcard bits, as in:
> >
> > network 172.168.1.1 0.0.0.0 area 0
> >
> > There's less chance for error and it's obvious if the proctor
> > changes it
> > because the ip address will always be the ip address from the
> > interface
> > and the wildcard bits are always 0.0.0.0. This is also a
> > recommended
> > way to do it in a production network *IF* you don't have a lot of
> > interfaces, it makes troubleshooting far easier.
> >
> > By the way, why such a huge network for the loopback, why not a /24
> > or a /30 or /32? It's going to be advertised as a /32 anyway if
> > you don't
> > change the ospf network type to something other than the default.
> >
> > Brian
> >
> > On Thu, 28 Dec 2000, Earl Aboytes wrote:
> >
> > > I think this is the answer that you are looking for.
> > >
> > > Network 192.168.0.0 0.0.63.255 area 0
> > >
> > > This would put all networks 192.168.0.0 through 192.168.63.0 in
> > area 0
> > >
> > > Watch out that you don't have any other conflicts. To be
> > cautious I always
> > > make separate entries and make sure that my masks match my
> > wildcards.
> > >
> > > Earl Aboytes CCIE 6097
> > >
> > > PS. Sam@datastreet, if you read this post I want you to know that
> > I think
> > > that it's pretty cool how involved you are in this CCIE thing.
> > My dad can't
> > > even remember the meaning of the four letters C-C-I-E.
> > >
> > > -----Original Message-----
> > > From: Connary, Julie Ann [mailto:jconnary@cisco.com]
> > > Sent: Thursday, December 28, 2000 11:51 AM
> > > To: fwells12
> > > Cc: ccielab@groupstudy.com
> > > Subject: Re: OSPF network statement
> > >
> > > Since each loopback interface will be a host route, use 4 network
> > > statements like:
> > >
> > > network 192.168.20.2 0.0.0.0 area X
> > >
> > > Julie Ann
> > >
> > > At 11:17 AM 12/28/2000 -0800, fwells12 wrote:
> > > >I have the following IP addresses configured as loopback
> > interfaces on =
> > > >an OSPF router. What is the correct command to insert these
> > networks =
> > > >into the OSPF process in the most efficient manner? By that, I
> > mean =
> > > >conserving the maximum amount of IP addresses.
> > > >
> > > >interface Loopback0
> > > > ip address 192.168.20.2 255.255.248.0
> > > >!
> > > >interface Loopback1
> > > > ip address 192.168.28.2 255.255.248.0
> > > >!
> > > >interface Loopback2
> > > > ip address 192.168.36.2 255.255.248.0
> > > >!
> > > >interface Loopback3
> > > > ip address 192.168.44.2 255.255.248.0=20
> > > >
> > > >Cheers.
> > > >
> > > >
> > > >
> > > >
> > > >
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 08:26:12 GMT-3