From: James Matrisciano (jmatrisciano@kenttech.com)
Date: Fri Dec 09 2005 - 19:48:05 GMT-3
With the following
Ospf router 1
Net 1.1.1.1 0.0.0.0 area 0
Net 3.3.3.1 0.0.0.0 area 0
Int s0/0
Ip add 1.1.1.1 255.255.255.0
Ip ospf net broadcast
Int s0/0.3 m
Ip add 3.3.3.1 255.255.255.0
Ip ospf net point-to-multipoint
You area connected to router 2 and router 3 via Frame all DLCI's are
mapped
Once your network has converged, you will get statements in your routing
table with a /32 of the interface that router is connected to. This
will break the restriction of advertise the interface with its configure
mask.
With this set up (and forgive me, my lab is not on line, so I can not
copy paste my sh ip route statements)
In router 3 that is connected to router 1 with
S2/0
Ip add 3.3.3.3 255.255.255.0
ip ospf net point-to-multipoint
Router ospf 1
Net 3.3.3.3 0.0.0.0 area 0
Sh ip route
1.0.0.0
O 1.1.1.0 (these are the routes to get to R2
3.0.0.0/8
O 3.3.3.1/32
C 3.3.0/24
What you want to look for is that if you have a restriction saying
"advertise as configured" the 3.3.3.1 interface is configured as a /24,
not a /32
As well, in router 2 that is connected the same way except with the ip
ospf network broadcast command on the interface, the routing table
shows:
3.0.0.0/32
In its routing table, this would be a break in the restriction.
Using ip ospf network point-to-point fixes this problem, but only if you
are allowed to have point-to-point neighbor relationships
-----Original Message-----
From: Schulz, Dave [mailto:DSchulz@dpsciences.com]
Sent: Friday, December 09, 2005 5:33 PM
To: James Matrisciano; Melwani, Manoj J; Kim Judy;
ccielab@groupstudy.com
Subject: RE: Wildcard issue
James -
Can you please expound on the advertisement issue that you state. I
didn't think that the network command under ospf had anything to do with
how the interface was advertised. I thought that this only determined
which interfaces were included in the ospf process. I do agree that the
ospf network command does affect the advertisement.
Dave Schulz
Email: dschulz@dpsciences.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
James Matrisciano
Sent: Friday, December 09, 2005 5:13 PM
To: Melwani, Manoj J; Kim Judy; ccielab@groupstudy.com
Subject: RE: Wildcard issue
You need to watch out for your restrictions on the 0.0.0.0 mask. If you
have a restriction that all interfaces must be advertised with their
original mask, make sure you do not use the 0.0.0.0 unless you are
allowed to use the ip ospf network point-to-point command under the
interface you are conneting with. Again, this will fall under the
restrictions of how you can have your ospf neighbors talk to each other.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Melwani, Manoj J
Sent: Friday, December 09, 2005 4:45 PM
To: Kim Judy; ccielab@groupstudy.com
Subject: RE: Wildcard issue
The best practice is to use the second method. By using 0.0.0.0 wildcard
you are saying that I want to run OSPF routing process just on that
particular interface unless if you have a whole range of interface that
you want to use on the same line then you might want to use the first
method.
Yes Its a good idea to use router-id under the routing process. Use
Loopback 0 as your router id's.
Thanks,
Manoj.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Kim Judy
Sent: Friday, December 09, 2005 4:15 PM
To: ccielab@groupstudy.com
Subject: Wildcard issue
hi group,
I have a query that if a interface has an Ip address 172.16.12.1/25 What
wild card bits should I use under the IGP process ?
router ospf 1
net 172.16.12.1 0.0.0.127 or
net 172.16.12.1 0.0.0.0
which is the best way ? What does Cisco expect from us ?
If not specified should I use a "router-id" under each IGP running on a
router ?
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