From: Scott Morris (swm@emanon.com)
Date: Sun Apr 11 2004 - 10:29:55 GMT-3
You need to understand the behavior of the "network" command with IGP
protocols (BGP is different, in a lot of things!).
The network command does not specifically say which networks to advertise.
Instead, it indicates to the router which networks will participate in the
routing protocol. If the IP address of an interface falls within that
range, then it is 'tagged' as participating in the routing protocol. THEN
the actual network that the interface has will be brought in.
For example, if you have:
E0/0 = 10.0.0.1/24
S0/0 = 10.0.1.1/24
S0/1 = 10.0.2.1/24
E1/0 = 10.0.3.1/24
You can say:
Network 10.0.0.1 0.0.0.0 area 0 and this will only match the e0/0
Network 10.0.0.0 0.0.0.255 area 0 and only e0/0 will fall within that range
Network 10.0.0.0 0.0.0.3 area 0 and still only e0/0 will fall within that
range
Network 10.0.0.0 0.0.1.255 area 0 and both e0/0 and s0/0 will fall in here
Network 10.0.0.0 0.0.3.255 area 0 and all four interfaces will participate
in ospf
Network 0.0.0.0 255.255.255.255 area 0 and every single interface on the
router will participate in ospf
There are many ways to do it, but the only thing you are indicating to the
router is which interfaces participate in the routing protocol. The
networks advertised comes as a later step within ospf.
HTH,
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, CISSP,
JNCIS, et al.
IPExpert CCIE Program Manager
IPExpert Sr. Technical Instructor
swm@emanon.com/smorris@ipexpert.net
http://www.ipexpert.net
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Allan Wells
Sent: Sunday, April 11, 2004 5:34 AM
To: ccielab@groupstudy.com
Subject: advertise ospf as 192.168.1.1 /29 0.0.0.0 area 0 and not 0.0.0.7
Hi,
I have been doing some labs and looking at all the solutions.
Why is it some labs setup OSPF to use wildcard mask 0.0.0.0 with say /29
multipoint hub and spoke network
As apposed to to using 0.0.0.7 mask also I tried this config with eigrp and
theirs no problem their either what is the better way and why.
I always was under the impression we need to advertise the mask of the
network in the above example 0.0.0.7 obviously not.
This archive was generated by hypermail 2.1.4 : Mon May 03 2004 - 19:48:46 GMT-3