RE: Host specific OSPF routes in table with /24 advertisement

From: Roberts, Larry (Larry.Roberts@xxxxxxxxxxxx)
Date: Wed Jun 12 2002 - 01:11:36 GMT-3


   
Loopbacks are automatically host routes within OSPF.

Under the loopback config add:

Ip ospf network point-to-point and that will make it become a /24.

I don't know why the second one is in there ( and pointing to the TokenRing
inteface..but Im sure someone does :) )
I suspect its because it's a point-to-multipoint interface though
Thanks

Larry

-----Original Message-----
From: gary braver [mailto:gbraver@attbi.com]
Sent: Tuesday, June 11, 2002 10:46 PM
To: Ccielab (E-mail)
Subject: Host specific OSPF routes in table with /24 advertisement

Stumped (and hopefully not a stupid question)

A quick scan of the R1 config will show all interfaces defined and
advertised with /24 bit mask. Yet the show IP route on R2 - has some ospf
entries with 32 bit masks

Why?

Partial Config on router R1 as follows:

interface Loopback0
 ip address 135.5.2.2 255.255.255.0
!
interface Serial0.1 multipoint
 ip address 135.5.34.2 255.255.255.0
 ip ospf network point-to-multipoint
 frame-relay map ip 135.5.34.3 103 broadcast
 frame-relay map ip 135.5.34.4 106 broadcast
!
interface Serial0.2 point-to-point
 ip address 135.5.42.2 255.255.255.0
 frame-relay interface-dlci 101
!
interface TokenRing0
 ip address 135.5.100.2 255.255.255.0
 ring-speed 16
!
router ospf 1
 log-adjacency-changes
 network 135.5.2.0 0.0.0.255 area 0
 network 135.5.34.0 0.0.0.255 area 0
 network 135.5.42.0 0.0.0.255 area 0
 network 135.5.100.0 0.0.0.255 area 0

R2 routing table
Gateway of last resort is not set

     135.5.0.0/16 is variably subnetted, 5 subnets, 2 masks
O 135.5.2.2/32 [110/7] via 135.5.100.2, 00:20:31, TokenRing0
C 135.5.8.0/24 is directly connected, Loopback0
O 135.5.34.2/32 [110/6] via 135.5.100.2, 00:20:31, TokenRing0
C 135.5.44.0/24 is directly connected, Ethernet0
C 135.5.100.0/24 is directly connected, TokenRing0

why are the ospf routes no to the /24 network?

r2 Routing statements
all interfaces /24 mask
router ospf 1
 network 135.5.100.0 0.0.0.255 area 0



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