03-09-2012 12:20 AM - edited 03-05-2019 06:47 AM
Hi Expert
in OSPF does the advertisement in point-2-point Link from one side as /32 and from other side as /30 affect the ospf work
thanks
03-09-2012 03:51 AM
Ibrahim,
The advertisement will work fine and wouldn't affect anything that I could see. The /32 would be preferred though if someone were trying to go to the address in the /30 block:
192.168.1.1/32 via s0/0
192.168.1.0/30 via s0/1
A user would go to the first path if they wanted to get to 192.168.1.1 instead of routing the way that you may have intended.
John
03-09-2012 04:15 AM
Hi John
Pls Have a look to below topology its Clear
R1----------- ----------R2
R1 F0/0 :1.1.1.1 255.255.255.252
R2 F0/0: 1.1.1.2 255.255.255.252
R1
OSPF 1
net 1.1.1.1 0.0.0.0 are 2
R2
OSPF 1
net 1.1.1.1 0.0.0.2 are 2
03-09-2012 04:47 AM
Ibrahim,
The mask under R2 would be incorrect and would need to be 0.0.0.3 (255-252 = 3), but overall I still get adjacencies with a configuration like this:
R1:
interface FastEthernet0/0
ip address 1.1.1.1 255.255.255.252
duplex auto
speed auto
router ospf 1
router-id 1.1.1.1
log-adjacency-changes
network 1.1.1.1 0.0.0.0 area 0
Neighbor ID Pri State Dead Time Address Interface
1.1.1.2 1 FULL/DR 00:00:39 1.1.1.2 FastEthernet0/0
R2:
interface FastEthernet0/0
ip address 1.1.1.2 255.255.255.252
duplex auto
speed auto
router ospf 1
router-id 1.1.1.2
log-adjacency-changes
network 1.1.1.0 0.0.0.3 area 0
Neighbor ID Pri State Dead Time Address Interface
1.1.1.1 1 FULL/DR 00:00:36 1.1.1.1 FastEthernet0/0
HTH,
John
Please rate...
03-09-2012 07:47 AM
Hi John
Even with the Below configuration , I Have Adjacency ,so how the mask is incorrect or even doesn't match on side while the do have Adjacency Pls Clarify
thanks
03-09-2012 07:53 AM
Your wildcard mask doesn't pair....are you sure you have it at 0.0.0.2 and not 0.0.0.3? Your mask with 0.0.0.2 would effectively translate to 255.255.255.253 which isn't valid. I'm assuming you just had a typo above?
Otherwise, you're basically say that 1.1.1.1/32 is in the range of the 1.1.1.0/30 (1.1.1.1-1.1.1.2 useable), so that's why you would have an adjacency. The masks don't have to match, but the addresses that are doing the neighborship need to fall into the same subnet.
Thanks for the rating!
03-09-2012 08:47 AM
Guys sorry , Mistypo the wild card is 0.0.0.3 not 0.0.0.2
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