06-11-2007 07:51 AM - edited 03-03-2019 05:23 PM
Hello,
I have the following configured
fr_hub#sh run int s0/0.201
Building configuration...
Current configuration : 124 bytes
!
interface Serial0/0.201 point-to-point
ip address 202.2.2.1 255.255.255.252
frame-relay interface-dlci 201 IETF
fr_hub#sh run | b router ospf
router ospf 1
log-adjacency-changes
network 202.2.2.0 0.0.0.3 area 0
and on the spoke...
spoke1#sh run int s0/0.1
Building configuration...
Current configuration : 120 bytes
!
interface Serial0/0.1 point-to-point
ip address 202.2.2.2 255.255.255.0
frame-relay interface-dlci 101 IETF
spoke1#sh run | b router ospf
router ospf 1
log-adjacency-changes
network 202.2.2.0 0.0.0.3 area 0
Now of course these interfaces are type:
POINT TO POINT, but for some reason the hub is seeing this route....
fr_hub#sh ip route ospf
202.2.2.0/24 is variably subnetted, 2 subnets, 2 masks
O 202.2.2.0/24 [110/3570] via 202.2.2.2, 00:05:49, Serial0/0.201
So, the spoke is telling the HUB the /24 on the point to point link.
Why is the hub believing the spoke has more information about the point to point link that it has? or is the hub just learning the spoke's network lsa.
thanks,
Joe
06-11-2007 07:53 AM
Your spoke has an incorrect subnet mask so it will cover networks other than 202.2.2.1-.2.
You can verify with show ip os database on both routers.
06-11-2007 10:39 AM
Hi Joe,
It will always get subnetmask i.e. configured at Interface.
If you are looking concept wise.... there is priority. Interface priority is more than OSPF.
06-11-2007 11:09 AM
Actually the Hub sees the /30 route as a connected route and learns the /24 route from the spoke due to mask configured on the interface.
The wildcard mask you used under the network command enables ospf on the P2P interface and as said above ospf advertises the interface mask along with the subnet to hub.
Actually if you do a sh ip route at the spoke, you will see /24 route as connected and the /30 as one learned from OSPF from the Hub.
HTH, rate if it does
Narayan
06-11-2007 11:52 AM
Exactly guys, thanks!
I purposely configured this all this way just to understand
ospf mask behavior vs. the subnet configured on the interface... (i'm taking the lab very soon)
Any thing else would be awesome!
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