×

Warning message

  • Cisco Support Forums is in Read Only mode while the site is being migrated.
  • Cisco Support Forums is in Read Only mode while the site is being migrated.

How to avoid /32 bit route in OSPF

Unanswered Question
ives.dekoninck Tue, 05/13/2003 - 23:10
User Badges:

This is normal behaviour for OSPF in point-to-multipoint networks! In fact it injects the /32 route to make it possible for a not fully meshed network to communicate.


If eg. you have a 3 routers connected like this


R1 --- R2 --- R3 and R2 uses a multipoint interface to connect then this means we will have eg a /29 on that interface. With R1 having .1 address, R2 .2 and R3 .3.


If we would use broadcast or none broadcast mode you will only see the /29 network in the routing table, so every router thinks the network is directly connected.


If R1 does not get a /32 route for the R3 router indicating it should go via R2 the routing won't work.

Yes, it is only through when R1 does not have a direct frame-relay map to R3 (though then we would create a full mesh).


If you don't want this /32 networks make the network broadcast mode though it will not be guranteed that the routing is still working.


Hope This helps,


-Ives-

Actions

This Discussion