OSPF problems

[vitumbiko nkhwazi]

Hello All.

does OSPF only work on point-to-point links? i have OSPF configured on some links which are not on point-to-point links but OSPF is not forming neighbor relations but with routers on point-to-point links OSPF is working fine. what is it?

Thanks

[Nagendra Kumar Nainar]

Hi,

With right configuration, OSPF will work on any link (P2P or broadcast). Can you share the cofiguration?.

-Nagendra

[lucentmoon]

By default ospf running over point-to-point links use multicast hellos to form the neighbor relationship.  My guess is that you need a neighbor statement under the ospf process.  As some link types by default dont send the multicast hellos

The configuration needed depends on the network type of the links.  Here is a quick break down of the different network types and requirements.

http://www.ccietalk.com/2008/07/14/ospf-network-types

[turnera]

Are you using the following command in your point to multipoint link configurations?

ip ospf network point-to-multipoint

This will need to be entered at every link location.

This may help with your current problem.

[paul driver]

HI,

Opsf can be defined with different types which can be configured with the default hello times for neighbor establishment.

                                           Dr/BDR election -   dyanmic discovery of neighbour    multiple routers in subnet

Broadcast networks ( ethernet)      yes                     yes                               yes   10 sec hello / 40 sec dead

NBMA networks ( frame-relay)       yes                    n/a                         yes  30 sec hello / 120 sec dead

Point -to-point                         n/a                yes                            n/a   10 sec hello / 40 sec dead

Point-to-multipoint                        n/a                    yes                               yes   30 sec hello / 120 sec dead

Point-to-multipoint non-broadcast   n/a                  n/a                      yes   30 sec hello / 120 sec dead

Virtual link                                   n/a                           n/a                                n/a

Also these are compatible

Point -to-Point & Point-to-Multipoint

Point -to-Point & Point-to-Multipoint non-broadcast

( required to change hello value to same)

Broadcast & non-broadcast

Also all the above fit into one of two network types:

Transit networks have two or more attached router - packets that pass through "transit"

Stub network have a single attached router - packets have source or destination addresses belong to it.

res

Paul