Hi Marc, Ok. But isn't the broadcast statement on my frame maps taking care of underlying connectivity for OSPF ?
No i only put them on the hub, seemed more logical to me. On Jul 22, 2011, at 2:23 PM, marc abel wrote: > Yes, you set the Hub as the DR because it is the only one with a full > mesh to the others. As for the advantage of broadcast type over NBMA, > two that I can think of. 1. You don't need neighbor statements (but > you do need the broadcast on your frame maps). 2. Faster timers > > As for your neighbors below, did you have neighbor statements on R4 > and R5? You only have to have the neighbor statement on one side to > bring up the relationship. > > On Fri, Jul 22, 2011 at 7:01 AM, Alef <[email protected]> wrote: >> So i am playing around with OSPF. FR cloud with a hub, R2 and neighbors R4, >> R5 and R6. >> No adjacencies are formed yet. I add some neighbors on the hub. No ospf >> network types are defined, normal NBMA FR cloud. >> >> Below is what happened when i add neighbors, remove them again, and the ospf >> adjacencies keep forming despite that these are not configured on the hub >> anymore. Not until the ospf network type broadcast is defined they really >> don't come up anymore. Does this has something to do with the DR (maybe R2, >> didn't check) still has a link-state database and communicates it back to >> the neighbors. If so, wouldn't that be some violation of RFC? Doesn't seem >> right if i remove the neighbors they still come up! Is there some purge time >> for it to be removed from the database? >> >> Some questions: >> -Why do we have to set the hub to be the DR? Is it because the hub is the >> one who has a full mesh to all the pvc's and the others don't ? >> -And what is the benefit of setting it to the ip ospf network broadcast >> statement over say nbma ? A DR gets elected on broadcast network type as >> well. >> >> Regards, >> Alef >> >> R2(config-if)#router ospf 1 >> R2(config-router)#neighbor 150.50.255.4 >> R2(config-router)#neighbor 150.50.255.5 >> R2(config-router)#neighbor 150.50.255.6 >> R2(config-router)#do sh ip ospf neigh >> >> Neighbor ID Pri State Dead Time Address Interface >> N/A 0 ATTEMPT/DROTHER 00:01:47 150.50.255.4 Serial0/1/0 >> N/A 0 ATTEMPT/DROTHER 00:01:48 150.50.255.5 Serial0/1/0 >> N/A 0 ATTEMPT/DROTHER 00:01:50 150.50.255.6 Serial0/1/0 >> R2(config-router)# >> Jul 22 11:41:25.194: %OSPF-5-ADJCHG: Process 1, Nbr 150.50.4.4 on >> Serial0/1/0 from LOADING to FULL, Loading Done >> Jul 22 11:41:25.290: %OSPF-5-ADJCHG: Process 1, Nbr 150.50.5.5 on >> Serial0/1/0 from LOADING to FULL, Loading Done >> Jul 22 11:41:25.290: %OSPF-5-ADJCHG: Process 1, Nbr 150.50.6.6 on >> Serial0/1/0 from LOADING to FULL, Loading Done >> >> Ok. Now i remove the adjacencies. >> >> R2(config-router)#no neighbor 150.50.255.4 >> R2(config-router)#no neighbor 150.50.255.5 >> R2(config-router)#no neighbor 150.50.255.5 >> Jul 22 11:41:44.274: %OSPF-5-ADJCHG: Process 1, Nbr 150.50.4.4 on >> Serial0/1/0 from FULL to DOWN, Neighbor Down: Neighbor deconfigured >> R2(config-router)#no neighbor 150.50.255.6 >> R2(config-router)# >> Jul 22 11:41:45.614: %OSPF-5-ADJCHG: Process 1, Nbr 150.50.5.5 on >> Serial0/1/0 from FULL to DOWN, Neighbor Down: Neighbor deconfigured >> R2(config-router)# >> Jul 22 11:41:46.922: %OSPF-5-ADJCHG: Process 1, Nbr 150.50.6.6 on >> Serial0/1/0 from FULL to DOWN, Neighbor Down: Neighbor deconfigured >> >> R2(config-router)#do sh ip ospf neigh >> >> No more neighbors. Great. >> >> R2(config-router)#do sh ip ospf neigh >> Jul 22 11:41:58.706: %OSPF-5-ADJCHG: Process 1, Nbr 150.50.5.5 on >> Serial0/1/0 from LOADING to FULL, Loading Done >> Jul 22 11:41:58.786: %OSPF-5-ADJCHG: Process 1, Nbr 150.50.4.4 on >> Serial0/1/0 from LOADING to FULL, Loading Done >> R2(config-router)#do sh ip ospf neigh >> >> Neighbor ID Pri State Dead Time Address Interface >> 150.50.4.4 1 FULL/DROTHER 00:01:58 150.50.255.4 Serial0/1/0 >> 150.50.5.5 1 FULL/DR 00:01:58 150.50.255.5 Serial0/1/0 >> R2(config-router)#do sh ip ospf neigh >> >> Neighbor ID Pri State Dead Time Address Interface >> 150.50.4.4 1 FULL/DROTHER 00:01:58 150.50.255.4 Serial0/1/0 >> 150.50.5.5 1 FULL/DR 00:01:58 150.50.255.5 Serial0/1/0 >> R2(config-router)# >> Jul 22 11:42:04.322: %OSPF-5-ADJCHG: Process 1, Nbr 150.50.6.6 on >> Serial0/1/0 from LOADING to FULL, Loading Done >> R2(config-router)#do sh ip ospf neigh >> >> Neighbor ID Pri State Dead Time Address Interface >> 150.50.4.4 1 FULL/DROTHER 00:01:58 150.50.255.4 Serial0/1/0 >> 150.50.5.5 1 FULL/DROTHER 00:01:58 150.50.255.5 Serial0/1/0 >> 150.50.6.6 1 FULL/DR 00:01:57 150.50.255.6 Serial0/1/0 >> >> What? They are back again. Let me clear the OSPF process. >> R2(config-router)#do clear ip ospf proc >> Reset ALL OSPF processes? [no]: y >> R2(config-router)# >> Jul 22 11:42:16.086: %OSPF-5-ADJCHG: Process 1, Nbr 150.50.4.4 on >> Serial0/1/0 from FULL to DOWN, Neighbor Down: Interface down or detached >> Jul 22 11:42:16.086: %OSPF-5-ADJCHG: Process 1, Nbr 150.50.5.5 on >> Serial0/1/0 from FULL to DOWN, Neighbor Down: Interface down or detached >> Jul 22 11:42:16.086: %OSPF-5-ADJCHG: Process 1, Nbr 150.50.6.6 on >> Serial0/1/0 from FULL to DOWN, Neighbor Down: Interface down or detached >> R2(config-router)#do sh ip ospf neigh >> >> Neighbor ID Pri State Dead Time Address Interface >> 150.50.4.4 1 2WAY/DROTHER 00:01:31 150.50.255.4 Serial0/1/0 >> 150.50.5.5 1 2WAY/DROTHER 00:01:33 150.50.255.5 Serial0/1/0 >> 150.50.6.6 1 2WAY/DROTHER 00:01:38 150.50.255.6 Serial0/1/0 >> R2(config-router)# >> >> And back they are again. I did this twice. >> Jul 22 11:44:16.106: %OSPF-5-ADJCHG: Process 1, Nbr 150.50.4.4 on >> Serial0/1/0 from LOADING to FULL, Loading Done >> Jul 22 11:44:16.146: %OSPF-5-ADJCHG: Process 1, Nbr 150.50.5.5 on >> Serial0/1/0 from LOADING to FULL, Loading Done >> Jul 22 11:44:16.178: %OSPF-5-ADJCHG: Process 1, Nbr 150.50.6.6 on >> Serial0/1/0 from LOADING to FULL, Loading Done >> R2(config-router)#do clear ip ospf proc >> Reset ALL OSPF processes? [no]: y >> <snip> >> _______________________________________________ >> For more information regarding industry leading CCIE Lab training, please >> visit www.ipexpert.com >> >> Are you a CCNP or CCIE and looking for a job? Check out >> www.PlatinumPlacement.com >> _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com
