OSPF Adj on broadcast network type

I have frame-relay between 2 routers, let say R5 & R4 connected via frame-relay switch.
when i changed the network type to broadcast from the default none-broadcast on the serial interface on the routers and set the ip ospf priority to 0 on both routers, the neigh state change to 2WAY/DROTHER on both routers and the error below appears! I believe by default OSPF will always go through the DR/BDR election process when i am using broadcast even thou ip ospf priority is set to 0 the DR and BDR election will alway happen.  According to the logs below "Elect BDR 150.5.5.5", the router is electing itself as DR. when both routers are set to ip ospf priority 0, always stuck in 2WAY/DROTHER any comments? 

 


*Mar  1 00:04:23.851: %OSPF-5-ADJCHG: Process 1, Nbr 0.0.0.0 on Ethernet0/1 from
 ATTEMPT to DOWN, Neighbor Down: Dead timer expired
*Mar  1 00:04:23.851: OSPF: end of Wait on interface Ethernet0/1
*Mar  1 00:04:23.851: OSPF: DR/BDR election on Ethernet0/1
*Mar  1 00:04:23.851: OSPF: Elect BDR 150.5.5.5
*Mar  1 00:04:23.851: OSPF: Elect DR 150.5.5.5
*Mar  1 00:04:23.851: OSPF: Elect BDR 0.0.0.0
*Mar  1 00:04:23.851: OSPF: Elect DR 150.5.5.5
*Mar  1 00:04:23.851:        DR: 150.5.5.5 (Id)   BDR: none
*Mar  1 00:04:23.851: OSPF: Starting 0.0.0.0 address 183.1.45.4 on Ethernet0/1
*Mar  1 00:04:24.351: OSPF: No full nbrs to build Net Lsa for interface Ethernet
0/1
*Mar  1 00:05:17.599: OSPF: We are not DR to build Net Lsa for interface Serial1
/0

Comments

  • You say that you're running OSPF over FR, yet this output is showing logs from the Ethernet0/1 interface?  I'm confused. 

    Show ip ospf neighbor, show ip ospf interface, and show ip route ospf from both routers please.  Something else is fishy here. 

    Thanks

    Geoff

  • sorry about that. i paste the wrong logs. The interface is serial. see below

     

    *Mar  1 00:04:23.851: %OSPF-5-ADJCHG: Process 1, Nbr 0.0.0.0 on serial1/0 from
     ATTEMPT to DOWN, Neighbor Down: Dead timer expired
    *Mar  1 00:04:23.851: OSPF: end of Wait on interface Ethernet0/1
    *Mar  1 00:04:23.851: OSPF: DR/BDR election on Ethernet0/1
    *Mar  1 00:04:23.851: OSPF: Elect BDR 150.5.5.5
    *Mar  1 00:04:23.851: OSPF: Elect DR 150.5.5.5
    *Mar  1 00:04:23.851: OSPF: Elect BDR 0.0.0.0
    *Mar  1 00:04:23.851: OSPF: Elect DR 150.5.5.5
    *Mar  1 00:04:23.851:        DR: 150.5.5.5 (Id)   BDR: none
    *Mar  1 00:04:23.851: OSPF: Starting 0.0.0.0 address 183.1.45.4 on serial1/0
    *Mar  1 00:04:24.351: OSPF: No full nbrs to build Net Lsa for interface serial1/0
    *Mar  1 00:05:17.599: OSPF: We are not DR to build Net Lsa for interface Serial1/0

  • This output is still related to your Ethernet0/1 interface election .....

    *Mar  1 00:04:23.851: OSPF: end of Wait on interface Ethernet0/1
    *Mar  1 00:04:23.851: OSPF: DR/BDR election on Ethernet0/1
    *Mar  1 00:04:23.851: OSPF: Elect BDR 150.5.5.5
    *Mar  1 00:04:23.851: OSPF: Elect DR 150.5.5.5
    *Mar  1 00:04:23.851: OSPF: Elect BDR 0.0.0.0
    *Mar  1 00:04:23.851: OSPF: Elect DR 150.5.5.5
    *Mar  1 00:04:23.851:        DR: 150.5.5.5 (Id)   BDR: none

     

    Here is the output for ur serial where it tells us that we are not the DR (due to ospf priority 0) therefore we will not build Net LSA ... if both sides are set to priority 0 then they will not create Net LSA and nothing else will happen.  DR/BDR election will start only if ur priotiry is greater than 1.

    *Mar  1 00:04:23.851: OSPF: Starting 0.0.0.0 address 183.1.45.4 on serial1/0
    *Mar  1 00:04:24.351: OSPF: No full nbrs to build Net Lsa for interface serial1/0
    *Mar  1 00:05:17.599: OSPF: We are not DR to build Net Lsa for interface Serial1/0

     

    Just did a test and this is the only log you should see when both sides are set to 0.

    OSPF: Build router LSA for area 0, router ID 150.1.2.2, seq 0x80000012

  • To elaborate further on what nydimka23 wrote, this situation in my eyes would be similar to the link below.  Routers on the same broadcast segment will only form full adjacencies with the DR/BDR on the segment.  Considering that you essentially shutdown the ability for either router to run the election process and commit one to be the DR and the other a DROTHER (because two routers on a broadcast segment is essentially a point-to-point link and there are no BDR's on a point-to-point OSPF setup) you're encountering the 'Stuck in 2WAY' situation where both adjacencies are never fully setup. 

    http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094059.shtml

  • It is good to remember that broadcast and non-broadcast type ospf interfaces both require a DR to distribute LSAs between neighbors. By configuring ip ospf priority 0 on both neighbors, neither neighbor can become DR, causing stuck-in-2WAY.

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