cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
2233
Views
0
Helpful
6
Replies

OSPF BDR and DR-OTHER relations

Hello,

 

I was wondering if DR have FULL relation with all other routers BDR and DR-OTHER, then what relation is between the BDR and DR-OTHER ? Is it also full or its 2WAY and it is switching to FULL when BDR becomes DR ?

6 Replies 6

Rolf Fischer
Level 9
Level 9

Hi,

all routers form full adjacencies with DR and BDR on broadcast- and NBMA networks.

Link: RFC 2328 Section 7.4: The Backup Designated Router

 

Regards,

Rolf

Hello,

But what is the relation between BDR and DR-OTHER, 2WAY or FULL ?

Full.


all routers form full adjacencies with DR and BDR on broadcast- and NBMA Networks.


Perhaps I should have been clearer.

All routers (DR, BDR, DROther) form full adjacencies (only) with neighbor routers which are the DR or the BDR for that network.

DR always forms full adjacency with all other OSPF routers on that segment (BDR and DR-other).

BDR always forms full adjacency with all other OSPF routers on that segment (DR and DR-other).

DR-other forms full adjacency with DR and BDR and 2 way with other DR-other.

If DR fails then BDR becomes new DR and already has full adjacency with all other OSPF routers on that segment.

A new BDR is selected and the new BDR forms full adjacency with all other OSPF routers on that segment.

 

HTH

 

Rick

HTH

Rick

Hello

DR/BDR = Full/BDR
BDR/DR = Full/DR
DR/Drother = Full/DROTHER
Drother/DR = Full/DR
Drother/BDR = Full/BDR
Drother/Drother = 2WAY/DROTHER

 

 


Please rate and mark as an accepted solution if you have found any of the information provided useful.
This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul
Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community:

Innovations in Cisco Full Stack Observability - A new webinar from Cisco