DR / Drother in ospf

[Adam373]

Hi i got 2 questions about DR / Drother 1-In BMA network what's it exactly every Drother share with another Drother is it just LSA or LSDB 2- and what is it exactly DR share or forward with other Drother is it LSA or LSDB

[Martin L]

Fist of all, LSA are link state advertisements packets and LSDB is link state database containing LSAs.    The rule regarding exchanging LSDB contents means that only routers in the Full state (Full/DR/BDR) are allowed to exchange LSAs. DR/BDR with DROthers do But DRother routers do not exchange LSU/LSA packets directly with each others.  DROther router does exchange packets with DR so they will have identical copy of Database (LSDB). All routers in the same area must have identical database.

Any new or updated LSA is sent to DR, then DR sends LSU info to others

Regards, ML
**Please Rate All Helpful Responses **

[Richard Burts]

The original post asks 2 questions:

1-In BMA network what's it exactly every Drother share with another Drother? In a multi access network Drother does not share any LSAs or LSDB etc with other Drother.

2- and what is it exactly DR share or forward with other Drother? In a multi access network the DR/BDR forms a full adjacency with all Drother. So the result is that the contents of the LSDB are the same on the Drother and the DR/BDR.

[Spooster IT Services]

Hi Adam373 ,

   - LSDB is a database , maintaining details of Different LSA's  , While there are multiple LSA's in  OSPF which carry different details about the OSPF topology and share them in the OSPF network 

Note: https://networklessons.com/ospf/ospf-lsa-types-explained ( use this link to know about Different type of LSA's) 

- Now DRO & DRO are in 2WAY/DRO  adjacency with each other ( In BMA or NBMA network ) , so in this state of adjacency nothing is going to be shared between the two routers .

- DRO & BDR are in FULL state with each other , So the DRO's are going to share their LSDB with the DR & then the DR will flood the LSDB to other DRO's in the area. 

Thus keeping the LSDB same in a particular area .