# OSPF DR/BDR Election explained **URL:** \ **Category:** Lessons Discussion\ **Created:** [December 20, 2016, 10:30pm UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880 "2016-12-20T22:30:31Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![ReneMolenaar](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/renemolenaar/32/488_2.png) [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)\ **Post date:** [December 20, 2016, 10:30pm UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/1 "2016-12-20T22:30:31Z")
This topic is to discuss the following lesson: > **[OSPF DR/BDR Election explained](https://networklessons.com/ospf/ospf-drbdr-election-explained)** > > OSPF does a DR/BDR election on multi-access networks. In this lesson, we will take a look how it works and how to configure the DR and BDR. ---
**Author:** ![ReneMolenaar](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/renemolenaar/32/488_2.png) [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)\ **Post date:** [June 23, 2013, 9:54pm UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/2 "2013-06-23T21:54:35Z")
Really helpful series of posts on OSPF. Thank you! ---
**Author:** ![system](https://cdn-forum.networklessons.com/uploads/default/original/1X/1d2ef66728c7fbac8377748594345a3f474fce5f.png) [@system](https://forum.networklessons.com/u/system)\ **Post date:** [July 14, 2013, 6:39pm UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/3 "2013-07-14T18:39:04Z")
Thanks for this lesson, very helpful! 🙂 ---
**Author:** ![system](https://cdn-forum.networklessons.com/uploads/default/original/1X/1d2ef66728c7fbac8377748594345a3f474fce5f.png) [@system](https://forum.networklessons.com/u/system)\ **Post date:** [August 28, 2013, 1:05pm UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/4 "2013-08-28T13:05:13Z")
Wonderful explanation!! The best I’ve found on the web. CCNA books are not so clear! Thanks! ---
**Author:** ![ReneMolenaar](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/renemolenaar/32/488_2.png) [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)\ **Post date:** [August 28, 2013, 1:48pm UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/5 "2013-08-28T13:48:59Z")
Thanks Davide, glad to hear you like it! ---
**Author:** ![system](https://cdn-forum.networklessons.com/uploads/default/original/1X/1d2ef66728c7fbac8377748594345a3f474fce5f.png) [@system](https://forum.networklessons.com/u/system)\ **Post date:** [August 29, 2013, 7:53pm UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/6 "2013-08-29T19:53:27Z")
simply awesome!!! Thanks a lot.. ---
**Author:** ![ibmufa](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/i/3e96dc/32.png) [@ibmufa](https://forum.networklessons.com/u/ibmufa)\ **Post date:** [September 24, 2013, 2:02pm UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/7 "2013-09-24T14:02:16Z")
One of the best explanations I have ever come across. You make things seem easy. I haven’t started configurations of OSPF yet but I get it ---
**Author:** ![system](https://cdn-forum.networklessons.com/uploads/default/original/1X/1d2ef66728c7fbac8377748594345a3f474fce5f.png) [@system](https://forum.networklessons.com/u/system)\ **Post date:** [November 27, 2013, 10:34am UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/8 "2013-11-27T10:34:27Z")
Hi! Can you explain to me please, where I can use DROTHER and examples of its use? Than you! P.S. Sorry for my bad English! ) ---
**Author:** ![system](https://cdn-forum.networklessons.com/uploads/default/original/1X/1d2ef66728c7fbac8377748594345a3f474fce5f.png) [@system](https://forum.networklessons.com/u/system)\ **Post date:** [January 4, 2014, 2:30am UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/9 "2014-01-04T02:30:16Z")
Hi Rene, Just to let you know that on the multi-segment picture, the networks don’t match with the output below. On the right side, you should change to 192.168.23.0/24. Not a big ideal, just to avoid confusing more distracted people 🙂 AF ---
**Author:** ![ReneMolenaar](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/renemolenaar/32/488_2.png) [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)\ **Post date:** [January 14, 2014, 7:30pm UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/10 "2014-01-14T19:30:59Z")
Basically only the DR and BDR are important, all other routers are DROTHERS. In case the DR and/or BDR fails one of the currently DROTHERS might become DR/BDR. ---
**Author:** ![system](https://cdn-forum.networklessons.com/uploads/default/original/1X/1d2ef66728c7fbac8377748594345a3f474fce5f.png) [@system](https://forum.networklessons.com/u/system)\ **Post date:** [January 23, 2014, 7:25pm UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/11 "2014-01-23T19:25:34Z")
you are the best.thanks for useful lesson ---
**Author:** ![system](https://cdn-forum.networklessons.com/uploads/default/original/1X/1d2ef66728c7fbac8377748594345a3f474fce5f.png) [@system](https://forum.networklessons.com/u/system)\ **Post date:** [May 27, 2014, 4:02am UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/12 "2014-05-27T04:02:33Z")
Hello, Thank you very much for explanation. I don’t actually know what DR and BDR do and why should we use them in OSPF protocol. I’d appreciate it if you explain that as well. ---
**Author:** ![ReneMolenaar](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/renemolenaar/32/488_2.png) [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)\ **Post date:** [August 6, 2014, 11:46am UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/13 "2014-08-06T11:46:37Z")
Hi Mey, I explained why we need a DR / BDR in this tutorial: > **[Introduction to OSPF](https://networklessons.com/ospf/introduction-to-ospf)** > > This lesson explains the basics of OSPF, a link-state IGP routing protocol that builds a LSDB by exchanging LSAs. Rene ---
**Author:** ![e8cheng](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/e/a4c791/32.png) [@e8cheng](https://forum.networklessons.com/u/e8cheng)\ **Post date:** [November 13, 2014, 7:18pm UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/14 "2014-11-13T19:18:04Z")
Hi, Rene, In your examples, such as the first one, the output of command `Nancy#show ip ospf neighbor` shows both the 2 "Interface"s as “FastEthernet0/0” Is the interface a interface on Nancy? Or a interface on the neighbor? In the 2nd example (2 multi-accesssegments), the output of command `Donna#show ip ospf neighbor` shows 2 "Interface"s as FastEthernet1/0 and FastEthernet0/0. but there is no interface FastEthernet1/0 in that diagram. Would please update that diagram? Thanks ---
**Author:** ![e8cheng](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/e/a4c791/32.png) [@e8cheng](https://forum.networklessons.com/u/e8cheng)\ **Post date:** [November 13, 2014, 7:34pm UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/15 "2014-11-13T19:34:13Z")
I think I have figured out that the “Interface” is the interface on this router instead of the one on the neighbor router. Please confirm. Thanks! ---
**Author:** ![ReneMolenaar](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/renemolenaar/32/488_2.png) [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)\ **Post date:** [November 13, 2014, 7:35pm UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/16 "2014-11-13T19:35:57Z")
Hi Chang Shong C, The first example is correct. We have a multi-access network so you can have multiple OSPF neighbors on one interface. The 2nd example with the diagram had an error…I just fixed the interface number, thanks for letting me know! Rene ---
**Author:** ![sbjalali](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/s/858c86/32.png) [@sbjalali](https://forum.networklessons.com/u/sbjalali)\ **Post date:** [January 28, 2015, 7:24am UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/17 "2015-01-28T07:24:38Z")
Excellent! ---
**Author:** ![rajmannar](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/r/eb8c5e/32.png) [@rajmannar](https://forum.networklessons.com/u/rajmannar)\ **Post date:** [May 6, 2015, 6:07am UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/18 "2015-05-06T06:07:30Z")
Hello, I don’t have "#clear ip ospf process " this command on my router simulator. It only has clear ip options and no “ospf” option. Any workaround? thanks ---
**Author:** ![ReneMolenaar](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/renemolenaar/32/488_2.png) [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)\ **Post date:** [May 6, 2015, 9:24am UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/19 "2015-05-06T09:24:30Z")
That is strange. What simulator do you use? This is a very common command and if OSPF is supported, it should be included. ---
**Author:** ![rajmannar](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/r/eb8c5e/32.png) [@rajmannar](https://forum.networklessons.com/u/rajmannar)\ **Post date:** [May 6, 2015, 1:17pm UTC](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880/20 "2015-05-06T13:17:07Z")
I am using Cisco Packet Tracer 5.3.0.0088 [Next page](https://forum.networklessons.com/t/ospf-dr-bdr-election-explained/880.md?page=2)