# Introduction to OSPF **URL:** \ **Category:** Lessons Discussion\ **Created:** [December 20, 2016, 10:26pm UTC](https://forum.networklessons.com/t/introduction-to-ospf/878 "2016-12-20T22:26:55Z")\ **Posts on this page:** 1\ **Showing post:** 162
**Author:** ![lagapidis](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/lagapidis/32/4949_2.png) [@lagapidis](https://forum.networklessons.com/u/lagapidis)\ **Post date:** [December 18, 2020, 8:22am UTC](https://forum.networklessons.com/t/introduction-to-ospf/878/162 "2020-12-18T08:22:26Z")
Hello Daniel Remember that a DR/BDR election takes place on a per-network segment basis, and not on a per-area basis. This means that an OSPF router connected to multiple network segments may be a DR on one segment, a BDR on another, and neither on a third. This post tells you much more about this situation: > [@DR/BDR election in OSPF](https://forum.networklessons.com/t/dr-bdr-election-in-ospf/6041/3): > > Hello Naresh Rene mentions that the DR/BDR are not elected on a per area basis. Actually, there can be many DR/BDRs within a single area. The DR/BDR are elected on a per broadcast domain basis. This can be more clearly seen when we define what their purpose is. If you have multiple routers within the same subnet/VLAN/broadcast domain, then you need a DR/BDR election. For example, take a look at this diagram: [image] There are two broadcast domains in this area 0: the one between R1 and R… Now to answer your question specifically, you can see in the output you provided that: - on the network segment connected to the interface with IP address 10.12.0.1 the router is a DR - on the network segment connected to the interface with IP address 10.24.0.4 the router is a BDR - on the network segment connected to the interface with IP address 10.23.0.3 the router is neither You can see this from the state column. So you see, a router can be DR, BDR, or neither at the very same time! > [@dlais1987](#): > > Network 192 168.0.0 0.0.255.255 area 0 why not just do this everytime instead of having to put in each network 192.168.2.0 and 192 168.3.0 etc. as their own statement? To answer this question, take a look at the following post: > [@How to configure OSPF for CCNA students](https://forum.networklessons.com/t/how-to-configure-ospf-for-ccna-students/879/75): > > Hello Daniel You are absolutely correct. Indeed if you wanted to you could issue the single network 0.0.0.0 255.255.255.255 command to cause all interfaces on the router to participate in OSPF. The advantage of separating the network commands in OSPF is so you can easily make modifications in the future. Let’s say you had two interfaces with IP addresses 192.168.1.1/24 and 192.168.10.1/24. Now you used the network 192.168.0.0 0.0.255.255 command to have them take part in OSPF. But at some … I hope this has been helpful! Laz --- _[View the full topic](https://forum.networklessons.com/t/introduction-to-ospf/878)._