# OSPF Non-Broadcast Network Type over Frame-Relay

**URL:** https://forum.networklessons.com/t/ospf-non-broadcast-network-type-over-frame-relay/917
**Category:** Lessons Discussion
**Created:** [December 22, 2016, 1:01am UTC](https://forum.networklessons.com/t/ospf-non-broadcast-network-type-over-frame-relay/917 "2016-12-22T01:01:21Z")
**Posts on this page:** 1
**Showing post:** 122

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### 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: [July 6, 2024, 2:27pm UTC](https://forum.networklessons.com/t/ospf-non-broadcast-network-type-over-frame-relay/917/122 "2024-07-06T14:27:07Z")

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Hello Jugal

Let’s take a step back and take a look at DRs and BDRs on any network type.

For a single network segment, OSPF will create adjacencies only between:

- the DR and BDR
- the DR and DROTHER routers
- the BDR and DROTHER routers

There is no adjacency formed between two DROTHER routers. This is the case wherever we see DRs and BDRs **regardless of network type**. That’s the very purpose of DRs and BDRs, to reduce the number of necessary adjacencies when you have multiple OSPF routers within the same network segment.

Now when it comes to NBMA networks, the only difference is that you must manually choose and define which routers will be DR and BDR using the `ip ospf priority` command. Typically, if you have a hub and spoke arrangement, the hub should be the DR and there should be no BDR. For more info on this, take a look at the following lesson:

> **[OSPF Non-Broadcast Network Type over Frame-Relay](https://networklessons.com/ospf/ospf-non-broadcast-network-type-over-frame-relay)**
>
> This lesson shows you the configuration for OSPF over Frame-Relay using the Non-Broadcast Network Type.

I hope this has been helpful!

Laz

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