Cisco and Juniper Routers : OSPF point to multipoint configurations

Today I am going to discuss on the OSPF configuration part, As you already know about the OSPF protocol and the network types in OSPF.

OSPF Point to Multipoint Networks
In the point-to-multipoint configurations, we need to emulate broadcast capability, it seeks to organise the PVCs into a collection of point-to-point networks. In the case of OSPF point to multipoint networks, the hello packets must still be replicated and transmitted individually to each neighbor, but the multipoint approach offers two distinct advantages: no DR/BDR is needed, and the emulated point-to-point links can occupy a common subnet.

Apart from all these today I am going to have sample configurations on OSPF point to multipoint networks.

Here in this article I am going to take a topology of OSPF point to multipoint network and let you know the basic configurations on all the routers in the topology.
Fig 1.1- OSPF topology

So we have the four routers, Router 1, Router 2, Router 3 and Router 4 all are in the point to multipoint networks. Below are the configurations on all the four routers below on Cisco routers. All the IPs used in this topology has no relevance with any of the live networks or with any enterprise networks.

Click on the picture for more clarity.
Fig 1.2- OSPF Point to Multipoint Configurations
So above is the example shows the basic configurations on all the Cisco routers, now I will take a single example where i can show you the same type of configurations on Juniper router as well.

Juniper Routers sample OSPF point to Multipoint Network Configuration

When you configure the interface, specify either the IP address or the interface name. Using both the IP address and the interface name produces an invalid configuration.

In this example, you configure the Ethernet interface xe-2/0/0.0 as an OSPFv2 interface in OSPF area and specify as the neighbor’s IP address.

Below are the basic configuration of OSPF point to Multipoint configurations on Juniper Routers

NB_Router# set interfaces xe-2/0/0 unit 0 family inet address
NB_Router# edit protocols ospf area
NB_Router# set interface xe-2/0/0 neighbor
NB_Router# set interface xe-2/0/0 interface-type p2mp

NB_Router# show interfaces
unit 0 {
family inet {
NB_Router# show protocols ospf
                   interface xe-2/0/0 {
                   interface-type p2mp;