Tag Archives: OSPF

OSPFv2 vs OSPFv3 LSA’s

In this post we will talk bout the differences between OSPFv2 and OSPFv3 LSA’s An LSA (Link state advertisement) is a packet-type used by OSPF to communicate information about to network to its neighbors. OSPFv2 uses a number of different LSA’s as listed below. LSA Type 1 – Router LSA – Generated by all routers… Read More »

Juniper OSPF Conditional Default Route

In this post we will set up a conditional default route for ospf. First we have the following network diagram. The router junos1 has a bgp session to R1 and is connected to junos2 and using IBGP and OSPF. Junos2 is then connected to Junos3 via IBGP and OSPF. [edit] root# show protocols bgp group… Read More »

OSPF Interface Costs

In this example we will use OSPF Costs to allow us to load balance between links. We have 2 paths to router 2. The fist is directly connected the second is via R1. Lets first trace to R2 and see what path we are using R3#traceroute Type escape sequence to abort. Tracing the route… Read More »

Reliable Default Route – OSPF

In this post we will configure and test a reliable default route using OSPF. First we need to look at the network digram. R1, R2 and R3 are all in the same OSPF area. R3 and R4 are peering via BGP. All devices have a loopback interface x.0.0.0/8 where X is the routers number. As… Read More »

OSPF Virtual Link

In OSPF everything has to connect to the backbone area with is area 0. So if we had a situation where we had 3 areas, area 0, area 1 and area 2 and area 2 was connected to area 1 and not directly connected to area 0 then we would have a problem. This is… Read More »

How to setup basic OSPF on JunOS

Just as in the Cisco post we first need to set up the network using the below diagram Now we need to set the IP address on the interface. root@% cli root> configure Entering configuration mode [edit] root# edit interfaces em0 [edit interfaces em0] root# edit unit 0 [edit interfaces em0 unit 0] root# set… Read More »

How to setup basic OSPF on Cisco

To begin with we need to set up the network using the diagram below. Now we need to configure an IP address on interface Serial 0 on both routers R1> enable R1# configure terminal R1(config)# interface serial 0/0 R1(config-if)# ip address R1(config-if)# no shutdown R1(config-if)# end R1# R2> enable R2# configure terminal R2(config)#… Read More »