OSPF Default Route on Juniper

Juniper, OSPF, Topology, rjlogs, GNS3, Junos

Continue the previous post “Configure OSPF on Juniper” , now we will configure the default route.

The scenario is IP loopback interface of J1 ( will not advertised through OSPF, but J2 and J3 will reach it through the default route that injected into OSPF.

First of all, remove the loopback interface of J1 from OSPF :

root@J1# edit protocols ospf area 0

[edit protocols ospf area]
root@J1# delete interface lo0.0

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OSPF Virtual Link

In OSPF Multi Area, all area must be connected to the backbone area (area 0), in order to communicate each other. Inter area routing will through the backbone area (area 0). If there’s area that isn’t connected to the backbone area we can setup a virtual link.

OSPF, Virtual Link, Cisco, Routing Protocol, GNS3

Based on topology above, area 2 doesn’t have connection/route to other area, since it’s not connected to the backbone area (area 0).

In this case, we can setup a Virtual Link from R4 to R2 and vice versa, from R2 to R4.

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EtherChannel – Port Link Aggregation

EtherChannel or other vendors call this Smartgroup, is  a port link aggregation technology. In other words, a technology which is used to combine several physical links between switches or routers into one logical connection and treat them as single link.

A connection with a single link.

switch, etherchannel

Add another link to get more than 1 Gbps will not work, because Spanning-tree protocol (STP) will block redundant links to prevent a loop.

etherchannel, stp, spanning-tree

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