IOS to Junos (I2J) Tips
IOS to Junos (I2J) Tips

OSPF Virtual link.

[ Edited ]
‎04-03-2012 06:11 PM

 

   Hello.

 

   This is the way to configure a ospf virtual link under IOS and JunOS. The main difference is that under IOS, the virtual link is configured under the ospf section, only have to configure the transit area and the target router id. But under JunOS, you have to configure the virtual link under the ospf and area 0.0.0.0 hierarchy. Then configure transit area and target router id.

 

  This is a easy configuration.

 

  .- Cisco configuration:

 

!

! ABR Router3.

!

interface fastethernet 0/0

 description Area 2 interface to Router4
 ip address 34.34.34.3 255.255.255.0

!

interface fastethernet 0/1

 description Area 0 Backbone.
 ip address 23.23.23.3 255.255.255.0

!
router ospf 3

 

! Fix router id, this way there will not be problems if router reloads and choose other id.

router-id 10.3.3.3

 

 ! virtual link configuration, transit area and target router id.

 area 2.2.2.2 virtual-link 10.4.4.4

 

! interface to area configuration

 network 23.23.23.0 0.0.0.255 area 0.0.0.0
 network 34.34.34.0 0.0.0.255 area 2.2.2.2

 

!

! Router4. Isolated area 0.0.0.0 interface.

!

interface fastethernet 0/0

 description Area 2 interface to Router3

 ip address 34.34.34.4 255.255.255.0

!

interface fastethernet 0/1

 description Area 0 isolated interface

 ip address 10.10.1.4 255.255.255.0

 !

 !

router ospf 4

 

! Fix router id.
 router-id 10.4.4.4

 

 ! transit area and target router id.

 area 2.2.2.2 virtual-link 10.3.3.3

! interface to area configuration.

 network 10.10.0.0 0.0.255.255 area 0.0.0.0
 network 34.34.34.0 0.0.0.255 area 2.2.2.2

 

 

 .- Junos configuration :

 

/*

 ABR Router 3

*/


/* Fix router id */

set routing-options router-id 10.3.3.3

 

set interface ge-0/0/0 description "Area 2 interface to Router4"

set interface ge-0/0/0 unit 0 family inet address 34.34.34.3/24 

set interface ge-0/0/1 description "Backbone Area interface"

set interface ge-0/0/1 unit 0 family inet address 23.23.23.3/24

 

/* Virtual link configuration, under the area 0.0.0.0, transit area and target router id */

set protocols ospf area 0.0.0.0 virtual-link neighbor-id 10.4.4.4 transit-area 2.2.2.2

 

/* interfaces and area configuration */
set protocols ospf area 0.0.0.0 interface ge-0/0/1
set protocols ospf area 2.2.2.2 interface ge-0/0/0

 

 

/*

 Router4, isolated area 0.0.0.0 interface

 */

 

/* Fix router id */

set routing-options router-id 10.4.4.4

 

set interface ge-0/0/0 description "Area 2 interface to Router3"

set interface ge-0/0/0 unit 0 family inet address 34.34.34.4/24

 

set interface ge-0/0/1 description "Area 0 isolated interface"

set interface ge-0/0/1 unit 0 family inet address 10.10.1.4/24

 

/* Virtual link under ospf area 0.0.0.0, target router id and transit area configuration */ 

set protocols ospf area 0.0.0.0 virtual-link neighbor-id 10.3.3.3 transit-area 2.2.2.2

 

/* interfaces and area configuration */
set protocols ospf area 0.0.0.0 interface ge-0/0/1
set protocols ospf area 2.2.2.2 interface ge-0/0/0

 

 

-------------------------------

Verifications.

 

 

IOS

 

show ip ospf virtual-link

show ip ospf neighbor

 

JunOS

show ospf overview

show ospf neighbor

 


 

 

Br
Alex

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you want to say thanks, the word is Kudos!!.

Thx.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

JNCIA-JUNOS, JNCIS-ENT, JNCIS-SP, JNCIP-SP.
CCNA, CCNP, Written CCIE.