SCSIraidGURU’s World

OSPF Virtual Link (CCNP)

OSPF no Virtual Link

OSPF with Virtual Link

This simulation is for OSPF using a virtual link to commect two Area 0 together.   I have it created for IPv4 and IPv6.   You use Router OSPF and IPv6 Router OSPF configurations.   The command

Area # virtual-link Router-id to the other router creates the bridge.  This simulation goes across Area 1 to create the virtual link.   Router-id 10.4.x.x is for OSPF iPv4 for x (iosv-x).  Router-id 10.6.x.x is for IPv6 Router OSPF.  This will show you the OSPF traffic on both IPv4 and IPv6.

Flat-1 allows my simulations out to the TFTP IPv6 Ubuntu server.   I added routes to redirect TFTP commands. 

sh run | redirect tftp://[fd00:192:168:1::5]/iosv1_ShRunBeforeVL.txt

This simulation has two OSPF area 0 that are not connected.  It could be from two companies merging.   The virtual link allows a connection on ABRs across another area to allow OSPF communication between the two Area 0 routers. 

This will show you the Sh IP OSPF databases before and after.

I will start with showing you the iosv-3 and iosv-4 before and after Sh IP OSPF Database and Sh IPv6 OSPF Database. 

On the the left iosv-1 and iosv-2 are in one OSPF area 0.   On the right iosv-5 and iosv-6 are in the other Area 0.   In the beforeVL versions, you will not see them cross over and talk.   the ABRs are isov-3 and iosv-4.

Before the virtual link



After the virtual link



iosv-3 and ios4 sh ip ospf virtual-link