Using GRE Tunnel as a OSPF Virtual-Link

GRE - Simple Redirecting Encapsulation, is really a method of tunneling data in one router to an alternative. Packets of just one redirecting project - PASSANGER PROCESS are being encapsulated directly into another redirecting project - TRANSPORTATION PROCESS.

In this case in point we have a ought to set up the actual online connectivity concerning several OSPF Locations which can be definitely not linked with the location 0, and all of us do not desire to utilize Virtual Links.
GRE is really a fairly basic notion, you should configure the subsequent for the EACH ENDS on the tunnel:

1. Build a Tube User interface and assign the actual IP Target

(config)#int tunnel 1
(config-if)#ip include 172. twenty five. 185. 3 255. 255. 255. 0

a couple of. Define the original source plus the VACATION SPOT on the tunnel

(config-if)#tunnel source 100. 10. 34. 3
(config-if)#tunnel destination 100. 10. 34. four

When we have been employing OSPF then your Tube subnet ought to be marketed with the "network" order on both equally comes to an end on the tunnel.

(config-router)#network 172. twenty five. 185. 0 0. 0. 0. 255 region 0

*The IP Target on the Tube Must be marketed directly into Place 0!!!

You will see that the actual OSPF Friend is going to be produced for the Tube 1 screen.

Cisqueros_R4#show ip ospf neighbour

Friend IDENTIFICATION Pri Talk about Dead Moment Target User interface
3. 3. 3. 3 0 FULL/ - 00: 00: 38 172. twenty five. 185. 3 Tunnel1 <--- GRE-Neighbor
3. 3. 3. 3 0 FULL/ - 00: 00: 38 100. 10. 34. 3 Serial1/0. 43
5. 5. 5. 5 1 FULL/DR 00: 00: 38 100. 10. 1 out of 3. 5 GigabitEthernet5/12