Lab Objective
The objective of this lab exercise is for you to learn how to configure point-to-point GRE tunnels.
Lab Purpose:
Generic Routing Encapsulation (GRE) is IP protocol number 47; its main purpose is to encapsulate any network layer protocol. As a Cisco engineer, as well as in the Cisco CCNA exam, you will be expected to know how to implement GRE tunnels.
Certification Level:
This lab is suitable for ICND2 and CCNA certification exam preparation.
Lab Difficulty:
This lab has a difficulty rating of 7/10.
Readiness Assessment:
When you are ready for your certification exam, you should complete this lab in no more than 20 minutes.
Lab Topology:
Please use the following topology to complete this lab exercise:
Task 1:
Configure hostnames on R1 and R2 as illustrated in the topology (R1 is on the left).
Task 2:
Configure each router with its respective IPv4 addresses on both of their FastEthernet interfaces.
Task 3:
Configure a GRE tunnel (numbered 1) on each router with the respective IPv4 address (10.10.10.0/30) as per the diagram and add the following settings:
- Tunnel source is interface f0/0;
- Tunnel destination is the other router’s interface f0/0; and
- Set the tunnel mode to GRE.
Task 4:
Configure a static route on R1 to 192.168.2.0/24 via the Tunnel 1 interface, and configure a static route on R2 to 192.168.1.0/24 via the Tunnel 1 interface.
Task5:
Check the status of the interface tunnel and make sure that traffic is flowing through the tunnel as expected.
Configuration and Verification
Task 1:
For reference information on configuring hostnames, please refer to earlier labs.
Task 2:
For reference information on configuring IP addressing, please refer to earlier labs.
Task 3:
R1#config t Enter configuration commands, one per line. End with CTRL/Z. R1(config)#int Tunnel 1 R1(config-if)#ip address 10.10.10.1 255.255.255.252 R1(config-if)#tunnel source f0/0 R1(config-if)#tunnel destination 172.16.1.2 R1(config-if)#tunnel mode gre ip R2(config)#int Tunnel 1 R2(config-if)#ip address 10.10.10.2 255.255.255.252 R2(config-if)#tunnel source f0/0 R2(config-if)#tunnel destination 172.16.1.1 R2(config-if)#tunnel mode gre ip
Task 4:
R1(config)#ip route 192.168.2.0 255.255.255.0 tunnel 1 R2(config)#ip route 192.168.1.0 255.255.255.0 tunnel 1
Task 5:
R1#sh ip interface brief Interface IP-Address OK? Method Status Protocol FastEthernet0/0 172.16.1.1 YES manual up up FastEthernet0/1 192.168.1.1 YES manual up up Tunnel1 10.10.10.1 YES manual up up R2#sh ip int brief Interface IP-Address OK? Method Status Protocol FastEthernet0/0 172.16.1.2 YES manual up up FastEthernet0/1 192.168.2.1 YES manual up up Tunnel1 10.10.10.2 YES manual up up R1#show interface tunnel 1 Tunnel1 is up, line protocol is up Hardware is Tunnel Internet address is 10.10.10.1/30 MTU 1514 bytes, BW 9 Kbit/sec, DLY 500000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation TUNNEL, loopback not set Keepalive not set Tunnel source 172.16.1.1 (FastEthernet0/0), destination 172.16.1.2 Tunnel protocol/transport GRE/IP R2#show interface tunnel 1 Tunnel1 is up, line protocol is up Hardware is Tunnel Internet address is 10.10.10.2/30 MTU 1514 bytes, BW 9 Kbit/sec, DLY 500000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation TUNNEL, loopback not set Keepalive not set Tunnel source 172.16.1.2 (FastEthernet0/0), destination 172.16.1.1 Tunnel protocol/transport GRE/IP