RuggedRouter User Guide
Chapter 17 – C onfiguri ng Gene ric Rout ing Encapsu lation
Introduc tion
This chapter familiarizes the user with:
•Enabli ng/Disab ling GRE
•Viewin g GRE St atus

GRE Fund amentals

The RuggedRouter is able to encapsulate multicast traffic and IPv6 packets and
transport them through an IPv4 network tunnel.
The GRE tunnel can transport the traffic through any number of intermediate
networks. The key parameters for GRE in each router are the tunnel name, local
router address, remote router address and remote subnet.
Figure 146: VRR P Examp le
In the above example, Router 1 will use a GRE tunnel with a local router address of
172.16.17.18, a remote router address of 172.19.20.21, and a remote subnet of
192.168.2.0/24.

Note: I f you are connectin g to a CIS CO router, the loca l router a ddress co rresponds

to the C ISCO IOS “ source” a ddress and the remot e router address co rresponds to the

“destina tion” addr ess.

You may also set a cost for the tunnel. If another method of routing between Router1
and Router2 becomes available, the tunneled packets will flow through the lowest
cost route. You can optionally restrict the packets by specifying the local egress
device (in the case of router1, w1ppp).
174 RuggedCom
Router 2Router 1
w2pppw1ppp
172.16.17.18 172.19.20.21
192.168.1.0/8 192.168.2.0/8
192.168.1.1 192.168.2.1eth1 eth2