33. Tunnelling
ROX™ v2.2 User Guide
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RuggedBackbone™ RX1500
The Standard Deviation
33.4. Generic Routing Encapsulation (GRE)
ROX™ is able to encapsulate multicast traffic and IPv6 packets and transport them through an IPv4
network tunnel.
A GRE tunnel can transport 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 33.47. GRE Example
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.
If you are connecting to a CISCO router (in place of Router 1 in the example above), the
local router address corresponds to the CISCO IOS "source" address and the remote router
address corresponds to the "destination" address.
You may also set a cost for the tunnel. If another method of routing between Router1 and Router2
becomes available, the tunnelled packets will flow through the lowest cost route. Optionally, you can
restrict the packets by specifying the local egress device (in the case of router1, w1ppp).
33.4.1. Generic Routing Encapsulation Configuration
Figure 33.48. Generic Routing Encapsulation (GRE) menu
The path to this menu is tunnel/gre. If GRE tunnels are configured, they will be accessible via linked
submenus.
