User Guide

224 Chapter : Multicasting
Router User Guide
GRE can encapsulate a wide variety of protocol packet types inside IP tunnels, creating a virtual
point-to-point link between routers at remote points over an IP network. An IP tunnel is a logical
interface that provides a way to encapsulate passenger packets inside a transport protocol. By
connecting multiprotocol subnetworks in a single-protocol backbone environment, IP tunneling
using GRE allows network expansion across a single-protocol backbone environment.
For more information on GRE, refer to the GRE Configuration Guide.