700 CHAPTER 49: T UNNELING CONFIGURATIONFigure 210 Network diagram for 6PEn “P” in the above figure refers to a backbone router in the network of a serviceprovider. P is not directly connected with a CE and is required to have the basicMPLS capability.When an ISP wants to utilize the existing IPv4/MPLS network to provide IPv6 trafficswitching capability through MPLS, only the PE routers need to be upgraded.Therefore, it is undoubtedly a high efficient solution that ISPs use the 6PEtechnology as an IPv6 transition mechanism. Furthermore, the operation risk ofthe 6PE technology is very low.n For more information or configuration related to 6PE, refer to “Configuring 6PE”on page 1029.TunnelingConfiguration TaskListComplete these tasks to configure the tunneling feature:Configuring an IPv6Manually ConfiguredTunnelConfigurationPrerequisitesIP addresses are configured for interfaces such as VLAN interface, Ethernetinterface, and loopback interface on the device so that they can communicate.These interfaces serve as the source interface of a tunnel interface to ensure thatthe tunnel destination address is reachable.IPv 6 networkCustomer siteCE6PE 6PEPIPv4/MPLS networkIBGPCEIPv6 networkCustomer siteTask RemarksConfiguring IPv6 over IPv4 GREtunnel“Configuring an IPv6Manually Configured Tunnel”on page 700Optional“Configuring AutomaticIPv4-Compatible IPv6 Tunnel”on page 704Optional“Configuring 6to4 Tunnel”on page 708Optional“Configuring ISATAP Tunnel”on page 714Optional“Configuring IPv4 over IPv4 Tunnel” on page 717 Optional“Configuring IPv4 over IPv6 Tunnel” on page 721 Optional“Configuring IPv6 over IPv6 Tunnel” on page 725 Optional
