10.1 INTRODUCTION

This chapter looks at the method by which IPv6 encapsulation of Internet packets involve both IPv6 and IPv4. This method can be also used with other protocol packets such as AppleTalk, IPX, CLNP, or others.

The specific method in which a packet is encapsulated and conveyed as payload within an IPv6 packet is the focus of this section. The resultant packet is referred to as an IPv6 tunnel packet. The forwarding path between the source and destination of the tunnel packet is referred to as IPv6 tunnel. The mechanism is referred to as IPv6 tunneling.

A sample illustration of IPv6 tunneling is an event where an intermediate node exerts specific routing control by determining specific forwarding paths for chosen packets. This control is acquired by looking at each initially chosen original packets or IPv6 headers which distinguish the forwarding path. Besides the overall portrayal of IPv6 tunneling mechanisms, certain methods involved for tunneling IPv6 and IPv4 packets is a main focus within this section.

10.2 TUNNELING

IPv6 tunneling is a method which creates a virtual link between two IPv6 nodes for sending data packets as payloads of IPv6 packets. When looking at this from the perspective of the two nodes, the virtual link is referred to as an IPv6 tunnel. It emerges as a point to point link whereby IPv6 performs like a link-layer protocol. The two IPv6 nodes have very specific duties.

One node encapsulates the original packets retrieved from other nodes or itself and then sends...