RFC 2473 (rfc2473) - Page 4 of 36

Generic Packet Tunneling in IPv6 Specification

RFC 2473            Generic Packet Tunneling in IPv6       December 1998


   inner tunnel

        a tunnel that is a hop (virtual link) of another tunnel.

   outer tunnel

        a tunnel containing one or more inner tunnels.

   nested tunnel packet

        a tunnel packet that has as payload a tunnel packet.

   nested tunnel header

        the tunnel header of a nested tunnel packet.

   nested encapsulation

        encapsulation of an encapsulated packet.

   recursive encapsulation

        encapsulation of a packet that reenters a tunnel before exiting
        it.

   tunnel encapsulation limit

        the maximum number of nested encapsulations of a packet.

3. IPv6 Tunneling

   IPv6 tunneling is a technique for establishing a "virtual link"
   between two IPv6 nodes for transmitting data packets as payloads of
   IPv6 packets (see Fig.1).  From the point of view of the two nodes,
   this "virtual link", called an IPv6 tunnel, appears as a point to
   point link on which IPv6 acts like a link-layer protocol.  The two
   IPv6 nodes play specific roles.  One node encapsulates original
   packets received from other nodes or from itself and forwards the
   resulting tunnel packets through the tunnel.  The other node
   decapsulates the received tunnel packets and forwards the resulting
   original packets towards their destinations, possibly itself. The
   encapsulator node is called the tunnel entry-point node, and it is
   the source of the tunnel packets. The decapsulator node is called the
   tunnel exit-point, and it is the destination of the tunnel packets.







Conta & Deering             Standards Track