RFC 2473 (rfc2473) - Page 4 of 36
Generic Packet Tunneling in IPv6 Specification
Alternative Format: Original Text Document
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