ルーティング面でのIPv6移行（用語）

   This paper uses the following terminology:

   node      - a protocol module that implements IPv4 or IPv6.

   router    - a node that forwards packets not explicitly
               addressed to itself.

   host      - any node that is not a router.

   border router - a router that forwards packets across
               routing domain boundaries.

   link      - a communication facility or medium over which
               nodes can communicate at the link layer, i.e., the layer
               immediately below internet layer.

   interface - a node's attachment to a link.

   address   - an network layer identifier for an interface or
               a group of interfaces.

   neighbors - nodes attached to the same link.

   routing domain - a collection of routers which coordinate
               routing knowledge using a single routing protocol.

   routing region (or just "region")  - a collection of routers
               interconnected by a single internet protocol (e.g. IPv6)
               and coordinating their routing knowledge using routing
               protocols from a single internet protocol stack. A
               routing region may be a superset of a routing domain.

   tunneling  - encapsulation of protocol A within protocol B,
               such that A treats B as though it were a datalink layer.

   reachability information - information describing the set of
               reachable destinations that can be used for packet
               forwarding decisions.

   routing information - same as reachability information.

   address prefix - the high-order bits in an address.

   routing prefix - address prefix that expresses destinations
               which have addresses with the matching address prefixes.
               It is used by routers to advertise what systems they are
               capable of reaching.

   route leaking - advertisement of network layer reachability
               information across routing region boundaries.