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2. Terminology

  1. Terminology

node a device that implements IPv6.

router a node that forwards IPv6 packets not explicitly addressed to itself. (See Note below.)

host any node that is not a router. (See Note below.)

upper layer a protocol layer immediately above IPv6. Examples are transport protocols such as TCP and UDP, control protocols such as ICMP, routing protocols such as OSPF, and internet-layer or lower-layer protocols being "tunneled" over (i.e., encapsulated in) IPv6 such as Internetwork Packet Exchange (IPX), AppleTalk, or IPv6 itself.

link a communication facility or medium over which nodes can communicate at the link layer, i.e., the layer immediately below IPv6. Examples are Ethernets (simple or bridged); PPP links; X.25, Frame Relay, or ATM networks; and internet-layer or higher-layer "tunnels", such as tunnels over IPv4 or IPv6 itself.

neighbors nodes attached to the same link.

interface a node's attachment to a link.

address an IPv6-layer identifier for an interface or a set of interfaces.

packet an IPv6 header plus payload.

link MTU the maximum transmission unit, i.e., maximum packet size in octets, that can be conveyed over a link.

path MTU the minimum link MTU of all the links in a path between a source node and a destination node.

Note: it is possible for a device with multiple interfaces to be configured to forward non-self-destined packets arriving from some set (fewer than all) of its interfaces and to discard non-self- destined packets arriving from its other interfaces. Such a device must obey the protocol requirements for routers when receiving packets from, and interacting with neighbors over, the former (forwarding) interfaces. It must obey the protocol requirements for hosts when receiving packets from, and interacting with neighbors over, the latter (non-forwarding) interfaces.

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