IPv6 Terms and Concepts

As IPv6 is incorporated from the IPv4 with overcoming the drawbacks of IPv4, some terms remain same and some new terms have come into play. Below are some terms that are used with IPv6.

Node: As in simple networking terms, the Node means any devices be it a router or a host that is running IPv6.

Router: As its name suggests, it routes the packets to some path. A router acts as in intelligent device which forwards the IPv6 packets that are actually to be destined to reach some other place.

Host: This is the source and destination system that is either the sender or receiver. This does not have the capability of forwarding packets to some other destination other than itself. If it receives a packet that is not destined to it, it would drop the packet.

Upper Layer Protocol: Protocols that make use of IPv6 for transporting information from one end to another. Protocols that run on IPv6 for example, ICMPv6 and other transport Layer protocols like TCP and UDP.

Link: The routers would have some interfaces that use an IPv6 address that is in a common network i.e. IPv6 unicast address prefix. The interfaces that have this IPs are known as links.

Neighbors: Link in normal terms a neighbor that is close to one another. In terms of networking if on the same link multiple nodes are connected they are called neighbors to each other. The use of the Neighbor Discovery Protocol is done to identify neighbors and to see if the neighbor is reachable.

Network: Is a logical grouping of devices that can communicate with one another. For devices to communicate between different networks we need routing to be configured. It is interchangeably also known as Internet works.

Packet: The part that consists of the IPv6 header and the Payload. It’s a PDU (Protocol Data Unit)

Address: As the name itself represents, it is used to identify the source and destination in the IPv6 network so the IPv6 packets can travel and reach accordingly. The Address is assigned on interfaces.

MTU: The Maximum Transmission Unit is a value of the maximum bytes that can be carried in an IPv6 packet. For example for Ethernet the MTU is 1500 bytes.

Path: It is a type of MTU. A packet cannot be sent in complete as thus needs to be broken into smaller parts or fragments. The maximum allowable size of a packet being sent between source and destination without performing host fragmentation in the IPv6 network is the path MTU. Out of the available links in the path this is the smallest link MTU.

Interface: A node is usually connected to a link either physically or logically. A network adapter is an example of a physical interface. To communicate between IPv6 and IPv4 the concept of tunnel is used, this is a logical interface.

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