Editing IP address (section)

==Routing==
IP addresses are classified into several classes of operational characteristics: unicast, multicast, anycast and broadcast addressing.

===Unicast addressing===
{{Unreferenced section|date=January 2021}}
The most common concept of an IP address is in [[unicast]] addressing, available in both IPv4 and IPv6. It normally refers to a single sender or a single receiver, and can be used for both sending and receiving. Usually, a unicast address is associated with a single device or host, but a device or host may have more than one unicast address. Sending the same data to multiple unicast addresses requires the sender to send all the data many times over, once for each recipient.

===Broadcast addressing===
[[Broadcasting (networking)|Broadcasting]] is an addressing technique available in IPv4 to address data to all possible destinations on a network in one transmission operation as an ''all-hosts broadcast''. All receivers capture the network packet. The address {{IPaddr|255.255.255.255}} is used for network broadcast. In addition, a more limited directed broadcast uses the all-ones host address with the network prefix. For example, the destination address used for directed broadcast to devices on the network {{IPaddr|192.0.2.0|24}} is {{IPaddr|192.0.2.255}}.<ref>{{Cite web |date=13 May 2022 |title=What is a broadcast address? |url=https://www.ionos.com/digitalguide/server/know-how/broadcast-address/ |access-date=2022-06-08 |website=IONOS Digitalguide |language=en}}</ref>

IPv6 does not implement broadcast addressing and replaces it with multicast to the specially defined all-nodes multicast address.

===Multicast addressing===
A [[multicast address]] is associated with a group of interested receivers. In IPv4, addresses {{IPaddr|224.0.0.0}} through {{IPaddr|239.255.255.255}} (the former [[Classful network|Class D]] addresses) are designated as multicast addresses.{{Ref RFC|5771}} IPv6 uses the address block with the prefix {{IPaddr|ff00::|8}} for multicast. In either case, the sender sends a single [[datagram]] from its unicast address to the multicast group address and the intermediary routers take care of making copies and sending them to all interested receivers (those that have joined the corresponding multicast group).

===Anycast addressing===
Like broadcast and multicast, [[anycast]] is a one-to-many routing topology. However, the data stream is not transmitted to all receivers, just the one which the router decides is closest in the network. Anycast addressing is a built-in feature of IPv6.{{Ref RFC|2526}}{{Ref RFC|4291}} In IPv4, anycast addressing is implemented with [[Border Gateway Protocol]] using the shortest-path [[Metrics (networking)|metric]] to choose destinations. Anycast methods are useful for global [[Load balancing (computing)|load balancing]] and are commonly used in distributed [[DNS]] systems.