IPv6 Anycast Addresses

IPv6 also defines an entirely new type of address and transmission, known as an “anycast”. Simply put, an anycast address is a standard IPv6 global address that is assigned to a number of different interfaces on different systems. When a packet is destined for an anycast address, the “closest” device to the sender will process the packet. In this case, the concept of “closest” is defined by the routing protocols in use on the network. At this time, anycast addresses can only be used as a destination address, cannot be used as a source address, and are only assigned to routers. A common use in IPv6 is to apply the same anycast address to all routers interfaces that connect to the same subnet. The potential uses of anycast transmission methods are being explored further by the IETF, and the technique is already finding its way into new technologies like Mobile IP.

Author: Dan DiNicolo

Dan DiNicolo is a freelance author, consultant, trainer, and the managing editor of 2000Trainers.com. He is the author of the CCNA Study Guide found on this site, as well as many books including the PC Magazine titles Windows XP Security Solutions and Windows Vista Security Solutions. Click here to contact Dan.