An anycast is a communication process that involves transmitting data from a point of origin to a single point of termination. The determination of where the anycast is received is often determined by factors such as distance between the sender and the receiver. This means that while there may be several different termination points that are capable of receiving the communication, those other receivers do not receive the data directly. Instead, the original recipient initiates a second anycast, passing the data on to the next nearest receiver. The process continues until all available recipients within the group have received and assimilated the data.
The process associated with an anycast is slightly different from a unicast. While both approaches call for a point to point transmission of data from the point of origin to a single point of termination, the recipient does not then pass the data on to others in the group. Instead, the originator of the unicast conducts single transmissions to each group member. An anycast is also different from a multicast, where the originator communicates data to several different recipients at one time.
Depending on the exact application, the use of an anycast may be a more efficient way to communicate with various points of termination. By initiating the single broadcast to the nearest recipient or receiver, the sender has completed the task, effectively freeing up the resources that were in use during the communication. This is in contrast to situations where the same sender must contact multiple recipients, either individually or simultaneously, resulting in the use of more resources over a slightly longer period of time.
Anycast routing can be used in different Internet applications as well as in sending and receiving communications between different systems within a local network. It is important that the recipient that is identified by the sender as the best or nearest may vary from one instance to the next. Factors such as the type of data being transmitted, or other protocols that are programmed into the process may lead to situations in which one recipient is considered the best option for visual data, another for audio data, and still another for audio-visual data.
As with any type of data transmission, an anycast does present some risks in terms of interception of the data while it is en route to the intended recipient. For this reason, security protocols that encrypt or otherwise prevent the data from being diverted, copied and then released for delivery to its original point of termination are often integrated into various situations. Doing so helps to minimize the chances of what is known as a man-in-the-middle security breach, in which data is captured, analyzed, and altered in some manner before being passed on to the termination point.