Mechanism
Communication protocols which implement reliable byte streams, generally over some unreliable lower level, use a number of mechanisms to provide that reliability. ARQ protocols have an important role for achieving reliability.
All data items are identified with a sequence number, which is used both to make sure that the data are delivered to the entity at the other end in the correct order, and to check for lost data items. The receiver sends back acknowledgements for data items which have been successfully received; a timer at the sender will cause a timeout if an acknowledgement is not received within a reasonable round trip time, and the (presumably lost) data will then be re-transmitted. To check that no data items are damaged, a checksum is used; one is computed at the sender for each block of data before it is sent, and checked at the receiver. Erroneous or missing data are reported to the sender, in order that it may retransmit the same. Any duplicated data items are discarded.
Read more about this topic: Reliable Byte Stream
Famous quotes containing the word mechanism:
“When one of us dies of cancer, loses her mind, or commits suicide, we must not blame her for her inability to survive an ongoing political mechanism bent on the destruction of that human being. Sanity remains defined simply by the ability to cope with insane conditions.”
—Ana Castillo (b. 1953)
“A mechanism of some kind stands between us and almost every act of our lives.”
—Sarah Patton Boyle, U.S. civil rights activist and author. The Desegregated Heart, part 3, ch. 2 (1962)
“Life is an offensive, directed against the repetitious mechanism of the Universe.”
—Alfred North Whitehead (1861–1947)