oriented, for similar reasons.
recovery. However, Frame Relay and ATM are two examples in which the protocols are
connection-oriented but the protocol does not provide error recovery. Table 3-4 provides some
example protocols and tells whether they are connection-oriented and error-recovering.
or to be connection-oriented and to also perform error recovery. In fact, many connection-
oriented protocols exchange information important to error recovery when the connection is
established.
header or trailer with a frame check sequence (FCS) or similar field can be used to detect bit
errors in the PDU. Error detection uses the FCS to detect the error, which results in discarding
the PDU. However, error recovery implies that the protocol reacts to the lost data and somehow
causes the data to be retransmitted. An example of error recovery is shown later in this section.
used synonymously. You will most likely see the use of the term connection-oriented in Cisco
documentation.
always defined as also being connection-oriented. In the current ICND course, part of the
official Cisco CCNA training path, those references have been removed. If you are studying
using an older ICRC or CRLS course book, pay particular attention to the comparisons made
about connection orientation and error recovery in this book.
(NetWare), X.25
connections, PPP
protocols, 802.3, 802.5