can also be used as a simple Data Link transport. LAPB has a tremendous
amount of overhead because of its strict timeout and windowing techniques.
You can use LAPB instead of the lower-overhead HDLC if your link is very
error prone. However, that typically is not a problem any longer.
Data Link connection protocol. HDLC is a connection-oriented protocol
at the Data Link layer, but it has very little overhead compared to LAPB.
HDLC was not intended to encapsulate multiple Network layer protocols
across the same link. The HDLC header carries no identification of the
type of protocol being carried inside the HDLC encapsulation. Because of
this, each vendor that uses HDLC has their own way of identifying the
Network layer protocol, which means that each vendor's HDLC is pro-
prietary for their equipment.
create point-to-point links between different vendors' equipment. It
uses a Network Control Protocol field in the Data Link header to iden-
tify the Network layer protocol. It allows authentication and multilink
connections and can be run over asynchronous and synchronous links.
data. ATM uses cells instead of packets that are a fixed 53-bytes long. It
also uses isochronous clocking (external clocking) to help the data move
faster. Local area network emulation (LANE) is used to allow ATM to
run on Ethernet and Token Ring LANs.