NETBIOS is a programming interface that allows I/O requests to be sent to and received from a remote computer and it hides the networking hardware from applications. NETBEUI is NetBIOS extended user interface. A transport protocol designed by microsoft and IBM for the use on small subnets.

 Explain redirector
Redirector is software that intercepts file or prints I/O requests and translates them into network requests. This comes under presentation layer.

 Explain Beaconing
The process that allows a network to self-repair networks problems. The stations on the network notify the other stations on the ring when they are not receiving the transmissions. Beaconing is used in Token ring and FDDI networks.

 Explain terminal emulation, in which layer it comes
Telnet is also called as terminal emulation. It belongs to application layer.

 Explain frame relay, in which layer it comes
Frame relay is a packet switching technology. It will operate in the data link layer.

 What do you meant by “triple X” in Networks
The function of PAD (Packet Assembler Disassembler) is described in a document known as X.3. The standard protocol has been defined between the terminal and the PAD, called X.28; another standard protocol exists between hte PAD and the network, called X.29. Together, these three recommendations are often called “triple X”

 Explain SAP
Series of interface points that allow other computers to communicate with the other layers of network protocol stack.

 Explain subnet
A generic term for section of a large networks usually separated by a bridge or router.

 Explain Brouter
Hybrid devices that combine the features of both bridges and routers.

 How Gateway is different from Routers
A gateway operates at the upper levels of the OSI model and translates information between two completely different network architectures or data formats.