Computer Networking

note!Answer: A) B is 64 kpbs digital PCM channel for voice or data.
The ISDN B channel is a 64 kbps digital channel that carries voice or data. The D channel is the one used for signaling.

note!Answer: A) Physical layer protocol
X.21 is an ITU-T standard for digital signaling at the physical layer, used with circuit-switched networks.

note!Answer: C) Mesh topology
Mesh topology has multiple direct links between devices, so failure of one link does not disconnect the network.

note!Answer: A) Mesh
In a mesh topology, each device connects directly to every other device, so it needs n-1 ports.

note!Answer: B) Tree
A tree topology is formed by connecting multiple star networks (hubs) in a hierarchical structure.

note!Answer: B) Light wave
Fiber optic systems carry data as pulses of light generated by LEDs or lasers.

note!Answer: B) Allow user on one machine to log onto a distant machine
TELNET is a protocol that lets a user log in to and use a remote machine as a virtual terminal.

note!Answer: D) Limited configuration
ISDN principles include integrated voice and non-voice services, switched and non-switched services, and network intelligence. It is designed for flexible configuration, not limited configuration.

note!Answer: C) A Browser
Internet Explorer is a web browser, a program used to view web pages.

note!Answer: C) Internet Service Provide
ISP stands for Internet Service Provider, a company that gives users access to the internet.

note!Answer: D) 192.168.56.115
An IPv4 address has four parts, each from 0 to 255. Only 192.168.56.115 meets this rule; the others contain values above 255 or too many parts.

note!Answer: A) Transfer files to and from an internet Server
FTP (File Transfer Protocol) programs are used to upload and download files to and from a server.

note!Answer: A) Layer 7 protocols
The OSI Application layer (Layer 7) provides services such as file transfer, resource sharing and network management directly to user programs.

note!Answer: C) Presentation
The Presentation layer translates data between machine-dependent and user-readable formats, along with encryption and compression.

note!Answer: C) Application
The Application layer is the OSI layer that provides the interface between the user and the network system.

note!Answer: C) Recognize beginning and end of the data unit
In asynchronous transmission each character is framed with start and stop bits, so the receiver detects where each data unit begins and ends.

note!Answer: A) SDLC
SDLC is a bit-oriented synchronous data link protocol, while XMODEM, YMODEM and BLAST are asynchronous file transfer protocols.

note!Answer: D) Media Access Control, Logical Link Control
The IEEE divides the Data Link layer into Logical Link Control (LLC) and Media Access Control (MAC) sub-layers.

note!Answer: B) Presentation layer
Interoperability, meaning dealing with different data representations, is handled by the Presentation layer.

note!Answer: A) BLAST
BLAST is an asynchronous file transfer protocol, whereas HDLC and SDLC are synchronous link protocols and LAN is a network type.