The structure or format of data is called ___________
Answer: A
Explanation: The structure and format of data are defined using syntax. Semantics defines how a particular pattern to be interpreted, and what action is to be taken based on that interpretation. In programming languages, syntax of the instructions plays a vital role in designing of the program.
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Network congestion occurs:
Answer: A
Correct answer: in case of traffic overloading
Congestion occurs when the traffic offered to a link or a router exceeds what it can carry, so queues build up, delay rises and packets are eventually dropped. It is a capacity problem, not a failure: nothing has broken. TCP responds by treating loss as a congestion signal and reducing its window, which is what keeps the Internet stable under load; a terminated connection or a failed node is a quite different condition.
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Which organization has authority over interstate and international commerce in the communications field?
Answer: C
Correct answer: FCC
The Federal Communications Commission regulates interstate and international communications by radio, television, wire, satellite and cable, and it allocates the radio spectrum within the United States. The ITU-T issues international telecommunication recommendations but does not regulate commerce; the IEEE develops standards such as the 802 series; and ISOC is the parent body of the IETF.
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Which one of the following extends a private network across public networks?
Answer: B
Correct answer: virtual private network
A VPN carries private traffic across a public network such as the Internet by encapsulating and usually encrypting it, so remote sites and travelling users appear to be on the same private network. An enterprise private network uses the organisation’s own leased infrastructure and does not cross public networks at all; a LAN is confined to one site; and a SAN connects storage devices rather than networks.
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A list of protocols used by a system, one protocol per layer, is called ________
Answer: B
Explanation: A protocol stack refers to a group of protocols that are running concurrently that are employed for the implementation of network protocol suite. Each layer in the network model has to use one specific protocol from the protocol stack.
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How long is an IPv6 address?
Answer: D
Correct answer: 128 bits
An IPv6 address is 128 bits, four times the 32 bits of IPv4, and is written as eight groups of four hexadecimal digits separated by colons - for example 2001:0db8:0000:0000:0000:ff00:0042:8329, which may be shortened to 2001:db8::ff00:42:8329. The enlarged space gives about \( 3.4 \times 10^{38} \) addresses, enough that address exhaustion ceases to be a design constraint. Note the unit: 128 bits, which is 16 bytes, not 128 bytes.
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Which WLAN IEEE specification allows up to 54Mbps at 2.4GHz?
Answer: C
Correct answer: G
802.11g runs in the 2.4 GHz band at up to 54 Mbps and is backward compatible with 802.11b, which is why it displaced it so quickly. 802.11a also reaches 54 Mbps but does so at 5 GHz, so it is not compatible with b or g equipment. 802.11b is limited to 11 Mbps, and 802.11n is faster than 54 Mbps and works in both bands.
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A list of protocols used by a system, one protocol per layer, is called:
Answer: B
Correct answer: protocol stack
A protocol stack is the particular set of protocols a system actually runs, one at each layer - for example Ethernet, IP, TCP and HTTP. A protocol suite is the wider family from which they are drawn, such as TCP/IP as a whole, and protocol architecture refers to the layered design itself. The stack is the concrete implementation; the suite and the architecture are the collection and the pattern.
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What PPP protocol provides dynamic addressing, authentication, and multilink?
Answer: C
Correct answer: LCP
The Link Control Protocol negotiates the characteristics of the PPP link itself: authentication with PAP or CHAP, dynamic addressing, callback, compression, error detection and multilink. NCP is the layer above it, negotiating one control protocol for each network layer protocol carried. The division is worth holding: LCP concerns the link, NCP concerns what is carried over it.
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Which command is used to upgrade an IOS on a Cisco router?
Answer: D
Correct answer: copy tftp flash
An upgrade writes a new IOS image from a TFTP server into flash, so the source is tftp and the destination flash. Reversing the two words gives copy flash tftp, which is the backup. copy tftp run and copy tftp start load configuration files rather than images, and config net merges a configuration from the network into the running one.
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