Communication between a computer and a keyboard involves ______________ transmission.
Answer: D
Explanation: In simplex transmission, data flows in single direction which in this case refers to the data flowing from the keyboard to the computer. Another example would be of the mouse where the data flows from the mouse to the computer only.
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A set of rules that governs data communication:
Answer: A
Correct answer: Protocols
A protocol is the agreed set of rules governing a data exchange, covering syntax, semantics and timing. Standards are the documents that record such agreements formally and give them authority, and RFCs are the particular series in which the IETF publishes them. The rules themselves are the protocol; the standard and the RFC are how the rules are written down and disseminated.
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Which network topology connects every device to a single central hub or switch ?
Answer: D
Correct answer: Star
In a star topology each node has its own link to a central device, so a single cable failure isolates only one node. The weakness is the centre itself, whose failure brings down the whole network.
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In the layer hierarchy as the data packet moves from the upper to the lower layers, headers are:
Answer: A
Correct answer: Added
Each layer, as the data passes down the stack, prepends its own header containing the information its peer at the far end needs - the transport layer adds ports and sequence numbers, the network layer addresses, the data link layer MAC addresses and a trailing checksum. This is encapsulation. At the receiver the process runs in reverse: each layer strips its own header and passes the remainder up, which is decapsulation.
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What does the passive command provide to dynamic routing protocols?
Answer: B
Correct answer: Stops an interface from sending periodic dynamic updates but not from receiving updates.
The passive-interface command suppresses outgoing routing advertisements on that interface while leaving the router willing to receive them, and the network remains advertised to the rest of the topology. It is used on interfaces facing hosts or stub segments, where advertising routes wastes bandwidth and exposes the routing domain unnecessarily. Note that in EIGRP and OSPF the effect is stronger, since suppressing hellos prevents adjacencies forming at all.
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Which transmission media has the highest transmission speed in a network?
Answer: C
Correct answer: optical fiber
Optical fibre carries data as light through a glass core and offers by far the greatest bandwidth of the guided media, with speeds in the gigabits and terabits per second and very low attenuation over long distances. It is also immune to electromagnetic interference and hard to tap. Twisted pair and coaxial cable both carry electrical signals and are limited by attenuation and interference well below what fibre achieves.
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The IETF standards documents are called:
Answer: A
Correct answer: RFC
The Internet Engineering Task Force publishes its standards as Requests for Comments, numbered sequentially and never revised once issued - a change means a new RFC that obsoletes the old one. The name survives from the deliberately informal beginnings of the series in 1969, though an RFC on the standards track is now a formal specification. RFC 791 defines IP, RFC 793 TCP.
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Three or more devices share a link in ________ connection.
Answer: B
Correct answer: Multipoint
In a multipoint, or multidrop, connection more than two devices share a single link, so the capacity is shared - spatially if they can transmit at once, or in time if they must take turns. A point-to-point connection dedicates the whole link to two devices. Simplex describes the direction of flow rather than the number of devices, so it answers a different question altogether.
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What is the main reason the OSI model was created?
Answer: C
Correct answer: So different networks could communicate.
The OSI reference model was produced by ISO to allow equipment from different manufacturers, running different proprietary protocol stacks, to interoperate. Dividing the problem into seven layers with defined interfaces means each layer can be implemented independently, and a change at one layer need not disturb the others. It is a reference model rather than a protocol suite, and it long predates any single vendor’s use of it.
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What does a VLAN do?
Answer: C
Correct answer: Breaks up broadcast domains in a layer 2 switch internetwork.
A switch by itself puts every port in one broadcast domain. Assigning ports to different VLANs divides them into separate broadcast domains within the same physical switch, so a broadcast in one VLAN is never seen in another, and traffic between VLANs requires a router or a layer 3 switch. Each port already has its own collision domain, VLAN or not; that is what makes it a switch.
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