ImPorTanT NetWorkIng QuEstiOnS Part4.

61. What is 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.

62. What is terminal emulation, in which layer it comes

Telnet is also called as terminal emulation. It belongs to application layer.

63. What is frame relay, in which layer it comes

Frame relay is a packet switching technology. It will operate in the data link layer.

64. 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"

65. What is SAP

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

66. What is subnet

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

67. What is Brouter

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

68. 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.

69. What are the different type of networking / inter networking devices

Repeater:

Also called a re generator, it is an electronic device that operates only at physical layer. It receives the signal in the

network before it becomes weak, regenerates the original bit pattern and puts the refreshed copy back in to the link.

Bridges:

These operate both in the physical and data link layers of LANs of same type. They divide a larger network in to smaller

segments. They contain logic that allow them to keep the traffic for each segment separate and thus are repeaters that relay a frame only the side of the segment containing the intended recipent and control congestion.

Routers:

They relay packets among multiple interconnected networks (i.e. LANs of different type). They operate in the physical,

data link and network layers. They contain software that enable them to determine which of the several possible paths is the best for a particular transmission.

Gateways:

They relay packets among networks that have different protocols (e.g. between a LAN and a WAN). They accept a

packet formatted for one protocol and convert it to a packet formatted for another protocol before forwarding it. They operate in all seven layers of the OSI model.

70. What is mesh network

A network in which there are multiple network links between computers to provide multiple paths for data to travel.

71. What is passive topology

When the computers on the network simply listen and receive the signal, they are referred to as passive because they don’t amplify the signal in any way. Example for passive topology - linear bus.

72. What are the important topologies for networks

BUS topology:

In this each computer is directly connected to primary network cable in a single line.

Advantages:

Inexpensive, easy to install, simple to understand, easy to extend.

STAR topology:

In this all computers are connected using a central hub.

Advantages:

Can be inexpensive, easy to install and reconfigure and easy to trouble shoot physical problems.

RING topology:

In this all computers are connected in loop.

Advantages:

All computers have equal access to network media, installation can be simple, and signal does not degrade as much as in other topologies because each computer regenerates it.

73. What are major types of networks and explain

Server-based network

Peer-to-peer network

Peer-to-peer network computers can act as both servers sharing resources and as clients using the resources.

Server-based networks provide centralized control of network resources and rely on server computers to provide security and network administration

74. What is Protocol Data Unit

The data unit in the LLC level is called the protocol data unit (PDU). The PDU contains of four fields a destination service access point (DSAP), a source service access point (SSAP), a control field and an information field. DSAP, SSAP are addresses used by the LLC to identify the protocol stacks on the receiving and sending machines that are generating and using the data. The control field specifies whether the PDU frame is a information frame (I -

frame) or a supervisory frame (S - frame) or a unnumbered frame (U - frame).

75. What is difference between baseband and broadband transmission

In a baseband transmission, the entire bandwidth of the cable is consumed by a single signal. In broadband transmission, signals are sent on multiple frequencies, allowing multiple signals to be sent simultaneously.

76. What are the possible ways of data exchange

(i) Simplex (ii) Half-duplex (iii) Full-duplex.

77. What are the types of Transmission media

Signals are usually transmitted over some transmission media that are broadly classified in to two categories.

Guided Media:

These are those that provide a conduit from one device to another that include twisted-pair, coaxial cable and fiber-optic cable. A signal traveling along any of these media is directed and is contained by the physical limits of the medium. Twisted-pair and coaxial cable use metallic that accept and transport signals in the form of electrical current. Optical fiber is a glass or plastic cable that accepts and transports signals in the form of light.

Unguided Media:

This is the wireless media that transport electromagnetic waves without using a physical conductor. Signals are broadcast either through air. This is done through radio

communication, satellite communication and cellular telephony.

 

78. Difference between the communication and transmission.

Transmission is a physical movement of information and concern issues like bit polarity, synchronization, clock etc.

Communication means the meaning full exchange of information between two communication media.

79.The Internet Control Message Protocol occurs at what layer of the seven layer model?

Network

80.Which protocol resolves an IP address to a MAC address?

ARP

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