TCS Papers: Sample Questions 195 - 196 of 502

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Question number: 195

» Basic CS » Networks

Essay Question▾

Describe in Detail

What is subnet?


  • It is a section of a large networks usually separated by a bridge or router. It is an identifiably separate part of a network.

  • Typically, a subnet represents all the machines at one geographic location, in one building, or on the same local area network (LAN).

  • Network divided into subnets allows connecting to Internet with a single shared network address. Without subnets, an organization could need multiple connections to the Internet, one for each of its physically separate sub networks. Internet routing tables on gateways outside the organization would need to know and manage routing that should be handled within an organization.

 Image shows the subnet

Image Shows the Subnet

Given the image s define the subnet

Question number: 196

» Basic CS » Networks

Essay Question▾

Describe in Detail

What is usage of sequence number in reliable transmission?


  • Frames are numbered using sequence numbers field in data frame.

  • To minimize the frame size, sequence numbers have smallest range to provide unambiguous communication and hence can wrap around.

  • TCP uses a 32-bit sequence number that counts bytes in the data stream.

  • Each TCP packet contains the starting sequence number of the data in that packet, and the sequence number (called the acknowledgment number) of the last byte received from the remote peer.

  • Each TCP peer must track both its own sequence and that of remote peer.

What is the use of flags in networking?

  • TCP uses a number of control flags to manage the connection- some pertain to single packet, but two flags (SYN and FIN), require reliable delivery as they mark the beginning and end of the data stream. To insure their reliable delivery they are assigned spots in the sequence number space.

  • Each flag occupies a single byte.