Basic CS [TCS Placement]: Sample Questions 134 - 135 of 196

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Question 134

Basic CS
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Describe in Detail

Essay▾

What are the responsibilities of Data Link Layer?

Explanation

The Data Link Layer transforms the physical layer, a raw transmission facility, to a reliable link and is responsible for node-node delivery. It provides following functions:

  • Framing
    • Frames are streams of bits received from the network layer broken into manageable data units.
    • This division of stream of bits is done by Data Link Layer.
  • Physical Addressing

    The Data Link layer adds a header to the frame that defines physical address of the sender or receiver of the frame, if the frames are to be distributed to different systems on the network.

  • Flow Control
    • Provides a flow control mechanism to avoid a fast transmitter from running a slow receiver by buffering the extra bit.
    • Prevents overflow at the receiver side.
  • Error Control
    • Adds a trailer at the end of the frame for error control.
    • Also, duplication of frames is prevented by using this mechanism.
  • Access Control

    Protocols of this layer determine the devices that can control the link at any given time- when two or more devices are connected to the same link.

Question 135

Basic CS
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Describe in Detail

Essay▾

What is BGP (Border Gateway Protocol) ?

Explanation

  • Border gateway protocol is an inter-autonomous system routing protocol to advertise reachable networks within an autonomous system.
  • Enables information to be shared with the autonomous system- exchange network reachability information with other BGP systems.
  • Newer than EGP (Exterior Gateway Protocol) .
  • Manages packets routed across the internet through the exchange of routing and reachability information between edge routers. Routes packets between autonomous systems (AS) under one service provider.
  • Traffic routed within a single network AS is referred to as internal BGP, or iBGP.
  • BGP connecting one AS to other AS is referred as external BGP, or eBGP.
  • BGP rule is that an AS advertises only those routes that it uses.
  • BGP runs over a reliable transport protocol and uses TCP port for establishing its connections.
The Border Gateway Protocol (BGP)

Developed by: