Sliding Window Sliding Window ProtocolsProtocols

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ABHISHEK KUMAR ABHISHEK KUMAR SINGHSINGH

REG. NO. 07RWSCA001REG. NO. 07RWSCA001

Sliding window ProtocolSliding window Protocol

These protocols comes under the These protocols comes under the data link layer.data link layer.

It provides services to the network It provides services to the network layer.layer.

It’s a bidirectional protocol. It means It’s a bidirectional protocol. It means sender deleted the frames when get sender deleted the frames when get the acknowledgment. the acknowledgment.

sendersender receiverreceiver

Purpose Purpose

An incremental Specification.An incremental Specification.

Novel Enhancements to local control Novel Enhancements to local control a soft-state.a soft-state.

Masking the overhead of protocol Masking the overhead of protocol layering.layering.

Types Of WindowsTypes Of Windows

Sender Window.Sender Window.Sender maintains a set of sequence Sender maintains a set of sequence number corresponding to frame it is number corresponding to frame it is permitted to send. These frames are permitted to send. These frames are said to fall within the sending window.said to fall within the sending window.

Receiving Window.Receiving Window.The receiver also maintains a receiving The receiver also maintains a receiving window corresponding to the set of window corresponding to the set of frames, it is permitted to accept.frames, it is permitted to accept.

Types of sliding window Types of sliding window protocolsprotocols

One-Bit sliding window protocols.One-Bit sliding window protocols.

Go Back N sliding window protocols.Go Back N sliding window protocols.

Selective Repeat sliding window Selective Repeat sliding window protocols.protocols.

One-Bit sliding window One-Bit sliding window protocols.protocols.

Sender sends a frame to receiver and Sender sends a frame to receiver and receiver receives that frame and receiver receives that frame and send a new frame and send a new frame and acknowledgment to sender. acknowledgment to sender.

Eg: AEg: A BB A1A1

B1+AckB1+Ack

A2A2

B2+A2 AckB2+A2 Ack

Go Back N sliding window Go Back N sliding window protocols.protocols.

In this the receiver simply discard all subsequent In this the receiver simply discard all subsequent frame, sending no acknowledgment for the frame, sending no acknowledgment for the discarding frame.discarding frame.

sendersender

ReceiverReceiverN=2, it is an error . After 2 the sender didn’t get N=2, it is an error . After 2 the sender didn’t get the acknowledgment. So 3, 4, 5 is discarded and the acknowledgment. So 3, 4, 5 is discarded and then it go back 2.then it go back 2.

0 1 2 3 4 5 2 3 4 5 6 7

0 1 E D D D 2 3 4 5 6 7

Ack 1

Ack

0

Ack 2

Ack 3

Ack 4

Ack 5

Error Discarded

Selective Repeat sliding Selective Repeat sliding window protocols.window protocols.

In this a bad frame that is received is discarded, but good In this a bad frame that is received is discarded, but good frame received after it are buffered. When the sender times frame received after it are buffered. When the sender times out, only the oldest unacknowledged frame is out, only the oldest unacknowledged frame is retransmitted. Eg:retransmitted. Eg:

sender sender

ReceiverReceiver

0 1 2 3 4 5 2 6 7 8 9 10

0 1 E 3 4 5 2 6 7 8 9 10

Ack 1

Ack

0

Ack 2

Ack 3

Ack 4

Ack 5

ErrorAck

6

Ack 7

Ack 8

THANKS…..THANKS…..