2.2 flow control

2.2 flow control

1. Communication
Networks
Flow Control
in Datalink Layer
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2. Overview of Module -2
•Framing
•What is Framing
•Types of Framing
•Methods for identifying the
boundaries
•Flow Control
•What is flow control
•Types of flow control
•Access Control
•What is access control
•Types of access control
•Ethernet –IEEE 802.3
•Evolution of Ethernet
•Frame Format of Ethernet
•Access Control for Ethernet
•Performance Evaluation of Ethernet
•WLAN –IEEE 802.11
•Architecture
•Bluetooth
•WIFI
•Zigbee
•6LowPan
•Network Layer Services
•IPv4
•Packet switching
•Network Layer Protocols
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3. Flow Control -Understanding
HOME
OFFICE
SOURCE
DESTINATION

4. Need for Flow Control
What if the Left Image is Transmitter and the Right Image is Receiver?
Or
Vice Versa
This scenario necessitates the need for Flow Control Mechanism to
regulate the flow of data packets in the network. If not , it leads to
congestion

5. Types of Flow Control Mechanism
•Traditionally four protocols have been defined for the data-
link layer to deal with flow and error control
•Simple Protocol
•Stop and wait Protocol
•Go Back N Protocol
•Selective Repeat Protocol
@ Sliding Window
Protocols
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6. 1. Simple Protocol
•Ourfirstprotocolisasimpleprotocolwithneitherflownorerror
Control.Weassumethatthereceivercanimmediatelyhandleany
frameitreceives.Inotherwords,thereceivercanneverbeover
whelmedwithincomingframes.
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7. 2. Stop and Wait Protocol
•Inthisprotocol,thesender
sendsoneframeatatimeand
waitsforanacknowledgment
beforesendingthenextone.
•Iftheframeisreceived
successfullybythereceiver,an
ACKissenttotheTransmitter.
•Ifframeislost,thentherewill
notbeanyACKfromthe
receiver,sothattheframewill
beretransmitted.
•Iftheframeisreceivedand
ACKsentbythereceiverislost.
Eventhen,theframeis
retransmittedassumingthatthe
frameislost.
Successful transmission of Frame
What if, Frame is Lost or Damaged ?
What if, ACK is Lost or Damaged ?

8. Session Summary
•Flow Control [Similar to traffic control signal]
•Simple Protocol
•Stop and wait protocol
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9. References:
•BehrouzA.Forouzan,―DatacommunicationandNetworking,Fifth
Edition,TataMcGraw–Hill,2013
•LarryL.Peterson,BruceS.Davie,―ComputerNetworks:ASystems
Approach,FifthEdition,MorganKaufmannPublishers,2011.
•FewonlineReferences(WillbeMentionedinthedescriptionSection)
Thank You…