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Flow Control Protocols. Prepared By Prof. Anwarul Siddique Anjuman College Of Engg . & Tech. Department Of Computer Science & Engg. Syllabus (Computer Network – 6 th Sem CSE.
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Flow Control Protocols Prepared By Prof. AnwarulSiddique Anjuman College Of Engg. & Tech. Department Of Computer Science & Engg.
Syllabus (Computer Network – 6thSem CSE • Introduction to computer Networks, direction of data flow (simplex,Half duplex, full duplex); Networks: distributed processing, network criteria, physical structure (type of connection, topology), categories of network (LAN, MAN, WAN); Internet: brief history, internet today; Protocols and standards; Reference models: OSI reference model, TCP/IP reference model, their comparative study • Physical Layer: Types of errors, framing (character and bit stuffing), error detection & correction methods; Flow control; Protocols: Stop & wait ARQ, Go-Back- N ARQ, Selective repeat ARQ, HDLC; • Point to point protocol, LCP, NCP, FDDI, token bus, token ring; Reservation, polling, concentration; Multiple access protocols: Pure ALOHA, Slotted ALOHA, CSMA, CSMA/CD, FDMA, TDMA, CDMA; ; Traditional Ethernet, fastEthernet; • Routing : techniques, static vs. dynamic routing , routing table for classfuladdress;Routing algorithms: shortest path algorithm, flooding, distance vector routing, link state routing, Mobile routing basic algorithms. • Protocols: ARP,RARP, IP, ICMP, IPV6; Unicast and multicast routing protocols. Congestion control algorithm: Leaky bucket algorithm, Token bucket algorithm, choke packets. Congestion control protocols • Process to process delivery; UDP; TCP; Quality of service: techniques to improve Qos.ISDN services &ATM; DSL technology, Cable modem, Sonet.Wireless LAN: IEEE 802.11; Introduction to blue-tooth, VLAN’s, Cellular telephony & Satellite network.
Course Outcome After completion of this course students will be able to • explain different types of network topologies and protocols. enumerate and explain the functions of each layers of OSI and TCP/IP Model • identify the types of Error and Error recovery mechanism. • listing and explaining various Data Link layer Protocols like point to point protocol and multiple access protocols. • analyze the concepts of Sub netting, Routing and listing, explain various routing algorithms. • compare and assess various Congestion control protocols and other network layer protocols. • To Assess the various parameters of Quality of Services and explain the concepts of ISDN, ATM reference model, SONET and Bluetooth Technology.
Contents:- • Stop and Wait Protocol • Stop and Wait ARQ
STOP AND WAIT PROTOCOL • Simplest Protocol to achieve flow control. • Very easy to implement and configure. • Based on assumption that channel is error free.
STOP AND WAIT PROTOCOL It states that the sender transmits one frame and then stops, and wait, for the receiver to receive the frame and send back an acknowledgement. This simple delay before transmitting the next frame is an example of flow control. Unless the receiver sends back an acknowledgement, the sender is not allowed to transmit the next frame by the protocol.
STOP AND WAIT PROTOCOL Drawback:- • Very low efficiency of only 17.5 %. • It causes deadlock in case of lost frame and lost acknowledgement.
STOP AND WAIT PROTOCOL Lost Frame:- Sender transmits a frame, but due to transmission error or error in the channel the frame gets damaged or destroyed and is not received by the receiver. This frame is called Lost Frame. It Causes Deadlock because receiver is waiting for frame and the sender is waiting for acknowledgement.
STOP AND WAIT PROTOCOL Lost Acknowledgement :- In this case the frame is received properly by the receiver and the receiver send’s back an acknowledgment but due to channel or transmission errors the acknowledgment gets damaged or destroyed. Again this will result into deadlock.
STOP AND WAIT PROTOCOL ARQ • The problems of Lost Frame and Lost Acknowledgement was solved in Stop and wait ARQ. • The solution was pretty simple, to add a timer at the sender side. • If the sender does not receive the acknowledgement before the timer goes off, the sender will automatically re-transmit the frame.