17. Data word generator codeword Data word Checker Codeword SENDER RECEIVER Encoder Decoder Extract Discard Unreliable Transmission Data words Codewords Code fro error detection protocol stack 00 000 01 011 10 101 11 110
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20. Simplest protocol sender site algorithm While (true) { wait for event(); if(event ( request to send)) { get data(); make frame(); send frame(); } } protocol stack
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22. STOP AND WAIT PROTOCOL While(true) Can send= true { wait for event(); if( event(request to send)and can send) { get data(); make frame(); send frame(); can send= false; } Wait for event(); If ( event( arrival notification) { receive frame(); can send= true; } } protocol stack
29. Network layer protocols Internet protocol : Responsible for network layer addressing. IP address: An address assigned to every interface. They are of two types: IPV4 and IPV6 protocol stack
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31. IPV4 data packet format protocol stack 32bits version Header length Type of service Data packet length 16-bit identifier Flags 13-bit fragmentation offset Time-to-live Upper-layer protocol Header checksum 32-bit source IP address 32-bit destination IP address Options(if any) Data
42. Comparison Between UDP and TCP protocol stack UDP TCP Packet Header Size 8 bytes 20 – 60 bytes Transport Layer Packet entity Datagram Segment Port Numbering Yes Yes Error Detection Optional Yes Reliability: Error recovery by automatic repeat request (ARQ) No Yes Virtual circuits: Sequence numbering and reordering No Yes Flow control No Yes Congestion avoidance: Variable congestion window, slow start, time outs No Yes Multiple streams No No ECN support No Yes