Network Distribution Efficiency and Transmission Analysis
Explore the concept of network transmission and distribution efficiency, including factors affecting round-trip times, DNS setup, TCP connections, access delays, and propagation delays. Learn about optimizing data distribution for client-server and P2P networks to enhance performance.
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Presentation Transcript
7 Visiting k of them incurs an RTT of D1 per DNS and visiting each of the remaining incurs an RTT of D2 2RTT0 is required to set up each of the m TCP connections and to request and receive each object
8 k = 2 three DNS server (a) no parallel TCP => ? RTT0 (b) five parallel TCP => ? RTT0
9 (a) The time to transmit an object of size L over a link or rate R is L/R. The average time is the average size of the object divided by R (960,000 bits)/(16,000,000 bits/sec) = 0.06 sec (b)The traffic intensity on the access link is reduced by 60% since the 60% of the requests are satisfied within the institutional network. Thus the average access delay is (0.06 sec)/[1 (0.4)(0.9)] = 0.094 seconds
10 Note that each downloaded object can be completely put into one data packet. Let Tp denote the one-way propagation delay between the client and the server
22 calculating the minimum distribution time for client-server distribution: Dcs= max {NF/us, F/dmin} calculating the minimum distribution time for P2P distribution N = = + D max{F/u , F/d s , NF/(u u )} min s i 2 P P i 1 F = 15 Gbits = 15 * 1024 Mbits us = 30 Mbps dmin = di = 2 Mbps
23 (a) us/N dmin this rate is less than each of the client s download rate (b) us/N dmin the aggregate rate, N dmin, is less than the server s link rate us (c) DCS max {NF/us, F/dmin} + Suppose that us/N dmin + from (a) we have DCS NF/us ----------------------------------------------------------------------------------------------------------------------- DCS= NF/uswhen us/N dmin DCS=F/dminwhen us/N dmin
24 (a) Define u = u1 + u2 + .. + uN. By assumption us<= (us+ u)/N Divide the file into N parts, with the ithpart having size (ui/u)F The server transmits the ithpart to peer i at rate ri= (ui/u)us. Note that r1+ r2+ .. + rN= us
24 (b) Again define u = u1+ u2+ .. + uN. By assumption us>= (us+ u)/N Let ri= ui/(N-1) and rN+1= (us u/(N-1))/N
28 Peer 6 would first send peer 15 a message, saying what will be peer 6 s predecessor and successor?
32 UDPServer determines the client port number by unraveling the datagram it receives from the client.
