EECS 563 Test 1 Fall 2006 E T 1 X 1 PB 1 N 1 N 1 Average Arrival Rate Average Service Rate X Average Service Time Name Student Number Be sure and clearly mark your final answer 5 pts 1 What is the difference between a WAN and LAN 2 Information from ground station A is sent to a geosynchronous satellite 35 782 km above the earth the satellite sends the information on to ground station B The link rate is 100 Mb s and the packet size is 1000 bits Speed of light is 3x108m s 10 pts a What is the end to end delay between station A and B for one packet if virtual circuit packet switching is used 10 pts b What is the end to end delay between station A and B for one packet if datagram packet switching is used 1 5 pts 3 The link layer is responsible for end to end connections True or False Circle the correct answer 4 At the source a 2kByte message is passed to the transport layer TCP which adds 20 Bytes of transport layer protocol information TPI this packet is passed to the network layer IP which adds 20 Bytes of network protocol information NPI this packet is passed to the link layer High Level Link Control HDLC with adds 6 bytes of link layer protocol information LPI to create a frame that is transported across the physical layer 5 pts a What of the transported bits is used by the system to perform protocol processing functions 5 pts b What is a major use of the network protocol information NPI 5 pts c What is the size of the packet that is passed to destination transport layer for processing 5 A PBX is connected to the PSTN by N lines Given i 50 phones are connected to the PBX where during the busy hour each phone makes 2 calls lasting 5 min on average and ii a QoS requirement of a probability of blocking 1 5 pts a What is the load in Erlangs 5 pts b Find N 2 5 pts 6 MP3 is part of the Moving Pictures Expert Group set of standards True or False Circle the correct answer 7 Memory is inexpensive so assume the output port on the routers below have large buffers Router A Router B The network managers have determined that the load on the A B link is 0 50 with a corresponding delay of 1 ms The average packet size on the A B link is 1000 bits 10 pts a What is the capacity of the A B link 5 pts b Using the traffic parameters i e arrival rate and message length from part a determine the required capacity to reduce the delay to 0 20ms 3 8 In many voice TDM systems the frame size is fixed at 125us For this problem use a frame size of 125us 5 pts a If 96 voice channels are supported what is the slot time 5 pts b If each voice sample is encoded to 4 bits sample what is the bit time 5 pts c For the parameters in parts a and b what is the bit rate of this TDM signal 10 pts 9 Specify the key components in the trade off between the size of the jitter buffer and voice quality in VoIP systems Then discuss the trade off between the size of the jitter buffer and voice quality in VoIP systems 4 Erlang B Traffic Table Maximum Offered Load Versus B and N B is in 0 1 0 5 1 0 2 5 N B 0 01 0 05 10 15 20 30 1 2 3 4 5 0001 0142 0868 2347 4520 0005 0321 1517 3624 6486 0010 0458 1938 4393 7621 0050 1054 3490 7012 1 132 0101 1526 4555 8694 1 361 0204 2235 6022 1 092 1 657 0526 3813 8994 1 525 2 219 1111 5954 1 271 2 045 2 881 1765 7962 1 603 2 501 3 454 2500 1 000 1 930 2 945 4 010 4286 1 449 2 633 3 891 5 189 6 7 8 9 10 7282 1 054 1 422 1 826 2 260 9957 1 392 1 830 2 302 2 803 1 146 1 579 2 051 2 558 3 092 1 622 2 158 2 730 3 333 3 961 1 909 2 501 3 128 3 783 4 461 2 276 2 935 3 627 4 345 5 084 2 960 3 738 4 543 5 370 6 216 3 758 4 666 5 597 6 546 7 511 4 445 5 461 6 498 7 551 8 616 5 109 6 230 7 369 8 522 9 685 6 514 7 856 9 213 10 58 11 95 11 12 13 14 15 2 722 3 207 3 713 4 239 4 781 3 329 3 878 4 447 5 032 5 634 3 651 4 231 4 831 5 446 6 077 4 610 5 279 5 964 6 663 7 376 5 160 5 876 6 607 7 352 8 108 5 842 6 615 7 402 8 200 9 010 7 076 7 950 8 835 9 730 10 63 8 487 9 474 10 47 11 47 12 48 9 691 10 78 11 87 12 97 14 07 10 86 12 04 13 22 14 41 15 61 13 33 14 72 16 11 17 50 18 90 16 17 18 19 20 5 339 5 911 6 496 7 093 7 701 6 250 6 878 7 519 8 170 8 831 6 722 7 378 8 046 8 724 9 412 8 100 8 834 9 578 10 33 11 09 8 875 9 652 10 44 11 23 12 03 9 828 10 66 11 49 12 33 13 18 11 54 12 46 13 39 14 32 15 25 13 50 14 52 15 55 16 58 17 61 15 18 16 29 17 41 18 53 19 65 16 81 18 01 19 22 20 42 21 64 20 30 21 70 23 10 24 51 25 92 21 22 23 24 25 8 319 8 946 9 583 10 23 10 88 9 501 10 18 10 87 11 56 12 26 10 11 10 81 11 52 12 24 12 97 11 86 12 64 13 42 14 20 15 00 12 84 13 65 14 47 15 30 16 13 14 04 14 90 15 76 16 63 17 51 16 19 17 13 18 08 19 03 19 99 18 65 19 69 20 74 21 78 22 83 20 77 21 90 23 03 24 16 25 30 22 85 24 06 25 28 26 50 27 72 27 33 28 74 30 15 31 56 32 97 26 27 28 29 30 11 54 12 21 12 88 13 56 14 25 12 97 13 69 14 41 15 13 15 86 13 70 14 44 15 18 15 93 16 68 15 80 16 60 …