Provides access to the Internet; may also be internal

Consider a slotted aloha system, where the time slot equals the fixed duration of each packet. assume that there are 4 stations a, b,c, d sharing the medium. (a) stations a, b,c, d receive one packet each from higher layers at times 1.3, 1.5, 2.6,5.7 respectively. show which transmissions take place when, according to the slottedaloha protocol; describe all transmissions until all four packets have been successful. when needed, each station has access to the following sequence of random number, provided by a random number generator and drawn uniformly between 0 and 1: (1) station a draws numbers: 0.31, 0.27, 0.78, 0.9, 0.9, 0.11, 0. (2) station b draws numbers: 0.45, 0.28, 0.11, 0.83, 0.37, 0.22, 0. (3)station c draws numbers: 0.1, 0.2, 0.3, 0.4, 0. (4) station d draws numbers: 0.36, 0.77, 0.9, 0.1, 0.1, 0.1, 0.1, 0. (b) in slotted aloha, a station transmits in each time slot with a given probability. what probabilities would you assign to each of the four stations so as to: (i) maximize the efficiency of the protocol? (ii) maximize fairness among the four stations? (c) will the efficiency increase or decrease if we modify slotted aloha as follows: (i) get rid of slots and allow stations to transmit immediately? (ii) implement carrier sensing? (iii) implement collision detection? (iv) implement collision avoidance?

Word vocabulary words: print, proofread, status line, graphics, font effects, left margin, justification, line spacing, copy/paste, data. review words: font point, bold, save, center, error. fill in the correct word for the definition and then transfer the letters to the appropriate spot by number. some numbers will be found multiple times. you will end up with a quotation about…… what else? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 k 16 17 18 19 20 21 22 23 24 25 8 27 28 29 w 31 32 k 34 35 36 w h 39 40 41 42 8 44 45 46 47 48 49 50 51 52 53 54 55 .1. a software function that records keystrokes on a disk or drive so information can be 5 4 52 9 later retrieved. p n 2. to produce a paper copy of information. 10 7 12u n 3. a display that shows the location of the cursor, pages, etc. 45 46 18 27 36 20 42p4. pictures or images, located in clip art or other files. 6 24 44 28 34 49 555. any mis-stroke of a key. 47 41 48 2 10 n6. allows major changes to the font such as shadow, emboss, etc. 21 25 46 35 23 21 29 14 22 17 n7. a feature that centers lines of text horizontally. 49 53 46 9 51 p8. size of the font 31 16 22 b l 9. a feature that prints designated text darker than the rest to add emphasis. 32 3 . p10. to compare copy on a display screen or printout to the original 24 39 25 23 54 9 50 3 and correct errors. j un 11. a feature that allows text to be aligned at the left 11 12 7 21 16 49 40 46 34 2 and right margins. leftn 12. amount of blank space on the left side of the paper. 8 18 41 6 34 linen 13. number of blank lines between lines of text. 17 4 49 13 1914. any information inputted into the computer. 3 4 46 44 p /p15. feature that duplicates text from one location and places it in another.

What is a point-in-time measurement of system performance?