Nwhat sense is it now possible for a country to be ""occupied"" by an invisible invader that arrives through airwaves and wireless networks? a. it is almost impossible to block foreign countries’ satellite broadcasts and internet transmissions. b. spy satellites and other communications technology are increasingly advanced. c. global positioning systems have allowed detailed mapping of previously inaccessible places. d. the u. s. government can eavesdrop on almost any form of modern communication.

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?

Which component acts as a platform on which application software runs

Http is the protocol that governs communications between web servers and web clients (i.e. browsers). part of the protocol includes a status code returned by the server to tell the browser the status of its most recent page request. some of the codes and their meanings are listed below: 200, ok (fulfilled)403, forbidden404, not found500, server errorgiven an int variable status, write a switch statement that prints out the appropriate label from the above list based on status.