This elementary problem begins to explore propagation delay and transmis- sion delay, two central concepts in data networking. Consider two hosts, A and B, connected by a single link of rate R bps. Suppose that the two hosts are separated by m meters, and suppose the propagation speed along the link is s meters/sec. Host A is to send a packet of size L bits to Host B a. Express the propagation delay, dprops in terms of m and s

b. Determine the transmission time of the packet, drans, in terms of L and R.

c. Ignoring processing and queuing delays, obtain an expression for the end-

d. Suppose Host A begins to transmit the packet at time t = 0. At time t = dtrans'

e. Suppose drop is greater than dran . At time t = d, ans, where is the first bit of

f. Suppose dprop is less than dtrans. At time t = dtrans, where is the first bit of

g. Suppose s = 2.5-108, L = 120 bits, and R = 56 kbps. Find the distance m so that dprop equals drans

7.23 main lab 7 - online shopping cart background this main lab extends the earlier prep lab "online shopping cart part 1". (you should save this as a separate project from the earlier prep lab). you will create an on-line shopping cart like you might use for your on-line purchases. the goal is to become comfortable with setting up classes and using objects. requirements this lab can be done individually or as pair programming. expanded itemtopurchase class (15 points) extend the itemtopurchase class as follows. we will not do unit testing in this lab so we will not be giving you the names of the member functions. create good ones on your own. create a parameterized constructor to assign item name, item description, item price, and item quantity (default values of "none" for name and description, and 0 for price and quantity). additional public member functions set an item description get an item description print the cost of an item - outputs the item name followed by the quantity, price, and subtotal (see example) print the description of an item - outputs the item name and description (see example) additional private data members a string for the description of the item. example output of the function which prints the cost of an item: bottled water 10 @ $1.50 = $15.00 example output of the function which prints the item description: