Both bus and tree topologies are characterized by the use of multipoint (1). For the bus, all stations attach, through appropriate hardware (2)known as a tap, directly to alinear transmission medium, or bus. Full-duplex operation between the station and the tap allowsdata to be transmitted onto the bus and received from the (3). A transmission from anystation propagates the length of the medium in both directions and can be received by all other(4). At each end of the bus is a (5), which absorbs any signal, removing it from thebus. (3)是()
A. tree
B. bus
C. star
D. ring
The presentation layer is concerned with the(1) and semantics of the information exchanged between two systems. The processes in two systems are usually exchanginginformation in the form of character(2)numbers, and so on. The information should bechanged to bit(3) before being transmitted. Because different encoding systems, thepresentation layer is responsible for (4)between these different encoding methods. Thepresentation layer at the sender changes the information from its sender-dependent format into acommon format. The presentation layer at the receiving machine changes the common format intoits(5) dependent format. (4)是()
A. capability
B. interoperability
C. reliability
D. dependability
The European online fashion business is fierce. Just ask backers of one-time highfliers. Like boo. corn, the urban sportswear retailer that tanked last year, and dressmart, corn, the struggling men’s wear specialist. Those once stellar online brands expanded too fast, spent much more than they earned, and then lost their investor support after Internet stocks began plummeting last April. The markets sent online fashion stores a tough message: come up with business models that generate revenues. A few firms have shown that not all online fashion shops are Internet disasters. Copenhagen- based haburi, corn, the online designer-label discount store, Sweden’s sportswear vendor Sportus and the Italian shirts store Marco Bracci are doing well in a very tough environment. Haburi’s distinctive business model is an Internet version of the factory outlet where brand manufacturers sell directly to consumers at lower prices from huge out-of-town shopping malls. A concept used in the U. S. far more than in Europe, and Haburi wants to fill the gap. Michael Vad, Haburi’s CEO, says that Europe’s apparel factory outlet sector could yield $10 billion in sales annually. According to Vad, national regulations that limit malls outside centers have hampered the development of this sector. "For the consumer, there is the two-hour drive to the mall, and when you get there, you don’t know whether you will get the size or color you want," says Vad. By going online, Haburi aims to cut the retailer’s costs, save consumers the long drive, and" deliver orders within two or five days. Haburi splits net revenue 50-50 with the brand manufacturers. Apparel is difficult to sell online because people like to feel and touch the clothes they buy. For the online retailer, acquiring the items, inspecting them, cleaning and storing them can be expensive. "The cost of customer service in the apparel business is much higher than selling books or even furniture," says Matthew Nordan, a retail analyst at Forester Research’s Amsterdam office. Unless linked to a major established operation, an online retailer needs a competitive edge. For example, Italian shirt-maker Marco Bracci sells expensive goods for high profits and has cornered a niche market. Dressmart, on the other hand, tired to do too much too soon. Originally it planned to sell only shirts and to make the original Swedish operation profitable before branching out. But within months it tried to go pan-European and sell everything including ties, shoes and sportswear, and to rent physical outlet at airports. Dressmart, on the verge of bankruptcy and searching for a backer, has now scaled back and operate only in Sweden. What is the best title for the passage
Apparel Online Stores.
B. Online Business vs. Traditional Business.
C. Ups and Downs of Online Business.
D. The Future of Online Stores.
A transport layer protocol has several responsibilities, One is to create a process-to-process (program-to-program) communication; TCP uses port (1) to accomplish this. Anotherresponsibility of a transport layer protocol is to create a(2)and error-control mechanism atthe transport level. TCP uses a sliding(3)protocol to achieve flow control. It uses theacknowledgment packet, time-out, and retransmission to achieve (4) control. The transportlayer is also responsible for providing a connection mechanism for the application program. Theapplication program sends (5)of data to the transport layer. It is the responsibility of thetransport layer at the sending station to make a connection with the receiver. (4)是()
A. packet
B. time
C. error
D. phase