Sol08 - CHAPTER 8 Switching Solutions to Review Questions...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
1 CHAPTER 8 Switching Solutions to Review Questions and Exercises Review Questions 1. Switching provides a practical solution to the problem of connecting multiple devices in a network. It is more practical than using a bus topology; it is more effi- cient than using a star topology and a central hub. Switches are devices capable of creating temporary connections between two or more devices linked to the switch. 2. The three traditional switching methods are circuit switching , packet switching , and message switching . The most common today are circuit switching and packet switching . 3. There are two approaches to packet switching: datagram approach and virtual- circuit approach . 4. In a circuit-switched network , data are not packetized; data flow is somehow a continuation of bits that travel the same channel during the data transfer phase. In a packet-switched network data are packetized; each packet is somehow an indepen- dent entity with its local or global addressing information. 5. The address field defines the end-to-end (source to destination) addressing. 6. The address field defines the virtual circuit number (local) addressing. 7. In a space-division switch, the path from one device to another is spatially separate from other paths. The inputs and the outputs are connected using a grid of elec- tronic microswitches. In a time-division switch, the inputs are divided in time using TDM. A control unit sends the input to the correct output device. 8. TSI (time-slot interchange) is the most popular technology in a time-division switch. It used random access memory (RAM) with several memory locations. The RAM fills up with incoming data from time slots in the order received. Slots are then sent out in an order based on the decisions of a control unit. 9. In multistage switching, blocking refers to times when one input cannot be con- nected to an output because there is no path available between them—all the possi- ble intermediate switches are occupied. One solution to blocking is to increase the number of intermediate switches based on the Clos criteria.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 10. A packet switch has four components: input ports , output ports , the routing pro- cessor , and the switching fabric . An input port performs the physical and data link functions of the packet switch. The output port performs the same functions as the input port, but in the reverse order. The routing processor performs the function of table lookup in the network layer. The switching fabric is responsible for moving the packet from the input queue to the output queue. Exercises 11. We assume that the setup phase is a two-way communication and the teardown phase is a one-way communication. These two phases are common for all three cases. The delay for these two phases can be calculated as three propagation delays and three transmission delays or 3 [(5000 km)/ (2 × 10 8 m/s)]+ 3 [(1000 bits/1 Mbps)] = 75 ms + 3 ms = 78 ms
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This homework help was uploaded on 04/18/2008 for the course JAVA CDA 4506 taught by Professor Eisler during the Spring '08 term at University of Central Florida.

Page1 / 8

Sol08 - CHAPTER 8 Switching Solutions to Review Questions...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online