1. C. Protocol Data Units are used to define data at each layer of the OSI model. PDUs at the Network
layer are called packets.
2. A, D. An Ethernet frame has source and destination MAC addresses, an Ether-Type field to identify the Network layer protocol, the data, and the FCS field that holds the result of the CRC.
3. C. 802.11b, also called “Wi-Fi,” has a maximum data rate of 11Mbps.
4. D. The Transport layer receives large data streams from the upper layers and breaks these up into smaller pieces called segments.
5. A, C, E, G. Routers provide packet switching, packet filtering, internetwork communication, and path selection.
6. B. The only layer of the OSI model that can change data is the Presentation layer.
7. C. The encapsulation method is: data, segment, packet, frame, bit.
8. A, D. The main advantage of a layered model is that it can allow application developers to change aspects of a program in just one layer of the layer model’s specifications. Advantages of using the OSI layered model include, but are not limited to, the following: It divides the network
communication process into smaller and simpler components, thus aiding component development, design, and troubleshooting; allows multiple-vendor development through standardization of network components; encourages industry standardization by defining what functions
occur at each layer of the model; allows various types of network hardware and software to communicate; and prevents changes in one layer from affecting other layers, so it does not hamper development.
9. B, C. Bridges break up collision domains, which allows more bandwidth for users.
10. A, D. Unlike full duplex, half-duplex Ethernet operates in a shared collision domain, and it has a lower effective throughput then full duplex.
11. D. Fiber optic cable provides a more secure, long-distance cable that is not susceptible to EMI interference at high speeds.
12. C. A reliable Transport layer connection uses acknowledgments to make sure all data is transmitted and received reliably. A reliable connection is defined by a virtual circuit that uses acknowledgments, sequencing, and flow control, which are characteristics of the Transport
layer (layer 4).
13. A, C, D. The common types of flow control are buffering, windowing, and congestion avoidance.
14. B, C, E. Hubs cannot run full-duplex Ethernet. Full duplex must be used on a point-to-point connection between two devices capable of running full duplex. Switches and hosts can run full duplex between each other.
15. C, D. A MAC address is 6 bytes long (48 bits) and is burned into the NIC card by the manufacturer. IPX, when it was still used, used the MAC address as part of the configuration.
16. B, C, D, F, G, H. Although Bill Gates is a good answer for me, the answers are: not enough bandwidth, too many users, broadcast storms, multicasting, adding hubs for connectivity to the network, and a large amount of ARP or IPX traffic.
17. B, D. Routers, by default, break up broadcast domains, which means that broadcasts sent on one network would not be forwarded to another network by the router.
18. C. Once transmitting stations on an Ethernet segment hear a collision, they send an extended jam signal to ensure that all stations recognize the collision. After the jamming is complete, each sender waits a predetermined amount of time, plus a random time. After both timers expire, they are free to transmit.
19. B, C. No collision on a point-to-point full-duplex Ethernet segment should occur, and fullduplex Ethernet should be faster then half-duplex Ethernet.
20. C. The first three bytes of a hardware (MAC) address are considered the OUI portion and identify the manufacturer of the card. This code, which is assigned by the IEEE, is called the organizationally unique identifier (OUI). The first three bytes are C9-3F-32, which is 11001001-00111111-00110010 in binary.
0 comments:
Post a Comment