Business Data Communications and Networking 7th Edition Test Bank - Chapter 05

Business Data Communications and Networking 7th Edition Test Bank - Chapter 05 (400 Level Course)

TRUE/FALSE

The following are possible True/False questions for tests. The statement is given and the answer is provided in square brackets. The level of difficulty (easy, moderate, difficult) and the page number(s) relevant to the topic are also furnished.

1. Several different protocols exist that specify how network and/or transport layer packets are organized. [True; p. 136]
Easy

2. TCP/IP is a data link protocol that is used on the Internet. [False, it is a network and transport layer set of standards; p. 136]
Moderate

3. The network layer sits between the application layer and the data link layer in the Internet five-layer network model. [False, it is between the transport layer and the data link layer; p. 136]
Easy

4. The network layer is responsible for the end-to-end delivery of the message. [False, it is the responsibility of the transport layer; p. 136]
Easy

5. The network layer depends upon the data link layer for error-free delivery of messages from one computer to the next. [True; p. 136]
Easy

6. Software with multiprotocol stacks refers to the fact that the software supports several different transport/network protocols. [True; p. 138]
Easy

7. Some network protocols, such as TCP/IP, are compatible with a variety of different data link layer protocols, such as Ethernet or frame relay. [True; p. 138]
Easy

8. SNA was originally designed to provide an end-to-end solution for Compaq customers using entirely Compaq or Compaq-compatible hardware and software. [False, it was developed by IBM; p. 138]
Moderate

9. TCP/IP stands for Transmission Control Protocol/Internet Protocol. [True; p. 138]
Easy

10. The IP portion of TCP/IP performs a packetizing function. [False, TCP packetizes; p. 138]
Easy

11. The TCP portion of TCP/IP performs a data presentation/formatting function. [False, it packetizes; p. 138]
Easy

12. The TCP header contains the source and destination port identifiers. [True; p. 139]
Easy

13. TCP includes a sequence number so that the packets can be reassembled at the destination in the correct order. [True; p. 139]
Easy

14. The newer version of IP increases the address size from 32 bits to 128 bits. [True; p. 139]
Easy

15. IPX/SPX is the primary network protocol uses by Microsoft networks. [False, it is used primarily by Novell networks; p. 140]
Moderate

16. X.25 is primarily used in local area networks. [False, it is a wide area network standard; p. 140]
Moderate

17. SNA is the protocol of the future. [False, it will probably disappear over time because it is a proprietary standard developed by IBM; p. 140]
Moderate

18. To help determine to which application a transmission should be delivered on a particular computer, TCP uses the application layer port addresses to distinguish among many open applications on a computer. [True; p. 141]
Moderate

19. Because there is a limit on the length of a frame that the data link layer can transmit from node to node, the transport layer breaks up the message from the application layer into several smaller packets. [True; p. 141]
Moderate

20. Connectionless routing sets up a TCP connection, or virtual circuit between a sender and receiver. [False, that is done with connection-oriented routing; p. 142]
Moderate

21. TCP/IP operates only as connection-oriented. [False, TCP/IP can operate as either connectionless or connection-oriented; p. 143]
Moderate

22. RSVP, a type of Quality of Service protocol, can be used for audio/video streaming applications. [True; p. 143]
Moderate

23. An example of an application layer address is www.indiana.edu. [True; p. 144]
Easy

24. The network layer address for IP is ten bytes long when using IPv4. [False, it is four bytes long; p. 144]
Easy

25. The data link layer address is generally encoded in a network card by the card’s manufacturer. [True; p. 145]
Easy

26. ICANN is the acronym for the organization that manages the assignment of IP addresses and application layer addresses. [True; p. 145]
Moderate

27. IPv4 addresses offer unlimited opportunity for expansion and growth on the Internet. [False, with IPv4, the Internet is quickly running out of addresses; p. 146]
Easy

28. Partial bytes cannot be used as subnets. [False, any portion of the IP address can be designated as a subnet; p. 147]
Moderate

29. Subnet masks tell computers what part of an IP address is to be used to determine whether a destination is in the same subnet or in a different subnet. [True; p. 147]
Moderate

30. Two standards for dynamic addressing for TCP/IP networks are: Bootstrap Protocol and Dynamic Host Control Protocol. [True; p. 147]

31. Dynamic routing requires less processing by each computer in the network. [False, it requires more processing; p. 155]
Easy

32. Part of the function of address resolution is translating the application layer address of the destination into a network layer address. [True; p. 148]
Easy

33. Domain Name Servers provide the equivalent of directory assistance for application layer addresses. [True; p. 148]
Easy

34. An Address Resolution Protocol message is broadcast to all computers in a subnet to find the data link layer address. [True; p. 150-151]
Moderate

35. Routing is the process of determining the path or route through the network that a particular message will follow from the sender to the recipient. [True; p. 152]
Easy

36. There are four fundamental approaches to routing: centralized, static routing, dynamic routing, and monitor routing. [False, centralized, static routing, and dynamic routing are the 3 approaches; p. 154]
Moderate

37. When using dynamic routing, routing decisions are always made by a central host or server. [False, the decisions are made in a decentralized manner; p. 154]
Easy

38. A hop in a routing calculation is defined as one link or circuit. [True; p. 154]
Easy

39. An autonomous system is a network operated by one organization. [True; p. 155]
Easy

40. A routing protocol used inside an autonomous system is called an exterior routing protocol. [False, it is an interior routing protocol; p. 155]
Easy

41. Enhanced Interior Gateway Routing Protocol is a dynamic link state interior routing protocol developed by Cisco. [True; p. 158]
Moderate

42. A multicast message can be used to send a message to a maximum of two other computers. [False, it is used to send a message to a group of computers; p. 158]
Easy

43. The newest version of HTTP permits Web browsers to leave the connection open for the first and subsequent HTTP requests to the same server. [True; p. 164]
Moderate

MULTIPLE CHOICE

The following are possible multiple-choice questions for tests. The question is posed and the answer is provided under the choices. The level of difficulty (easy, moderate, difficult) and the relevant page number(s) for the topic are also furnished.

1. __________ is not an important function of the transport layer.
a. end-to-end delivery of the message
b. taking messages from the application layer
c. routing
d. breaking long messages into smaller packets
e. interfacing with the network layer
Answer: c, Moderate, p. 136-137

2. Network _______ are important to ensure that hardware and software from different vendors operated by different companies can communicate.
a. protocols
b. directories
c. frequencies
d. topologies
e. directions
Answer: a, Easy, p. 136

3. _______ is the dominant network protocol today.
a. SDLC
b. SNA
c. IPX/SPX
d. TCP/IP
e. X.25
Answer: d, Easy, p. 136

4. Transmission Control Protocol/Internet Protocol was developed for ________ in 1974.
a. ARPANET
b. IBM
c. Hewlett-Packard
d. University of Minnesota
e. Xerox
Answer: a, Easy, p. 138

5. TCP/IP:
a. is the least commonly used network protocol for LANs because it cannot be combined with Ethernet
b. performs packetizing, as well as routing and addressing functions
c. is not very efficient and is prone to errors
d. is compatible with only one type of data link protocol, SDLC
e. refers to Telephone Control Procedures/Inter-exchange Procedures
Answer: b, Moderate, p. 138-140

6. A typical TCP packet has a _______ header of control information.
a. 32-bit
b. 64-bit
c. 160-bit
d. 192-bit
e. 32-byte
Answer: d, Easy, p. 139

7. The older version of IP has a ________ header of control information.
a. 128-bit
b. 192-bit
c. 1024-bit
d. 160-bit
e. 320-bit
Answer: b, Easy, p. 139

8. IP:
a. performs packetizing functions
b. does not have a header
c. is currently in use with only one packet form or structure
d. performs routing functions
e. performs error control functions
Answer: d, Moderate, p. 139

9. The newer form of IP, version 6 (Ipv6) is:
a. running out of address space to support the growth of the Internet
b. has a 20 byte header
c. has an increased address size from 32 bits to 128 bits
d. does not include version number in its header
e. does not include hop limit in its header
Answer: c, Difficult, p. 139

10. IPX/SPX:
a. refers to Intermodulation Protocol Exchange/Serial Protocol Exchange
b. is the primary network protocol used by Microsoft NT networks
c. is based on a routing protocol developed by IBM in the 1990s
d. is not similar to TCP/IP in function can not be used with Ethernet
e. performs packetizing, as well as addressing and routing functions
Answer: e, Moderate, p. 140

11. X.25:
a. does not perform routing functions
b. is a network standard used in wide area networks
c. is extensively used in North America by domestic (non-international) companies
d. is relatively new, therefore it is not used by many organizations
e. has one part that handles addressing and packetizing
Answer: b, Moderate, p. 140

12. SNA:
a. is a protocol that makes it easy to integrate SNA networks with other networks that use other industry standard protocols, such as TCP/IP
b. was developed by Amdahl in 1988
c. refers to Synchronous Novell Architecture
d. is a proprietary non-standard network protocol
e. was developed originally for client-server network models
Answer: d, Moderate, p. 140
13. Assume that more than one application programs that are using the same communications line on a particular computer. To be able to decide to which application program a message should be delivered on this computer, TCP/IP relies on the:
a. data link layer address
b. port address
c. application layer address
d. network address
e. IP address
Answer: b, Moderate, p. 141

14. The transport layer must break messages from the application layer into several _____ that can be sent to the data link layer.
a. bits
b. bytes
c. frames
d. packets
e. strings
Answer: d, Easy, p. 141-142

15. The negotiation by the transport layer at the sender with the transport layer at the receiver to determine what size packets should be set up is done via establishing a(n) ___________ between the sender and receiver.
a. network layer address resolution
b. one way handshake
c. SNA message
d. TCP connection
e. DNS server request
Answer: d, Moderate, p. 142

16. A virtual circuit is established in the ___________ routing method.
a. asynchronous
b. connection-oriented
c. frequency division
d. application net
e. connectionless
Answer: b, Moderate, p. 142

17. _____________ routing is a method of routing in which each packet makes its own way through the network.
a. Frequency division
b. Connection-oriented
c. PCMCIA
d. Connectionless
e. Application net
Answer: d, Moderate, p. 142

18. In connection-oriented routing, the _________ layer sets up a virtual circuit between the sender and the receiver.
a. transport
b. network
c. physical
d. data link
e. connection
Answer: a, Moderate, p. 142

19. ______________ routing is most commonly used when the application data or message can fit into one single packet.
a. Frame-oriented
b. Connection-oriented
c. Connectionless
d. Physical-oriented
e. Byte-oriented
Answer: c, Easy, p. 143

20. UDP is not commonly used for:
a. network management control messages
b. RIP messages
c. DHCP addressing messages
d. HTTP requests
e. routing control messages
Answer: d, Moderate, p. 143

21. With QoS routing different __________ are defined, each with different priorities.
a. classes of service
b. domain names
c. application layer addresses
d. data link layer addresses
e. classes of Internet addresses
Answer: a, Easy, p. 143

22. An application layer address using TCP/Ipv4 looks like:
a. 128.192.78.5
b. www.cba.uga.edu
c. user@cba.uga.edu
d. 00-0F-00-81-14-00
e. Building 4, Room 2, User 3
Answer: b, Moderate, p. 144

23. A client computer is assigned a data link layer address is by:
a. hardware manufacturers
b. software manufacturers
c. middleware manufacturers
d. network managers who configure a file in a computer’s network layer software package
e. ISO
Answer: a, Moderate, p. 145

24. ICANN:
a. developed the IPX/SPX network layer protocol
b. assigns data link layer addresses
c. approves which network layer addresses (usually, approved or assigned in groups or classes) can be used by an organization for its computers that will connect to the Internet
d. developed X.25 network layer protocol
e. refers to Interchange Computer Addressing Networks and Nodes
Answer: c, Moderate, p. 145

25. IPv6 will be based upon _________ -byte addresses.
a. 32
b. 24
c. 4
d. 16
e. 8
Answer: d, Easy, p. 146

26. IPv4 uses ________ bytes per Internet address.
a. 4
b. 32
c. 8
d. 24
e. 16
Answer: a, Moderate, p. 146

27. A(n) ________ refers to a group of computers that are logically grouped together by IP number.
a. IPv6 group
b. subnet
c. data link group
d. TCP group
e. application net
Answer: b, Easy, p. 146-147

28. A subnet mask of ___________ means that all computers with only the same first two bytes in their IPv4 addresses are on the same subnet.
a. 11111111.0.0.0
b. 255.255.255.0
c. 255.0.0.0
d. 255.255.0.0
e. 255.255.255.255
Answer: d, Moderate, p. 146

29. Dynamic addressing:
a. assigns a permanent network layer address to a client computer in a network
b. makes network management more complicated in dial-up networks
c. has only one standard, bootp
d. is always performed for servers only
e. can solve many updating headaches for network managers who have large, growing, changing networks
Answer: e, Moderate, p. 147-148

30. ___________ is the translation of application layer addresses into IP addresses.
a. Network interface card reversal
b. IPv6
c. Server name resolution
d. Subnet masking
e. Name service coding
Answer: c, Easy, p. 148

31. Server name resolution is done using the:
a. Address Resolution Protocol
b. Border Gateway Protocol
c. Internet Control Message Protocol
d. Routing Information Protocol
e. Domain Name Service
Answer: e, Moderate, p. 148

32. When TCP/IP translates an application layer address into an IP address, it sends a special __________ to the nearest DNS server.
a. broadcast message
b. DNS request packet
c. SNA packet
d. IPX message
e. X.25 packet
Answer: b, Easy, p. 149

33. Once your application layer software receives an IP address, it is stored in a:
a. hub table
b. server address table
c. hopping table
d. border gateway table
e. Internet Protocol control message table
Answer: b, Moderate, p. 149

34. When TCP/IP translates a network layer address into a data link layer address, it sends a special ____________ to all computers in the subnet.
a. physical layer packet
b. multicast message
c. X.25 message
d. broadcast message
e. application layer packet
Answer: d, Easy, p. 150

35. _________ is a specially formatted request used to perform IP address to data link address resolution.
a. Address Resolution Protocol
b. Domain Service Request
c. HTTP request
d. Link state request
e. Autonomous System Request
Answer: a, Moderate, p. 150

36. ___________ is the process of determining the path that a message will travel from sending computer to receiving computer.
a. Routing
b. Addressing
c. Interfacing
d. Broadcasting
e. Packetizing
Answer: a, Easy, p. 152

37. The _____________ is used by a computer to determine how messages will travel through the network.
a. routing table
b. configuration listing
c. linking loader
d. bus header assignment list
e. file allocation table
Answer: a, Moderate, p. 152

38. In its simplest form, the __________ has two columns: the first column lists every computer and device in the network, while the second column lists the computer or device to which that computer should send messages, if they are destined for the computer in the first column.
a. linking loader
b. routing table
c. configuration listing
d. bus header assignment list
e. file allocation table
Answer: b, Easy, p. 152

39. The three fundamental approaches to routing are:
a. circuitous, flat, and direct routing
b. connectionless, static, and connection-oriented
c. subordinate, master, and insubordinate routing
d. host, client, and client-server routing
e. centralized, static routing, and dynamic routing
Answer: e, Moderate, p. 154

40. An advantage of centralized routing is:
a. routing does reflect changing network conditions, such as computers that are overloaded by many messages
b. if anything happens to the computer developing the routing table, the routing tables cannot be changed until that computer is fixed, or until a new computer is selected to perform the function
c. routing decisions are simple
d. the routing tables are stored at all computers in the network
e. it requires more processing by each computer or router in the network than dynamic routing
Answer: c, Moderate, p. 154

41. With ________ routing, computers or routers count the number of hops along a route and periodically exchange information on the hop count with their neighbors.
a. circuitous
b. decentralized
c. distance vector
d. indirect
e. link state
Answer: c, Moderate, p. 154

42. ____________ refers to the type of routing in which the routing table is developed by the network manager and modifications are made only when computers are added to or removed from the network.
a. Adaptive routing
b. Dynamic routing
c. Static routing
d. Distance vector routing
e. Link state routing
Answer: c, Easy, p. 154

43. _______________ is a type of dynamic routing.
a. Static routing
b. Circuitous routing
c. Centralized routing
d. Link state
e. X.25 routing
Answer: d, Easy, p. 154-155

44. One drawback to dynamic routing is:
a. Routing usually does not reflect changing network conditions, such as computers that are overloaded by many messages
b. It cannot be used with non-government networks
c. The transmission of status information “wastes” network capacity that could be used to send user messages
d. It is the job of the network manager, not the computers or devices themselves, to maintain the routing table.
e. It requires less processing by each computer than static routing.
Answer: c, Moderate, p. 155

45. The ping command uses the most basic interior routing protocol on the Internet, which is the:
a. Border Gateway Protocol
b. Internet Control Message Protocol
c. Routing Information Protocol
d. Enhanced Interior Gateway Routing Protocol
e. Open Shortest Path First
Answer: b, Easy, p. 156-158

46. A type of message that is used when sending a message from one computer to another computer is called a:
a. unicast message
b. multicast message
c. broadcast message
d. guided message
e. radiated message
Answer: a, Easy, p. 158

47. A special type of message that is used when sending the same message to a specific group of computers is called a:
a. unicast message
b. multicast message
c. broadcast message
d. guided message
e. radiated message
Answer: b, Easy, p. 158

48. A special type of message that is used when sending the same message to all computers on a specific LAN or subnet is called a:
a. unicast message
b. multicast message
c. broadcast message
d. guided message
e. radiated message
Answer: c, Easy, p. 158

49. IGMP refers to:
a. Internet Giga Memory Parameters
b. Interchange Group Management Parameters
c. Internet Guided Meta Protocol
d. Internet Group Management Protocol
e. Interchange Guided Meta Protocol
Answer: d, Moderate, p. 159

50. Which of the following is not given to a client computer that is installed on a TCP/IP network so that it has the appropriate routing/addressing information?
a. application layer address
b. subnet mask
c. its own IP address
d. IP address of its DNS server
e. IP address of a gateway, router, or a switch outside of its subnet
Answer: a, Moderate, p. 159

Short Answer Questions

1. You have a new job. One of your co-workers is curious about the topic of finding unknown network layer addresses. She asks: “Can you tell me how my client computer can access a Web page on a Web server if it does not know the Web server’s address? Assume that my client computer knows all of the IP addresses and data link layer addresses in the network, except those for the web server itself.”
Answer: The network layer software of the client computer will realize it lacks the IP address for the Web server after searching its network layer address table and not finding a matching entry. In this case, it will issue a DNS request to its name server. Using its subnet mask, if it recognizes that the name server is outside of its subnet, it will create a TCP/IP DNS request packet and set the data link layer address to its gateway’s address.

The gateway would process the message and would transmit the packet using the name server’s Ethernet address. The name server would process the DNS request, and send the matching IP address back to the client. Once the client received the IP address for the Web server, it would store it in its network layer address table.
2. A client computer wants to access a web page on a Web server. Assume that it knows all of the IP addresses and data link layer addresses in the network, except those for the Web server itself. If the Web server were on the same subnet as the client, how would the client obtain the data link layer address for the Web server?
Answer: Once the client knows the IP address for the Web server that is stored it in its network layer address table, it would use its subnet mask to recognize that the Web server is on its subnet. However, it does not know the Web server’s Ethernet address. Therefore, TCP would broadcast an ARP request to all computers on its subnet, requesting that the computer, whose IP address matches the Web server’s IP address, respond with its Ethernet address.

This request would be processed by all computers on the subnet, but only the Web server would respond with an ARP packet giving its Ethernet address. The network layer software on the client would store this address in its data link layer address table and send the original Web request to the Web server using its Ethernet address.
3. Why does HTTP use TCP and DNS use UDP?
Answer: UDP is most commonly used for control messages such as addressing (DNS), routing control messages, and network management. TCP is used for connection-oriented application layer software such as a Web browser that would pass a HTTP packet. In these cases, before the first packet is sent, the transport layer sends an SYN packet to establish a connection. The data packets can flow once the connection is established, and the connection can be closed with a FIN packet once the data flow is finished.
4. What is the difference between unicast, broadcast, and multicast messages?
A broadcast message is sent to all computers in a particular subnet. This message will be received and processed by all computers in the same LAN, but not generally by computers outside the subnet. A unicast message is sent from one computer to one other computer. A multicast message is used to send the same message to a group of computers that may or may not be in the same subnet. Computers that wish to participate in a multicast send an Internet Group Management Protocol packet to the sending computer to make it part of a multicast group. Each multicast group is assigned a special IP address to identify the group. When the multicast session ends, the client computer sends another IGMP packet to the organizing computer to remove it from the multicast group.
5. What is a subnet and why do networks need them?
Answer: A subnet enables a sub-network to be logically grouped together by IP number. For example, it is customary to assign all the computers in the same LAN numbers that start with the same first three digits in an IP address, such as 128.192.56.x. Armed with a subnet mask and its own IP address, a computer in a TCP/IP network can determine which computers are on the same network and which computers are outside of its subnet. This is extremely important for message routing both inside and outside the subnet.
6. What is Quality of Service routing and why is it useful?
Quality of Service routing is a special type of connection-oriented routing in which different connections are assigned different priorities. For example, videoconferencing requires fast delivery of packets to ensure that the images and voices appear smooth and continuous; they are very time-dependent because delays in routing will seriously affect the quality of the service provided. E-mail packets, on the other hand, have no such requirements.
With QoS routing, different classes of service are defined, each with different priorities. It is common on certain types of networks, such as ATM. A packet of videoconferencing images would get higher priority than an SMTP packet with an e-mail message.
7. What are the key differences between distance vector dynamic routing and link state dynamic routing?
Answer: With distance vector dynamic routing, devices count the number of hops (one circuit) along a route. Computers periodically (every 1-2 minutes) exchange information on the hop count and sometimes the relative speed of the circuits in route with their neighbors only.
With link state dynamic routing, computers or routers track the number of hops in the route, the speed of the circuits in each route, and how busy each route is. Each computer periodically (every 15-30 minutes) exchanges this information with other computers in the network so that each computer has the most accurate information possible.
8. Under what conditions does decentralized dynamic routing provide better performance than decentralized static routing?
Answer: Dynamic routing provides better performance when there are multiple routes through a network and it is important to select the best route. Dynamic routing attempts to improve network performance by routing messages over the fastest possible route, away from busy circuits and busy computers.

9. What is DHCP and why would network managers want to use it?
Answer: Dynamic Host Control Protocol (DHCP) was developed in 1993 and is a standard commonly used with dynamic addressing in TCP/IP networks. Instead of providing a network layer address in a configuration file, a special software package is installed on the client that instructs it to contact a DHCP server using data link layer addresses. This message asks the server to assign the requesting computer a unique network layer address. The server runs a corresponding DHCP software package that responds to these requests and sends a message back to the client giving it its network layer address (and its subnet mask).
The DHCP server can be configured to assign the same network layer address to the computer each time it requests an address (based on its data link layer address), or it can lease the address to the computer by picking the “next available” network layer address from a list of authorized addresses. This greatly simplifies network management. With dynamic addressing, address changes need to be done only to the DHCP server, not to each individual computer. The next time each computer connects to the network or whenever the address lease expires, it automatically gets the new address.
10. Explain how multicasting works.
Answer: Computers wishing to participate in a multicast (e.g., for videoconferencing) send a message to the sending computer or some other computer performing routing along the way using a special type of TCP-level packet called Internet Group Management Protocol (IGMP). Each multicast group is assigned a special IP address to identify the group. Any computer performing routing knows to route all multicast messages with this IP address onto the subnet that contains the requesting computer. The routing computer sets the data link layer address on multicast messages to a matching multicast data link layer address. Each requesting computer must inform its data link layer software to process incoming messages with this multicast data link layer address. When the multicast session ends (e.g., the videoconference is over), the client computer sends another IGMP message to the organizing computer or the computer performing routing to remove it from the multicast group.
11. What four pieces of information does a computer using TCP/IP need in order to send messages using TCP/IP? Explain why each of these is required.
Answer: When a computer is installed on a TCP/IP network (or dials into a TCP/IP network), it must be given four pieces of network layer addressing and routing information before it can operate. This information can be provided by a configuration file, or via a bootp or DHCP server. The information is:

1. its IP address;
2. a subnet mask, so it can determine what addresses are part of its subnet;
3. the IP address of a DNS server, so it can translate application layer addresses into IP addresses; and
4. the IP address of a gateway computer leading outside of its subnet, so it can route messages addressed to computers outside of its subnet (this presumes the computer is using static routing and there is only one connection from it to the outside world through which all messages must flow; if it used dynamic routing, some routing software would be needed instead).

These four pieces of information are the minimum required. A server would also need to know its application layer address.

12. Suppose your manager asks which network protocol would be best for the company’s backbone network, TCP/IP or IPX/SPX. How would you answer the question? Discuss two major points. Your manager doesn't understand technical terms so be sure to explain any jargon you use.
Answer: Since TCP/IP will mostly likely become the dominant protocol within five years, I would suggest using it. Both TCP/IP and IPX/SPX are protocols that are compatible with a variety of different data link layer protocols (e.g., Ethernet, token ring) and can be used interchangeably in the same network. However, TCP/IP is the world’s most popular network layer protocol, used by almost 70 percent of all backbone, metropolitan, and wide area networks. In 1998, TCP/IP moved past IPX/SPX as the most common protocol used on LANs.
TCP/IP allows reasonably efficient and error-free transmission. Because it performs error checking, it can send large files across sometimes unreliable networks with great assurance that the data will arrive uncorrupted.
13. Suppose we add a new web server on the university campus. How many DNS servers need to be updated (at a minimum)? Suppose we start a new company and register a new Internet address for its web server. How many DNS servers need to be updated (at a minimum)? Explain.
Answer: If a new web server were added on the university campus, one DNS server would need to be updated at the minimum. Name servers can exchange information about new and changed addresses among themselves. This replication means that if only one DNS server knows the IP address, then other servers will eventually be replicated with this information. [Note: Assuming the university has its own DNS server, which is reasonable for most universities.]

Whenever you receive a set of Internet addresses (e.g., Classes A, B, or C), you must inform ICANN of the name and IP address of the name server that will provide DNS information for all addresses in that Class. Almost every organization with a Class B Internet address also has its own DNS server. Organizations with Class C addresses sometimes have their own DNS servers, but often rely on a DNS server provided by an Internet service provider. Two DNS servers at the minimum would have to be changed. [Note: A new Internet address is registered. You have to set up your own or change your ISPs DNS server, and have to change ICANN’s DNS server.]

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