Home > Articles

Networking Devices

This chapter is from the book

Review and test yourself

The following sections provide you with the opportunity to review what you learned in this chapter and to test yourself.

The facts

  • Both hubs and switches are used in Ethernet networks. Token Ring networks, which are few and far between, use special devices called multistation access units (MSAUs) to create the network.

  • The function of a hub is to take data from one of the connected devices and forward it to all the other ports on the hub.

  • Most hubs are considered active because they regenerate a signal before forwarding it to all the ports on the device. In order to do this, the hub needs a power supply.

  • Rather than forwarding data to all the connected ports, a switch forwards data only to the port on which the destination system is connected.

  • Switches make forwarding decisions based on the Media Access Control (MAC) addresses of the devices connected to them to determine the correct port.

  • In cut-through switching, the switch begins to forward the packet as soon as it is received.

  • In a store-and-forward configuration, the switch waits to receive the entire packet before beginning to forward it.

  • FragmentFree switching works by reading only the part of the packet that enables it to identify fragments of a transmission.

  • Hubs and switches have two types of ports: Medium Dependent Interface (MDI) and Medium Dependent Interface-Crossed (MDI-X).

  • A straight-through cable is used to connect systems to the switch or hub using the MDI-X ports.

  • In a crossover cable, wires 1 and 3 and wires 2 and 6 are crossed.

  • Both hubs and switches come in managed and unmanaged versions. A managed device has an interface through which it can be configured to perform certain special functions.

  • Bridges are used to divide up networks and thus reduce the amount of traffic on each network.

  • Unlike bridges and switches, which use the hardware-configured MAC address to determine the destination of the data, routers use the software-configured network address to make decisions.

  • With distance-vector routing protocols, each router communicates all the routes it knows about to all other routers to which it is directly attached.

  • RIP is a distance routing protocol for both TCP and IPX.

  • Link state protocols communicate with all other devices on the network to build complete maps of the network. They generate less network traffic than distance vector routing protocols but require more powerful network hardware.

  • Open Shortest Path First (OSPF) and NetWare Link State Protocol (NLSP) are the most commonly used link state routing protocols used on IP and IPX networks respectively.

  • The term gateway is applied to any device, system, or software application that can perform the function of translating data from one format to another.

  • A CSU/DSU acts as a translator between the LAN data format and the WAN data format.

  • Wireless network devices gain access to the network via Wireless Access Points.

  • Modems translate digital signals from a computer into analog signals that can travel across conventional phone lines.

Key terms

  • Hub

  • Bridge

  • Gateway

  • Network Interface Cards

  • ISDN adapters

  • Switch

  • Router

  • CSU/DSU

  • System area network cards

  • Wireless Access Points (WAPs)

  • Modems

  • MAC addresses

  • Distance vector

  • Link state

  • Dynamic routing

  • Static routing

  • NLSP

  • OSPF

  • RIP

  • Convergence

  • Bridging loops

Practice exam

Question 1

Users are complaining that the performance of the network is not satisfactory. It takes a long time to pull files from the server and, under heavy loads, workstations can become disconnected from the server. The network is heavily used and a new video conferencing application is about to be installed. The network is a 100BaseT system created with Ethernet hubs. Which of the following devices are you most likely to install to alleviate the performance problems?

  1. Switch

  2. Router

  3. Bridge

  4. Gateway

The correct answer is A. Replacing Ethernet hubs with switches can yield significant performance improvements. Of the devices listed, they are also the only one that can be substituted for hubs. Answer B, router, is incorrect as a router is used to separate networks, not as a connectivity point for workstations. A bridge could be used to segregate the network and so improve performance, but a switch is a more obvious choice in this example. Therefore, answer C is incorrect. Answer D, gateway, is incorrect. A gateway is a device, system, or application that translates data from one format to another.

Question 2

Which of the following devices forwards data packets to all connected ports?

  1. Router

  2. Switch

  3. Bridge

  4. Hub

The correct answer is D. Hubs are inefficient devices that send data packets to all connected devices. Many of today's networks are upgrading to switches that pass data packets to the specific destination device. This method significantly increases network performance.

Question 3

Of the following routing methods, which is likely to take the most amount of administration time in the long term?

  1. Static

  2. Link state

  3. Distance vector

  4. Dynamic

The correct answer is A. Static routing will take more time to administer in the long term, as any changes to the network routing table must be entered manually. Answers B and C are incorrect. Distance vector and link state are both dynamic routing methods. Answer D is also incorrect. Dynamic routing might take more time to configure initially, but in the long term it will require less administration time. It can adapt to changes in the network layout automatically.

Question 4

Your manager asks you to look into some upgrades for your network. The current network is a 10Base2 system and you have been experiencing numerous hard-to-track-down cable problems. As a result, you have decided to upgrade to a 10BaseT system. On the networking vendor's price list are both active and passive hubs. The passive hubs are considerably cheaper than the active ones and you are tempted to opt for them so that you come in under budget. A colleague advises you against the purchase of passive hubs. What is the primary difference between an active and a passive hub?

  1. Passive hubs do not offer any management capabilities.

  2. Passive hubs cannot be used in full-duplex mode.

  3. Passive hubs do not regenerate the data signal.

  4. Passive hubs forward data to all ports on the hub, not just the one for which they are intended.

The correct answer is C. An active hub regenerates the data signal before forwarding it. Answer A is incorrect. The management capabilities of a hub have nothing to do with the active/passive aspect of the device. Answer B is incorrect. Hubs are not able to operate in full-duplex mode. Only network switches are able to perform this function in this context. Answer D describes the function of a switch, not a hub.

Question 5

Which of the following statements best describes a gateway?

  1. It is a device that allows data to be routed from one network to another.

  2. It is a term used to refer to any device that resides at the entrance of a network.

  3. It is a device, system, or application that translates data from one format to another.

  4. It is a network device that can forward or block data based on the MAC address embedded within the packet.

The correct answer is C. A gateway can be a device, system, or application that translates data from one format to another. Answers B and D are more likely to describe a router than a gateway. Answer D describes a bridge. A bridge is a device that is used to segregate a network. It makes forwarding or blocking decisions based on the MAC address embedded within the packet.

Question 6

You have a thin coaxial-based Ethernet network and are experiencing performance problems on the network. By using a network performance-monitoring tool, you determine that there are a large number of collisions on the network. In an effort to reduce the collisions you decide to install a network bridge. What kind of bridge are you most likely to implement?

  1. Collision bridge

  2. Transparent bridge

  3. Visible bridge

  4. Translational bridge

The correct answer is B. A transparent bridge can be used to segment a network, which reduces the amount of collisions and the overall network traffic. It is called transparent because the other devices on the network do not need to be aware of the device and will in fact operate as if it wasn't there. Answer D is incorrect as a translational bridge is used in environments where it is necessary to translate from one data format to another. Such a conversion is not necessary in this scenario. Answers A and C are invalid. There is no such thing as a collision bridge or a visible bridge.

Question 7

Which of the following represents a valid MAC address?

  1. 00-D0-56-F2-B5-12

  2. 00-63-T6-4H-7U-78

  3. 00-62-DE-6F-D2

  4. 000-622-DE5-75E-EA6

The correct answer is A. A MAC address is a 6-byte address which is expressed in hexadecimal format. Answer B contains the letters T and U, which are not valid. Hexadecimal format uses only numbers and the letters A through F. For this reason, answer B is incorrect. Answer C is only five bytes and so is incorrect. Answer D is incorrect because a byte in hexadecimal is expressed in two characters and the answer uses three.

Question 8

Which of the following devices passes data based on the MAC address?

  1. Hub

  2. Switch

  3. MSAU

  4. Router

The correct answer is B. When determining the destination for a data packet, the switch learns the MAC address of all devices attached to it and then matches the destination MAC address in the data it receives. None of the other devices pass data based solely on the MAC address.

Question 9

What is the speed of the 16550 UART chip?

  1. 921,600

  2. 430,800

  3. 115,200

  4. 9600

The correct answer is C. 115,200 is the speed of the 16550 UART chip. Answer A is incorrect as 921,600 is the speed of the 16750 and 16950 UART chips. Answer B is incorrect as 430,800 is the speed of the 16650 UART chip and 9600 is the speed of the 8250 UART chip.

Question 10

Which of the following devices would you find only on a Token Ring network?

  1. Hub

  2. Switch

  3. MSAU

  4. Router

The correct answer is C. A Multistation Access Unit (MSAU) is used as the connectivity point on a Token Ring network. Answers A and B are incorrect. Switches and hubs are associated with Ethernet networks. Answer D is incorrect. Routers can be found on both Token Ring and Ethernet networks.

 

Want to know more?

Sheldon, Thomas. McGraw-Hill's Encyclopedia of Networking and Telecommunications. McGraw-Hill Professional Publishing, 2001.

Tulloch, Mitch. Microsoft Encyclopedia of Networking (with CD-ROM). Microsoft Press, 2000.

Pearson IT Certification Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from Pearson IT Certification and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about Pearson IT Certification products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites; develop new products and services; conduct educational research; and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by Adobe Press. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.pearsonitcertification.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020