Question 1

Which of the following IEEE standards is associated with VLAN trunking?

Accepted Answer

802.1Q is the IEEE standard for VLAN trunking. Newer Cisco and Juniper switches use 802.1Q as the tagging method.
Key Takeaway: VLAN Trunking Protocol, or VTP proprietary messaging protocol, operates on OSI layer 2. VTP is used to manage the Virtual Local Area Networks, or VLANs, for the entire network. VTP supports addition, deletion, and renaming of VLANs. IEEE 802.1Q, or VLAN Tagging, is networking that allows multiple bridged networks to transparently share the same physical network link without leakage of information between networks.

Question 2

You observe that CAT5e cables are lying around on the floor at various divisions of the APR.com office. What should you do about these cables?

Accepted Answer

All the CAT5e cables lying on the ground should be re-routed using a protective sheath.
Key Takeaway: Network cables should never be allowed to be on the floor. This may damage the cable and in turn slow down or bring down the network. All cables should be rerouted using a protective sheath.

Question 3

Jack is having a tough time monitoring the users who want to access illegitimate web sites through the corporate Internet connection. At this point in time, the corporate network is not secure and protected. Jack wants to block unauthorized traffic from entering or leaving his corporate network. Which network device should he use?

Accepted Answer

To prevent a network from requesting or receiving unauthorized traffic, Jack should use a firewall.
Key Takeaway: A firewall is a part of a computer system or network that is designed to block unauthorized access while permitting authorized communications. Firewalls are configured to permit, deny, encrypt, and decrypt computer traffic between different security domains based upon a set of rules and other criteria. They can be implemented in either hardware or software, or a combination of both. Firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets. All messages entering or leaving the intranet pass through the firewall. The firewall examines each message and blocks those that do not meet the specified security criteria.

Question 4

You are trying to get on a secured wireless network. You can browse to the network, but cannot connect. Your client is set to use Wired Equivalent Privacy, and you know you have the passphrase right. What is the most likely problem?

Accepted Answer

It is most likely in this case that the security is being provided by Wi-Fi protected access, or WPA.
Key Takeaway: WEP should never be used when securing a wireless implementation. It has been shown to be easily hackable. WPA2 is the best encryption standard to use when securing a wireless network.

Question 5

Which of the following TCP/IP ports does the LDAP protocol use?

Accepted Answer

LDAP uses TCP port 389 for its operation.
Key Takeaway: LDAP (Lightweight Directory Access Protocol) is an application protocol for querying and modifying directory services running over TCP/IP. A client starts an LDAP session by connecting to an LDAP server known as the Directory System Agent (DSA) using the default TCP port 389. The client then sends an operation request to the server and the server sends responses in return.

Question 6

Jack has installed a basic router for a SOHO network. After the installation, the PCs connected to the router are not able to acquire an IP address. Which of the following did he fail to configure correctly?

Accepted Answer

DHCP provides IP addresses to client computers on a network. If the computers are not able to acquire an IP address, the DHCP service may not have been properly configured.
Key Takeaway: Dynamic Host Configuration Protocol (DHCP) is a network application protocol used by DHCP clients to obtain configuration information for operation in an Internet Protocol network. This protocol reduces system administration workload, allowing networks to add devices with little or no manual intervention. When a DHCP-configured client connects to a network, the DHCP client sends a broadcast query requesting necessary information from a DHCP server. The DHCP server manages a pool of IP addresses and information about client configuration parameters such as default gateway, domain name, the DNS servers, and other servers, such as timeservers.

Question 7

What are the default ports for HTTP and HTTPS?

Accepted Answer

80 and 443 are the default ports for HTTP and HTTPS respectively.
Key Takeaway: Since 80 and 443 are the default ports for HTTP and HTTPS, an administrator needs to make sure these ports are open on the firewall, and that the server is listening on them.

Question 8

You have added a new department in your building with 100 new employees. You already have a wireless network setup with optimal coverage. What should you do to increase the range of the wireless network?

Accepted Answer

The best option is to place more access points without disturbing the existing setup.
Key Takeaway: You should not change a well-placed access point setup, since it may hinder the current coverage aspects. Aligning the antennas may also hinder the coverage. Instead of creating a new wireless network, place more access points in the new department.

Question 9

Jack reports that when the phone rings in his house, the wireless on his laptop becomes disconnected. Which of the following is a likely cause of this problem?

Accepted Answer

Wireless networks may function intermittently when a cordless phone is operating at 2.4 GHz in the proximity of the network.
Key Takeaway: To avoid wireless network interference from a cordless phone:
• Move the phone at least 50 feet away from the wireless network.
• Switch to a 5.8 GHz phone.
• Use a different channel on the 2.4 GHz phone that does not overlap with the Wi-Fi network.

Question 10

Which of the following statements about network protocols are true? Choose two.

Accepted Answer

TCP/IP (Transmission Control Protocol/Internet Protocol) is the main communications protocol for the Internet, Intranets, and Extranets. NetBIOS (Network Basic Input/Output System) is a program for local area networks.
Key Takeaway: TCP/IP allows net communications across all networks. NetBIOS only supports LAN communications and not WAN traffic (Internet).

Question 11

Jack is a network technician troubleshooting a network issue. Which of the following troubleshooting steps should he take first to resolve this issue?

Accepted Answer

Jack needs to ask the user who reported the issue to explain the symptoms in detail. This could help him to isolate the issue and find a suitable solution.
Key Takeaway: The first step in troubleshooting an issue is to get more information, such as symptoms, any changes made, or any components/software removed or installed. This heads the troubleshooting process in the right direction.

Question 12

Dave is a new network consultant and is designing a new network for a small business. Dave discovers that the entire LAN, whose addresses are all 192.168.1.x/24, will need Internet access. What device must Dave install between the LAN and the Internet?

Accepted Answer

Dave would need a router between the LAN and the Internet.
Key Takeaway: Routers are necessary to route network traffic between networks. Since, by definition, Johnny's network is on a different network than the Internet, he would need a router. A firewall is recommended, of course, but not necessary.

Question 13

A number of employees are complaining about slow Internet connection to John, the IT supervisor. John suspects crosstalk and wants to use the cabling standard that is least susceptible to crosstalk. Which type of cabling should he use?

Accepted Answer

Fiber optic cabling is least susceptible to cross talk, even though the cables run beside each other.
Key Takeaway: Crosstalk (XT) refers to any phenomenon by which a signal transmitted on one circuit or channel of a transmission system creates an undesired effect on another circuit or channel. Crosstalk is usually caused by undesired capacitive, inductive, or conductive coupling from one circuit. Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of light through an optical fiber. An optical fiber consists of a core, cladding, and a buffer (protective outer coating), in which the cladding guides the light along the core by using total internal reflection. Proper thickness of the cladding ensures elimination of crosstalk.

Question 14

How does a router handle broadcasts?

Accepted Answer

Routers initiate broadcasts, but do not forward them.
Key Takeaway: A router is a device used to break up broadcast domains. A broadcast domain is a logical part of a network where any network device can transmit data directly to another device without going through a routing device. A router blocks a layer-2 broadcast, like an ARP request, which is sent by a machine on the network to all devices on the network. The only time when a router will originate a broadcast is when a router is sending update information using routing protocols like RIP.

Question 15

Which of the following devices is used to break up a broadcast domain?

Accepted Answer

A router is used to break up broadcast domains.
Key Takeaway: A broadcast domain is a logical division of a computer network in which all nodes can reach each other by broadcast at the data link layer. It represents where a layer-2 broadcast will propagate. Switches forward a broadcast out all of the ports in the same VLAN as the receiving interface. The router breaks up a broadcast domain and drops these broadcast packets. This is vital to avoid broadcasts from every computer being sent across the entire network.

Question 16

Which of the following TCP features allows a receiving computer to inform the sending computer that the transmission rate needs to be slower?

Accepted Answer

The Flow Control TCP feature allows a receiving computer to inform the sending computer that the transmission rate needs to be slower.
Key Takeaway: Flow Control plays a vital role in controlling the speed at which the data is transmitted from a sending computer to a receiving computer. Many times, the receiving computer cannot match the bandwidth of the sending computer. Flow control modulates the data transfer at a speed that is acceptable to both computers.

Question 17

What does the jam signal on an Ethernet segment signify?

Accepted Answer

A jam signal indicates a collision on the wire.
Key Takeaway: A jam signal usually occurs on an Ethernet segment, typically on a CSMA/CD network. A jam signal carries a 32-bit binary pattern sent by a computer to inform the other computers that they must not transmit. After sending the jam signal, each of the senders will wait a random amount of time before beginning the entire process over. The random time helps to ensure that the two devices don't transmit simultaneously again.

Question 18

Which of the following fields make up a switch's bridge ID (BID)?

Accepted Answer

The bridge ID is made up of a MAC address and Bridge priority.
Key Takeaway: Bridge ID is used to select the root bridge of a spanning tree. It is made up of the MAC address and the bridge's priority value. Active bridges use this bridge ID to determine the cheapest transmission path to the root bridge.

Question 19

4 VLANs (A, B, C, and D) are connected to a switch. A host on VLAN A sends a broadcast. What will the switch do now?

Accepted Answer

The switch forwards the broadcast to all hosts on VLAN A, except the port it received the broadcast on.
Key Takeaway: VLAN is a group of hosts that communicate as if they were attached to the Broadcast domain, regardless of their physical location. It has the same attributes as a physical LAN and allows for hosts to be grouped together, even if they are not located on the same network switch. Whenever a broadcast is sent on a switch that has multiple VLANs connected, the switch forwards the broadcast to all hosts on the VLAN from where the broadcast originated. However, it will not forward it to the port that it received the broadcast on.

Question 20

David is running Frame Relay LMI Autosense on a Cisco router. The router sends out three LMI messages. How many should it get back from the DCE?

Accepted Answer

The router should get only one LMI message from the DCE.
Key Takeaway: The Local Management Interface, or LMI, messages are sent between the DCE (typically the service provider) and the DTE (the Cisco router). LMI Status messages serve as keep-alives for a frame connection. If these keep-alives are not continually received by both the DCE and the DTE, the frame connection will drop. The LMI also indicates the PVC status to the router, reflected as either active or inactive. In an LMI Autosense, the DTE or the Cisco router will send out three LMI messages, one of each type (Cisco, ansi, and q933a). The DCE will return only one and the DTE will only send that type from then on.

Quiz 3: Networking