Ryan's Midterm Study Guide (Chpt 1-7 + 10)

Question 1

What is a LAN?

Answer 1

A LAN is a Local Area Network. End devices connected to a single router that communicate with each other.

Question 2

What is a WAN?

Answer 2

A WAN is a Wide Area Network. Usually a series of LANS connected by something (the internet is the worlds largest WAN. Other examples include cloud services) WANs are normally run and owned by a company or ISP.

Question 3

What is the internet?

Answer 3

The internet is a massive WAN that connects thousands of LANs and WANs together.

Question 4

What is an Intranet?

Answer 4

An Intranet is a group of LANs and WANs run by a single organization, and only accessed by members of that organization (Example, the network that doctors and nurses connect to at a hospital)

Question 5

What is an Extranet?

Answer 5

An Extranet is an Intranet that members of the public have limited access to. (Example, Accessing your medical records through the My Health Portal login)

Question 6

How do LANS and WANs interconnect on the internet?

Answer 6

LANs connect to each other via WANs. They use routers to connect to other networks. WANs are connected via cabling, fiber or wireless transmissions. They talk to each other over the Internet through a cloud.

Question 7

What is a converged network?

Answer 7

A converged network is a network where multiple types of end devices all communicate. Converged networks share the same set of rules and standards to deliver voice, data and video over the same network infrastructure.

Question 8

Describe Fault Tolerance.

Answer 8

Fault tolerance pertains to limiting the amount of devices affected during a failure. (example. offering data multiple paths it can take. if one fails, it switches to the next until finding one that works)

Question 9

Describe QoS (Quality of Service)

Answer 9

QoS. Making sure a network can handle the stress that it is presented, and operate at an acceptable speed. The main focus of QoS is prioritizing time sensitive traffic.

Question 10

Describe Scalability.

Answer 10

Scalability is the ability for a network to grow along with its user base. It must be able to take on new users and applications without disrupting current service.

Question 11

What are the two main components of network security?

Answer 11

Network Infrastructure Security Hardware that prevents security breaches from occurring.

Network Information Security. Software that prevents security breaches from occurring.

Question 12

Describe Basic network infrastructure and core security (confidentiality, integrity, availability)

Answer 12

Confidentiality: Information must only be shared with people who are meant to see it.

Integrity: Data must not be altered on its way to its destination, and has to be in its original state on arrival

Availability: Timely access to a network.

Question 13

Name some basic threats to a network.

Answer 13

Viruses
 Worms,
Trojan Horses
 Spyware
 Day Zero attacks ( attacks on the first few hours after a network goes live) 
DoS attacks (Denial of Service)
Identity theft

Question 14

Name some basic security threat solutions.

Answer 14

Antivirus, antispyware, firewall filtering, access control lists, intrusion prevention systems, VPNS.

Question 15

What is the difference between a Physical topology and a Logical topology?

Answer 15

Physical Topology: Illustrates the Physical locations of devices and physical connections between them (cabling diagrams)

Logical Topology: Shows the Logical connections between devices (IP addressing, ports, gateways)

Question 16

What is the main purpose of the Cisco IOS?

Answer 16

Allows you to configure routers and switches directly

Allows you to set up a network that isn’t currently connected via directly plugging into devices with a console cable.

Allows you to directly communicate with devices using keyboard commands.

Question 17

What are the features and functions of the Cisco IOS?

Answer 17

The Cisco IOS allows users to use keyboard commands to run CLI based networking programs and view outputs on a monitor.

Question 18

From User exec mode, what commands would you have to enter to assign a hostname and MOTD to a switch?

Answer 18

enable
config t
hostname name
banner motd #motd#

Question 19

What command has to be punched in after assigning a password to the console?

Answer 19

login

Question 20

What does the command copy run start do in the CLI?

Answer 20

Copy’s the running configuration to the startup configuration. In the case of a power cycle, the device will start from this config.

Question 21

What command encrypts all plain text passwords in the CLI?

Answer 21

service password-encryption

Question 22

What ways can you access the Cisco IOS for configuration purposes?

Answer 22

Via console connection physically to a device via a console cable.

Secure Shell (SSH) In band method for remotely creating a secure CLI connection and virtual interface over a network.

Telnet. Unsecure In band connection to a virtual interface. Like SSH but does not provide a secure encrypted connection.

Question 23

How do you access privileged exec mode in the CLI?

Answer 23

From User exec mode, type the “enable” command

Question 24

Which mode in the CLI is known as the “view only” mode?

Answer 24

User Exec. Enabled by pressing enter on connection to the CLI.

Question 25

What do devices need to communicate to each other across network media?

Answer 25

Devices need a unique IP address to distinguish between each other over a network.

Question 26

What are the basic rules of communication? How do they apply to a network?

Answer 26

The message must have an identified sender and receiver

The message must be written in common language and grammar.

The message must be sent in a timely manner.

The message must be confirmed or received at the destination.

Question 27

What is the role of Ethernet and wireless protocols?

Answer 27

Ethernet and wireless protocols govern the physical connections between the media and the network.

Question 28

What is the role of DHCP and IPV6 protocols?

Answer 28

IPv6 protocols provide IP addressing information, tells the device where to send packets over the network (basically the same as IPv4).

DHCP gives information when a device doesn’t know the name of the end device, but knows the IP address.

Question 29

What is the role of the TCP protocol?

Answer 29

TCP is a protocol used to ensure reliability, and to make sure packets arrive at their destination. If a packet fails to reach its destination, TCP will resend it.

Question 30

Define message encoding and decoding.

Answer 30

Encoding is when a message is converted into another acceptable form of transmission.

When the message reaches its destination, it is decoded back into its original format.

Question 31

Define message formatting

Answer 31

Specific message types have to stick to formatting rules depending on the type of message. Compare it to sending a letter. If the formatting of the address on the front of the envelope is incorrect, the letter will never arrive.

Question 32

Define Message Size in networking.

Answer 32

When a message is large, it has to be broken into smaller pieces to be sent over the network. These pieces need to be numbered and sent in a sequence to make sure they are put back together correctly at the destination.

Question 33

What are the main components of message timing?

Answer 33

Flow control. Controls the speed messages are sent over the network. If messages are sent too fast, they can not be read by the destination device.

Response timeout, When a message is sent, if there is no response in a certain period of time, the message will time out. The acceptable amount of time before the message is terminated is defined by network protocols.

Access method. Controls when messages can be sent to avoid collisions.

Question 34

What is the difference between broadcast, unicast and multicast?

Answer 34

Broadcast, a message is sent to all end devices on a network.

Multicast, a message is sent to specific end devices on a network.

Unicast, a message is sent from one end device to only one other end device.

Question 35

Define data encapsulation and decapsulation.

Answer 35

Data encapsulation is the process of breaking down larger files into smaller pieces and adding protocol information as it traverses over the network.

Decapsulation is putting the pieces back together once it reaches its destination.

Question 36

Name the layers of the OSI model and the term associated with the data at each layer.

Answer 36

Physical Layer - Bits.
Data Link Layer - Frames
Network Layer - Packets
Transport Layer - Segments
Session Layer - Data 
Presentation Layer - Data 
Application layer - Data

Question 37

Name the layers of the TCP/IP model.

Answer 37

Application Layer
Transport Layer
Network Layer
Network Interface Layer.

Question 38

What differentiates the TCP/IP and OSI model?

Answer 38

The OSI model is outdated and wasn’t created with the internet in mind. It is not practically used anymore and instead is used more as an outline.

Question 39

Which organization created the OSI model?

Answer 39

The International Organization for Standardization (IISO)

Question 40

What is sequencing and how is it used during the encapsulation process?

Answer 40

Sequencing is the process of numbering each packet after it has been broken down during the encapsulation process. This occurs during the data link layer.

It is used to make sure that when packets arrive at their destination, they are decapsulated back into the correct spots.

Question 41

What is the difference between a logical and physical addresses?`

Answer 41

Logical Addresses are dynamic IP addresses. They are responsible for delivering the IP packet from source to destination

Physical addresses or MAC addresses are burnt into devices and each one is unique to the media. Responsible for delivering the data link frame from one NIC to another NIC on the same network.

Question 42

What does NIC stand for?

Answer 42

Network Interface Card

Question 43

Name some of the general characteristics of Physical Layer Protocols.

Answer 43

The physical layer is responsible for PHYSICALLY connecting devices together.
The 3 main characteristics are:
Physical Components
Encoding
Signaling
The main physical layer device is the router.

Question 44

Name some of the organizations that govern the Physical layer.

Answer 44

ISO, TIA/EIA, ITU, ANSI, IEEE, regional organizations like the FCC in the US and the CSA in Canada.

Question 45

Describe Encoding.

Answer 45

Encoding is the method of turning streamed data bits into a predefined code. Codes are groupings of bits that can be understood by both the sender and the receiver.

Question 46

Describe Signaling

Answer 46

Signaling is when the physical layer generates signals that are converted into an understandable code.

The main methods of signaling are electronic, optical and wireless.

Physical layer standards define what signals stand for 1s and 0s.

Ex. The length of an electronic pulse is what defines it as 1 or 0. A longer pulse could mean a 1 and a short pulse could mean a 0.

Question 47

Define bandwidth, goodput, throughput and latency.

Answer 47

Bandwidth is the capacity that media can carry across a network. Better bandwidth = higher speeds.

Latency, the amount of time including delay that data takes to travel

Throughput. Measure of the transfer of bits over a period of time.

Goodput. Measure of usable data transferred over a given period of time.

Question 48

What are the main functions of the LLC and MAC sublayers?

Answer 48

LLC sublayer. Operates on IEEE 802.2. Communicates between the networking software at the upper layers and the device hardware at the lower layers.

MAC sublayer. Operates on IEEE 802.11. Responsible for data encapsulation and media access control.

Question 49

What does the MAC sublayer control?

Answer 49

Frame Delimiting. Provides identifying delimiters for fields within a frame.

Addressing. Provides source and destination addressing to the frame.

Error detection. Detects transmission errors in a frame.

Question 50

Describe the header of the Data Link Frame.

Answer 50

The header identifies the Frame start (beginning limit of the frame) the addressing (source and destination information) the type of frame (Identifies the layer 3 protocol) and the control (identifies special flow control services)

Question 51

Describe the data portion of the Data Link Frame

Answer 51

The data contains the payload of information the frame is attempting to transfer.

Question 52

Describe the trailer of the Data Link Frame.

Answer 52

The main function of the trailer is error detection. It also includes the frame stop which identifies the end limit of the frame.

Question 53

Describe the process of Ethernet (data) encapsulation.

Answer 53

Ethernet is a combination of both the Data Link and the Physical layers of the OSI model.
Ethernet frames contain both the source and destination MAC addresses, which is the burned in physical address of a media. The ethernet layer also consists of a Frame Check Sequence (FCS) which is used for error detection.

Question 54

Describe a MAC address.

Answer 54

A MAC address is a 48-bit binary string condensed into a 12 bit hex code.

MAC addressing provides device specific addressing in the data link layer. All MAC addresses must be unique to the Ethernet device.

Question 55

What is the purpose of an OUI?

Answer 55

When an ethernet device is created, it has to register to the IEEE and obtain a 6 digit hex code. This unique code is known as the Organizationally Unique Identifier (OUI)

Question 56

What is the format for Unicast, Broadcast and Multicast MAC addresses?

Answer 56

Broadcast: FF.FF.FF.FF.FF.FF Floods out all ports and is sent to all devices on a network.

Unicast. The source MAC address of a device.

Multicast. If the destination is an IPv4 Address, the reserved destination MAC is 01-00-5E. When it is IPv6 the destination MAC is 33-33. It is flooded out all ports except for the incoming port. Can only be used as a destination address, the source address still has to be unicast.

Question 57

Describe the store-and-forward switching method.

Answer 57

Store and forward receives the entire frame and computes the CRC. This performs error detection on the frame, and drops it if transmission errors are detected.

Question 58

Describe the fast-forward switching method.

Answer 58

Fast-Forward switching has the lowest latency of all forwarding methods. The packet is immediately forwarded after reading the addressing information.

Because fast-forward switching uses no error detection, if a frame contains an error the NIC has to discard the faulty packet on arrival.

Question 59

Describe the fragment-free switching method.

Answer 59

Fragment-Free Switching is the middle ground between Fast-Forward and Store-and-Forward. An error check is performed on the first 64 bytes of a frame before forwarding. Most collisions occur in these first bytes of a frame.

Question 60

What is the purpose of a CAM table?

Answer 60

A CAM table stores MAC addressing information on a switch. It uses this table to make forwarding decisions. When it hasn’t seen a MAC address before, it stores the address in the CAM table.