Ccna Exploration Chapter 2

Front 1

What are the three common elements of network communication methods?

Back 1

Message, Destination, and Channel

Front 2

Define: Channel?

Back 2

A channel consists of the media that carries a signal over a network.

Front 3

Currently, how are messages efficiently communicated over a network?

Back 3

By process of segmentation

Front 4

Define: Segmentation

Back 4

The process in which messages are broken into smaller pieces (segments) that can be transported across a medium.

Front 5

What are the two primary benefits of segmentation?

Back 5

Multiplexing and decreased network congestion.

Front 6

Define: Multiplexing

Back 6

Multiplexing allows interleaving of segments so users can share the bandwidth.

Front 7

What is the downside of using segmentation and multiplexing?

Back 7

Time consuming

Front 8

What are the components of a Network?

Back 8

Devices, Media, Services, and Processes.

Front 9

Define: End Device

Back 9

Equipment that is either the source or the destination of a message on a network.

Front 10

Define: Host

Back 10

An end device that can both send and receive messages.

Front 11

Define: Client

Back 11

An end device that requests information and services

Front 12

What is the role of an end device?

Back 12

To be the source, or the destination of a message on a network.

Front 13

Define: Host Address

Back 13

A unique identifier used by hosts to deliver messages to other hosts on a network.

Front 14

Define: Physical Address

Back 14

A Data Link Layer address. For example, a MAC address.

Front 15

Define: Intermediary Device

Back 15

A device which connects individual hosts to a network and can connect multiple individual networks to form an internetwork. Also manages network data flow.

Front 16

Define: Network Access Devices

Back 16

Connects end users to their network. Examples are hubs and switches. Intermediary.

Front 17

Define: Internetwork Devices

Back 17

Conencts one network to one or more other networks. A router is a main example. Intermediary.

Front 18

Define: Communication Servers

Back 18

Routes services such as IPTV and wireless broadband. Intermediary.

Front 19

Define: Modems

Back 19

Connects users to servers and networks through telephone or cable. Intermediary.

Front 20

Define: Security Devices

Back 20

Secures the network with devices such as firewalls. Intermediary.

Front 21

What six functions to the processes running on intermediary devices perform?

Hint: R.M.N.D.C.P.

Back 21

1. Regenerate and retransmit data signals.

2. Maintain information about what pathways exist through the network and internetwork.

3. Notify other devices of error and communication failures.

4. Direct data along alternate pathways when there is a link failure.

5. Classify and direct messages according to QoS priorities.

6. Permit or deny the flow of data, based on security settings.

Front 22

What are the three main types of media used in a network today?

Back 22

Copper, Fiber-Optic, Wireless

Front 23

Define: Encoding

Back 23

Refers to the way data is converted into patters of electrical, light, or electromagnetic energy, dependent of which type of media is being used.

Front 24

What type of encoding does Copper use?

Back 24

Electrical pulses

Front 25

What type of encoding does Fiber-Optic use?

Back 25

Light pulses

Front 26

What type of encoding does Wireless use?

Back 26

Electromagnetic waves

Front 27

When choosing network media, what four factors must administrators consider?

Hint: D.E.B.C.

Back 27

1. The distance the media can carry the signal

2. The environment in which the media will operate

3. The bandwidth requirements for users

4. The cost of installation, and compatible devices

Front 28

What are the three basic differences between different networks types?

Back 28

1. The size of the area covered

2. The number of users connected

3. The number and types of services available.

Front 29

Define : Local-Area Network (LAN)

Back 29

A network under the control of a common administration.

Front 30

Define : Wide-Area Network

Back 30

A network of geographically separated LANs. There are usually no end users on WANs.

Front 31

Define: Telecommunications Service Provider (TSP)

Back 31

Provides WAN services for companies.

Front 32

Define: Internetwork

Back 32

A collection of two or more LANs connected by WANs. The most popular Internetwork is the Internet. Also known as a "data network" or simply "network."

Front 33

Define: Intranet

Back 33

A private network, closed to public access.

Front 34

Define: Internet Service Providers (ISP)

Back 34

Provide end users with internet access. May also provide TSP services.

Front 35

Define: Protocol

Back 35

A rule that defines what tasks a service or device will perform.

Front 36

Define: Protocol Suite

Back 36

A group of protocols that work together to ensure successful host-to-host communication.

Front 37

What processes do Network Protocols describe?

Back 37

1. The format or structure of the message

2. The method by which networking devices share information about pathways with other networks

3. How and when error and system messages are passed between devices

4. The setup and termination of data transfer sessions

Front 38

Individual protocols in a protocol suite may be vendor-specific and proprietary.

In this context, define "Proprietary"

Back 38

One company or vendor controls the definition of the protocol and how it functions.

Front 39

Define : Hypertext Transfer Protocol (HTTP)

Back 39

An Application Protocol which defines the content and formatting of the requests and responses exchanged between the web client and web server.

Front 40

Define: Transmission Control Protocol (TCP)

Back 40

A Transport Protocol which manages the individual conversations between web servers and their clients. TCP segments messages and controls segment size and data flow between web servers and their clients.

Front 41

Define: Internet Protocol (IP)

Back 41

A Network Layer protocol which is responsible for taking the formatted segments from TCP, encapsulating them into packets, assigning the appropriate addresses, and selecting the best path to the destination host.

Front 42

Define: Network Access Protocols:

Back 42

Network access protocols describe two primary functions, data link management and the physical transmission of data on the media. Data-link management protocols take the packets from IP and format them to be transmitted over the media. The standards and protocols for the physical media govern how the signals are sent over the media and how they are interpreted by the receiving clients. Transceivers on the network interface cards implement the appropriate standards for the media that is being used.

Front 43

Explain "Technology Independent Protocols"

Back 43

Because protocols specify ONLY network functionality, and NOT the underlining technology, different types of technologies can utilize the same protocol.

Front 44

Define: Layered Model

Back 44

A layered model depicts the operation of the protocols occurring within each layer, as well as the interaction with the layers above and below it.

Front 45

What are the four benefits of using a Layered Model to describe network protocols and operations?

Hint : A.F.P.P

Back 45

1. Assists in protocol design, because protocols that operate at a specific layer have defined information that they act upon and a defined interface to the layers above and below.

2. Fosters competition because products from different vendors can work together.

3. Prevents technology or capability changes in one layer from affecting other layers above and below.

4. Provides a common language to describe networking functions and capabilities.

Front 46

What are the two basic types of networking models?

Back 46

Protocol Models and Reference Models

Front 47

Define : Protocol Model

Back 47

A model which describes the functions that occur at each layer

Front 48

Define: Reference Model

Back 48

Provides a common reference for maintaining consistency within all types of network protocols and services. The OSI is an example of a reference model.

Front 49

Which model is formerly known as the "Internet Model?"

Back 49

The TCP/IP model.

Front 50

Define: Open Standard

Back 50

Not proprietary

Front 51

True or False

The TCP/IP model is not an open standard.

Back 51

False

Front 52

In the TCP/IP model, what are the seven steps for a complete communication process?

Hint : C.S.G.T.R.D.P.

Back 52

1. Creation of data at the Application layer of the originating source end device

2. Segmentation and encapsulation of data as it passes down the protocol stack in the source end device

3. Generation of the data onto the media at the Network Access layer of the stack

4. Transportation of the data through the internetwork, which consists of media and any intermediary devices

5. Reception of the data at the Network Access layer of the destination end device

6. Decapsulation and reassembly of the data as it passes up the stack in the destination device

7. Passing this data to the destination application at the Application layer of the destination end device

Front 53

Define: Encapsulation

Back 53

The process of inputing data in a particular protocol header.

Front 54

Define : Protocol Data Unit (PDU)

Back 54

A term used to describe data packets as they move from one protocol layer to another.

Front 55

List the order of PDUs, from top to bottom, as it travels down the protocol stack.

Back 55

Data, Segment, Packet, Frame, Bits

Front 56

Which PDU is associated with the Application Layer?

Back 56

Data

Front 57

Which PDU is associated with the Transport layer?

Back 57

Segment

Front 58

Which PDU is associated with the Internetwork Layer?

Back 58

Packet

Front 59

Which PDU is associated with the Network Access Layer?

Back 59

Frame

Front 60

Which PDU is associated with the Physical Layer?

Back 60

Bits

Front 61

Explain the process of sending and receiving data packets across a protocol stack.

Back 61

1. The Application layer protocol begins the process by delivering data to the Transport layer.

2. There the application data is broken into TCP segments. Each TCP segment is given a label, called a header, containing information about which process running on the destination computer should receive the message. It also contains the information to enable the destination process to reassemble the data back to its original format.

3. The Transport layer encapsulates the data within the segment and sends it to the Internet layer, where the IP protocol is implemented. Here the entire TCP segment is encapsulated within an IP packet, which adds another label, called the IP header. The IP header contains source and destination host IP addresses, as well as information necessary to deliver the packet to its corresponding destination process.

4. Next, the IP packet is sent to the Network Access layer Ethernet protocol where it is encapsulated within a frame header and trailer. Each frame header contains a source and destination physical address. The physical address uniquely identifies the devices on the local network. The trailer contains error checking information.

5. Finally the bits are encoded onto the Ethernet media by the server NIC.

6. This process is reversed at the receiving host. The data is decapsulated as it moves up the stack toward the end user application.

Front 62

True of False

The OSI model is a reference model.

Back 62

True

Front 63

From top to bottom, what are the seven layers of the OSI Model?

Back 63

Application, Presentation, Session, Transport, Network, Data Link, Physical.

Front 64

Define: Application Layer

Back 64

Performs services for the applications used by end users.

Front 65

Define: OSI Presentation Layer

Back 65

Provides data format information to the application layer.

For example, the presentation layer informs the application layer whether there is encryption, or whether it is a .jpg picture.

Front 66

Define: OSI Session Layer

Back 66

Manages sessions between users.

For example, the session layer synchronize multiple web sessions of voice and video data in a web conference.

Front 67

Define: OSI Transport Layer

Back 67

Defines data segments and numbers them at the source, transfers the data, and reassembles the data at the destination.

Other functions include acknowledgement, error recovery, and sequencing.

TCP and UDP are associated with this layer.

Front 68

Define: OSI Network Layer

Back 68

Creates and addresses packets for end-to-end delivery to other devices across a network.

Front 69

Define: OSI Data Link Layer

Back 69

Creates and addresses frames for host-to-host delivery on the local LANs and between WAN devices.

Front 70

Define: OSI Physical Layer

Back 70

Defines media specifications, and transmits binary data over media between devices.

Front 71

What are the key parallels between the OSI and TCP/IP models?

Back 71

The Transport and Network Layers.

Front 72

Which identifiers do the Upper Layers use?

Back 72

Encoded Application Data

Front 73

Which identifiers does the Transport Layer use?

Back 73

Destination and Source Port number

Front 74

Which identifiers does the Network Layer use?

Back 74

Destination and Source Logical Network Address

Front 75

Which identifiers does the Data Link Layer use?

Back 75

Destination and Source Physical Address.

Front 76

Which identifiers does the Physical Layer use?

Back 76

Timing and synchronization bits.

Front 77

During the process of encapsulation, address identifiers are added to the data as it travels down the protocol stack on the source host.

Explain the multiple layers of addressing which ensure its delivery.

Back 77

The first identifier, the host physical address, is contained in the header of the Layer 2 PDU, called a frame. Layer 2 is concerned with the delivery of messages on a single local network. The Layer 2 address is unique on the local network and represents the address of the end device on the physical media. In a LAN using Ethernet, this address is called the Media Access Control (MAC) address.

When two end devices communicate on the local Ethernet network, the frames that are exchanged between them contain the destination and source MAC addresses.

Once a frame is successfully received by the destination host, the Layer 2 address information is removed as the data is decapsulated and moved up the protocol stack to Layer 3.

Front 78

At the boundary of each local network, which intermediary device, decapsulates the frame to read the destination host address contained in the header of the packet, the Layer 3 PDU.

Back 78

The Router

Front 79

Explain the process of how the layer 3 protocol moves data from one local network to another local network within an internetwork.

Back 79

In the TCP/IP protocol suite, every IP host address contains information about the network where the host is located.

At the boundary of each local network, an intermediary network device, usually a router, decapsulates the frame to read the destination host address contained in the header of the packet, the Layer 3 PDU.

Routers use the network identifier portion of this address to determine which path to use to reach the destination host.

Once the path is determined, the router encapsulates the packet in a new frame and sends it on its way toward the destination end device.

When the frame reaches its final destination, the frame and packet headers are removed and the data moved up to Layer 4.

Front 80

Explain the process of how layer 4 directs data to the proper conversation.

Back 80

Each application or service is represented at Layer 4 by a port number. A unique dialogue between devices is identified with a pair of Layer 4 source and destination port numbers that are representative of the two communicating applications.

When the data is received at the host, the port number is examined to determine which application or process is the correct destination for the data.

Front 81

Describe the structure of a network, including the devices and media that are necessary for successful communications.

Back 81

Data networks are systems of end devices, intermediary devices, and the media connecting the devices, which provide the platform for the human network.

Front 82

Explain the function of protocols in network communications.

Back 82

Devices, and the services that operate on them, can interconnect in a global and user-transparent way because they comply with rules and protocols.

Front 83

Explain the advantages of using a layered model to describe network functionality.

Back 83

The use of layered models as abstractions means that the operations of network systems can be analyzed and developed to cater the needs of future communication services.

Front 84

Describe the role of each layer in two recognized network models: The TCP/IP model and the OSI model.

Back 84

The most widely-used networking models are OSI and TCP/IP. Associating the protocols that set the rules of data communications with the different layers is useful in determining which devices and services are applied at specific points as data passes across LANs and WANs.

Applying models allows various individuals, companies, and trade associations to analyze current networks and plan the networks of the future.

Front 85

Describe the importance of addressing and naming schemes in network communications.

Back 85

As it passes down the stack, data is segmented into pieces and encapsulated with addresses and other labels. The process is reversed as the pieces are decapsulated and passed up the destination protocol stack.

Without proper addressing and naming schemes, conversation between network devices would be impossible.