study guide for CH2 CCNA1

SEMESTER 1 CHAPTER 2
Communicating over the Network V 4.0

2.0.1
What are the five aspects of the information network we will focus on in this course?
1-Devices that make up the network
2-Media that connect the devices
3-Messages that are carried across the network
4-Rules and processes that govern network communications
5-Tools and commands for constructing and maintaining networks
2.1.1
What are the three elements of communication?
1-message source, or sender
2-the destination, or receiver
3-a channel

What is the definition of the term network for this course? refers to data or information networks capable of carrying many different types of communications, including traditional computer data, interactive voice, video, and entertainment products.
2.1.2
What would happen to the network if a message was sent as one massive continuous stream of bits? it would mean that no other device would be able to send or receive messages on the same network while this data transfer was in progress. Also these large streams of data would result in significant delays. Further, if a link in the interconnected network infrastructure failed during the transmission, the complete message would be lost and have to be retransmitted in full.

Define segmentation of messages division of the data stream into smaller pieces.

What are the 2 advantages of segmentation?
1-many different conversations can be interleaved on the network.( multiplexing.)
2-increase the reliability of network communications.

What is multiplexing?
The process used to interleave the pieces of separate conversations together on the network.
2.1.3
What is hardware on a network?
Devices and media such as a laptop, a PC, a switch, or the cabling.
2.1.4
What are end devices on a network?
1-Computers (work stations, laptops, file servers, web servers)
2-Network printers
3-VoIP phones
4-Security cameras
5-Mobile handheld devices (such as wireless barcode scanners, PDAs)

What is the definition of a host?
A device that can give the source or destination of a message transmitted over the network. In order to distinguish one host from another.

What is the definition of a server? hosts that have software installed that enables them to provide information and services.

What is the definition of a client?
A computer system that accesses a server on another computer remotely by accessing the network.
2.1.5
List examples of intermediary devices.
1-Network Access Devices (Hubs, switches, and wireless access points)
2-Internetworking Devices (routers)
3-Communication Servers and Modems
4-Security Devices (firewalls)

List examples of process that intermediary devices perform.
1-Regenerate and retransmit data signals
2-Maintain information about what pathways exist through the network and internetwork
3-Notify other devices of errors 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
2.1.6
What are the 3 primary types of media used in modern networks?
1-Metallic wires within cables
2-Glass or plastic fibers (fiber optic cable)
3-Wireless transmission

What criteria should be used to select network media?
1-The distance the media can successfully carry a signal.
2-The environment in which the media is to be installed.
3-The amount of data and the speed at which it must be transmitted.
4-The cost of the media and installation
2.2.1
What are the ways in which network infrastructure can vary?
1-The size of the area covered
2-The number of users connected
3-The number and types of services available

What is the definition of a LAN?
A local network, or a group of interconnected local networks that are under the same administrative control.
2.2.2
What is the definition of a WAN?
Is a network that connect LANs networks which are separated by geographic distance and is called wide area network.
2.2.3
What is an internetwork?
A global mesh of interconnected networks (internetworks) meets these human communication needs.

What is an intranetwork? a private connection of LANs and WANs that belongs to an organization, and is designed to be accessible only by the organization's members, employees, or others with authorization.
2.2.4.1
Define a NIC
Network Interface Card provides the physical connection to the network at the PC or other host device.

Define a physical port
A connector or outlet on a networking device where the media is connected to a host or other networking device.

Define an interface
Specialized ports on an internetworking device that connect to individual networks.
2.2.4.2
Complete the Packet Tracer Lab and save your results

2.2.5
You can skip this lab

2.3.1
What are the 3 layers of protocols described?
1-content
2-rules
3-physical
2.3.2
What process do networking layer protocol suites describe?
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

What is proprietary? that one company or vendor controls the definition of the protocol and how it functions.
2.3.3
What does the use of standards and protocols provide? ensures that products from different manufacturers can work together for efficient communications.
2.3.4
What is an application protocol? is a common protocol that governs the way that a web server and a web client interact.(HTTP).

What is a Transport Protocol? the transport protocol that manages the individual conversations between web servers and web clients.(TCP).

What is the Internetwork Protocol s 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.(IP).

What is the Network Access Protocol?
Network access protocols describe two primary functions, data link management and the physical transmission of data on the media.
2.3.5
What do networking protocols describe? describe the functions that occur during network communications.
2.4.1
What are the benefits of using a layered model to describe networking?
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.
2.4.2
What are the two basic types of networking models? protocol models and reference models.

What are the two primary models used when describing networking?
TCP/IP and OSI models
2.4.3
What is done at the Application Layer?
Represent data to the user, encoding and dialog control.

What is done at the Transport Layer?
Support communication between diverse devices across diverse networks.

What is done at the Internet Layer?
Determines the best path through the network.

What is done at the Network Access Layer?
Control the hardware and media that make up the network.
2.4.4
What are the seven steps in a complete communication process?
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
2.4.5
What is the PDU for the application layer?
Data

What is the Transport Layer PDU?
Segment

What is the PDU for the Internet Layer?
Packet

What is the PDU for the Network Access Layer?
Frame

What PDU is used when physically transporting the information over the medium?
Bits
2.4.6.1
How is the protocol stack processed when sending information? the protocol stack on a host operates from top to bottom.
2.4.6.2
What is the process use at the receiving end called?
Its operates from the bottom to the top
2.4.7
What are the seven layers of the OSI Model?
1-physical. 2-data link. 3-network. 4-transport. 5-session. 6-presentation. 7-application
2.4.8
Which Layers of the OSI Model parallel with the TCP/IP Model?
Layers 3 and 4 for the OSI model with layers 2 and 3 for the TCP/IP model.
2.5.1
What does the physical layer do?
Timing and synchronization bits.

What addresses does the data link layer use?
Destination and sources physical address.

What address does the network layer use?
Destination and sources logical network address.

What does the transport layer use?
Destination and sources process number (ports).

What do the upper layers use?
Encoded application data.
2.5.2
What is the PDU for Layer 2 called
Frame

What is the layer 2 address called?
Media Access Control (MAC) address.

What happens after the frame has reached its’ destination?
Layer 2 address information is removed as the data is decapsulated and moved up the protocol stack to Layer 3.
2.5.3
What are layer 3 devices primarily designed for? identifiers that enable intermediary network devices to locate hosts on different networks

What address is used at Layer 3?
IP address

What is the PDU of the Layer 3 information?
Routers use the network identifier portion of this address to determine which path to use to reach the destination host.

Which device decapsulates the frame at the edge of a network?
Router

What does a router do? decapsulates the frame to read the destination host address contained in the header of the packet, the Layer 3 PDU

What happens when the frame reaches the end device? the frame and packet headers are removed and the data moved up to Layer 4
2.5.4
What does the information in the frame provide at Layer 4? identify the specific process or service running on the destination host device that will act on the data being delivered. Hosts, whether they are clients or servers on the Internet, can run multiple network applications simultaneously.

How is each application or service represented at Layer 4?
Each application or service is represented at Layer 4 by a port number.
2.5.5
The movie is pretty good if you can download it.