SEMESTER 1 CHAPTER2
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? / Devices that make up the network
Media that connect the devices
Messages that are carried across the network
Rules and processes that govern network communications
Tools and commands for constructing and maintaining networks
2.1.1 / What are the three elements of communication? / Sender, Receiver, Chanell
What is the definition of the term network for this course? / 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? / no other device would be able to send or receive messages on the same network while this data transfer was in progress
Define segmentation of messages / division of the data stream into smaller pieces
What are the 2 advantages of segmentation? / many different conversations can be interleaved on the network
segmentation can increase the reliability of network communications
What is multiplexing? / process used to interleave the pieces of separate conversations together on the network
2.1.3 / What is hardware on a network? / the visible components of the network platform
2.1.4 / What are end devices on a network? / Computers (work stations, laptops, file servers, web servers)
Network printers
VoIP phones
Security cameras
Mobile handheld devices (such as wireless barcode scanners, PDAs)
What is the definition of a host? / either the source or destination of a message transmitted over the network
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? / hosts that have software installed that enables them to request and display the information obtained from the server
2.1.5 / List examples of intermediary devices. / Network Access Devices (Hubs, switches, and wireless access points)
Internetworking Devices (routers)
Communication Servers and Modems
Security Devices (firewalls)
List examples of process that intermediary devices perform. / Regenerate and retransmit data signals
Maintain information about what pathways exist through the network and internetwork
Notify other devices of errors and communication failures
Direct data along alternate pathways when there is a link failure
Classify and direct messages according to QoS priorities
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? / Metallic wires within cables
Glass or plastic fibers (fiber optic cable)
Wireless transmission
What criteria should be used to select network media? / The distance the media can successfully carry a signal.
The environment in which the media is to be installed.
The amount of data and the speed at which it must be transmitted.
The cost of the media and installation
2.2.1 / What are the ways in which network infrastructure can vary? / The size of the area covered
The number of users connected
The number and types of services available
What is the definition of a LAN? / individual network usually spans a single geographical area, providing services and applications to people within a common organizational structure
2.2.2 / What is the definition of a WAN? / networks that connect LANs in geographically separated locations
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 / 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? / Content Layer, Rules Layer, Physical Layer
2.3.2 / What process do networking layer protocol suites describe? / The format or structure of the message
The process by which networking devices share information about pathways with other networks
How and when error and system messages are passed between devices
The setup and termination of data transfer sessions
What is proprietary? / 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? / products from different manufacturers can work together for efficient communications
2.3.4 / What is an application protocol? / defines the content and formatting of the requests and responses exchanged between the client and server
What is a Transport Protocol? / manages the individual conversations between web servers and web clients
What is the Internetwork Protocol / 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.
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? / the functions that occur during network communications
2.4.1 / What are the benefits of using a layered model to describe networking? / 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.
Fosters competition because products from different vendors can work together.
Prevents technology or capability changes in one layer from affecting other layers above and below.
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
2.4.3 / What is done at the Application Layer? / Represents the data to the user plus encoding and dialog control
What is done at the Transport Layer? / Supports communication between diverse devices across diverse neworks
What is done at the Internet Layer? / Determines the best path through the network
What is done at the Network Access Layer? / Controls the hardware devices 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? / Top to bottom
2.4.6.2 / What is the process use at the receiving end called? / Decapsulation
2.4.7 / What are the seven layers of the OSI Model? / Application, Presentation, Session, Transport, Network, Data Link, Physical
2.4.8 / Which Layers of the OSI Model parallel with the TCP/IP Model? / Application, Presentation, Session-Application
Transport-Transport
Internet-Network
Data Link, Physical-Network Access
2.5.1 / What does the physical layer do? / Timing and synchronization of bits
What addresses does the data link layer use? / Destination and source physical address
What address does the network layer use? / Destination and source logical address
What does the transport layer use? / Destination and source 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? / MAC address
What happens after the frame has reached its’ destination? / the 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? / to move data from one local network to another local network within an internetwork
What address is used at Layer 3? / IP address
What is the PDU of the Layer 3 information? / Packet
Which device decapsulates the frame at the edge of a network? / Router
What does a router do? / use the network identifier portion of this address to determine which path to use to reach the destination host
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? / identifies the specific process or service running on the destination host device that will act on the data being delivered
How is each application or service represented at Layer 4? / Port number
2.5.5 / The movie is pretty good if you can download it.
2.6.1 / Complete the Packet Tracer Lab and save your network when completed. E-mail the file
2.6.2 / Complete the Packet Tracer Lab and save your network when completed. E-mail the file
2.7.1.3 / **Extra Credit***
Complete this Packet Tracer Lab, save the file, and email it to me.

* What are the intermediary devices? What are their functions?

  • Processes running on the intermediary network devices perform these functions:
  • Regenerate and retransmit data signals
  • Maintain information about what pathways exist through the network and internetwork
  • Notify other devices of errors and communication failures
  • Direct data along alternate pathways when there is a link failure
  • Classify and direct messages according to QoS priorities
  • Permit or deny the flow of data, based on security settings
  • Examples of intermediary network devices are:
  • Network Access Devices (Hubs, switches, and wireless access points)
  • Internetworking Devices (routers)
  • Communication Servers and Modems
  • Security Devices (firewalls)

* What are the end devices? What are their functions?

  • End devices are referred to as hosts.
  • A host device is either the source or destination.
  • A host can act as a client, a server, or both.
  • Some examples of end devices are:
  • Computers (work stations, laptops, file servers, web servers)
  • Network printers
  • VoIP phones
  • Security cameras
  • Mobile handheld devices (such as wireless barcode scanners, PDAs)

* What is LAN? What are the characteristics of LAN?

  • An individual network usually spans a single geographical area, providing services and applications to people within a common organizational structure, such as a single business, campus or region.
  • A LAN is usually administered by a single organization.
  • The administrative control that governs the security and access control policies are enforced on the network level.

* What is WAN? What are the characteristics of WAN?

  • When a company or organization has locations that are separated by large geographical distances, it may be necessary to use a telecommunications service provider (TSP) to interconnect the LANs at the different locations.
  • These networks that connect LANs in geographically separated locations are referred to as Wide Area Networks (WANs).

* What is the “multiplexing”?

  • Sending smaller individual pieces from source to destination, many different conversations can be interleaved on the network.
  • The process used to interleave the pieces of separate conversations together on the network is called multiplexing.

* What are the definitions of “network protocols”?

  • define the structure of layer specific PDU's
  • outline the functions necessary for communications between layers
  • require layer dependent encapsulations

* Networking protocol suites describe processes such as:

  • The format or structure of the message
  • The method by which networking devices share information about pathways with other networks
  • How and when error and system messages are passed between devices
  • The setup and termination of data transfer sessions

What are the functions of encapsulation?

  • identifies pieces of data as part of the same communication
  • ensures that data pieces can be directed to the correct receiving end device
  • enables the reassembly of complete messages

* What is PDU?

  • The form that a piece of data takes at any layer is called a Protocol Data Unit (PDU).
  • During encapsulation, each succeeding layer encapsulates the PDU that it receives from the layer above in accordance with the protocol being used.
  • At each stage of the process, a PDU has a different name to reflect its new appearance.
  • Data - The general term for the PDU used at the Application layer
  • Segment - Transport Layer PDU
  • Packet - Internetwork Layer PDU
  • Frame - Network Access Layer PDU
  • Bits - A PDU used when physically transmitting data over the medium

* What is “encapsulation”? What are the purposes of encapsulation?

- Drippy Sweet Pancakes For Breakfast

- You need to know the name of each PDU during the encapsulation process.

- You need to know the information added to each stage.

* What is the purpose of the layer 4(or transport layer) segment headers?

  • The transport layer: The application data is broken into TCP segments.
  • Each TCP segment is given a label, called a header, containing information about which processes(or services) running on the destination computer should receive the message.

* What is the purpose of the layer 3(or internet layer, or network layer) packet headers?

  • The Internet layer: 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 IP addresses. .

* What is the purpose of the layer 2 (or network access layer, or data link layer) frame headers and the trailers?

  • The Network Access layer: Ethernet protocol where it is encapsulated within a frame header and trailer.
  • Frame header contains source and destination physical address.
  • The trailer contains error checking information.
  • Finally the bits are encoded onto the Ethernet media by the server NIC.

* What is “logical address”?

  • Another name for logical address is IP address

* What is “physical address”?

  • In a LAN using Ethernet, this address is called the Media Access Control (MAC) address.

* You need to know the name of OSI models?

-Please Do Not Throw Sausage Pizza Away

- Can you list the primary function of each layer?

* You need to know the name of TCP/IP models?

-Never Ingest Tainted Apple

- Can you list the primary function of each layer?

* You need to know the side-by-side comparison of both models (which layer mapped to which layer).

OSI
Layer # / ISO Layer
Name / TCP/IP
# / TCP/IP layer Name / Encapsulation
Units / Devices or
Components / TCP/IP Protocols / Keywords/Description
7 / Application
(Away) / 4 / Application
(Apple) / data / PC / FTP, HTTP, POP3, IMAP, telnet, SMTP, DNS, TFTP / Network services for application processes, such as file, print, messaging, database services
6 / Presentation
(Pizza) / data / Standard interface to data for the application layer. MIME encoding, data encryption, conversion, formatting, compression
5 / Session
(Sausage) / data
(Drippy) / Interhost communication. Establishes, manages and terminates connection between applications
4 / Transport
(Throw) / 3 / Transport
(Tainted) / segments
(Sweet) / TCP, UDP / End-to-end connections and reliability. Segmentation/desegmentation of data in proper sequence. Flow control
3 / Network
(not) / 2 / Internet
(Ingest) / packets
(Pancakes) / router / IP / Logical addressing and path determination. Routing. Reporting delivery errors
2 / Data Link
(DO) / 1 / Network Access
(Never) / frames
(For) / bridge, switch, NIC / Physical addressing and access to media. Two sublayers: Logical Link Control (LLC) and Media Access Control (MAC)
1 / Physical
(Please) / bits
(Breakfast) / repeater, hub, tranciever / Binary transmission signals and encoding. Layout of pins, voltages, cable specifications, modulation