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Introduction to Networks > 03_Protocols and Models > Flashcards

03_Protocols and Models Flashcards

1
Q

The Rules

A

Describe the types of rules that are necessary to successfully communicate.

All communication methods have three elements in common: message source (sender), message destination (receiver), and channel. Sending a message is governed by rules called protocols. Protocols must include: an identified sender and receiver, common language and grammar, speed and timing of delivery, and confirmation or acknowledgment requirements. Common computer protocols include these requirements: message encoding, formatting and encapsulation, size, timing, and delivery options. Encoding is the process of converting information into another acceptable form, for transmission. Decoding reverses this process to interpret the information. Message formats depend on the type of message and the channel that is used to deliver the message. Message timing includes flow control, response timeout, and access method. Message delivery options include unicast, multicast, and broadcast.

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2
Q

Protocols

A
  • Explain why protocols are necessary in network communication.
  • Protocols must account for the following requirements to successfully deliver a message that is understood by the receiver:
  • An identified sender and receiver
  • Common language and grammar
  • Speed and timing of delivery
  • Confirmation or acknowledgment requirements

Protocols are implemented by end-devices and intermediary devices in software, hardware, or both. A message sent over a computer network typically requires the use of several protocols, each one with its own functions and format. Each network protocol has its own function, format, and rules for communications. The Ethernet family of protocols includes IP, TCP, HTTP, and many more. Protocols secure data to provide authentication, data integrity, and data encryption: SSH, SSL, and TLS. Protocols enable routers to exchange route information, compare path information, and then to select the best path to the destination network: OSPF and BGP. Protocols are used for the automatic detection of devices or services: DHCP and DNS. Computers and network devices use agreed-upon protocols that provide the following functions: addressing, reliability, flow control, sequencing, error-detection, and application interface.

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3
Q

Protocol Suites

A

Explain the purpose of adhering to a protocol suite.

A protocol suite is a group of inter-related protocols necessary to perform a communication function. A protocol stack shows how the individual protocols within a suite are implemented. Since the 1970s there have been several different protocol suites, some developed by a standards organization and others developed by various vendors. TCP/IP protocols are available for the application, transport, and internet layers. TCP/IP is the protocol suite used by today’s networks and internet. TCP/IP offers two important aspects to vendors and manufacturers: open standard protocol suite, and standards-based protocol suite. The TCP/IP protocol suite communication process enables such processes as a web server encapsulating and sending a web page to a client, as well as the client de-encapsulating the web page for display in a web browser.

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4
Q

Standards Organizations

A

Explain the role of standards organizations in establishing protocols for network interoperability.

Open standards encourage interoperability, competition, and innovation. Standards organizations are usually vendor-neutral, non-profit organizations established to develop and promote the concept of open standards. Various organizations have different responsibilities for promoting and creating standards for the internet including: ISOC, IAB, IETF, and IRTF. Standards organizations that develop and support TCP/IP include: ICANN and IANA. Electronic and communications standards organizations include: IEEE, EIA, TIA, and ITU-T.

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5
Q

Reference Models

A

Explain how the TCP/IP model and the OSI model are used to facilitate standardization in the communication process.

The two reference models that are used to describe network operations are OSI and TCP/IP.

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6
Q

Data Encapsulation

A

Explain how data encapsulation allows data to be transported across the network.

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7
Q

Data Access

A

Explain how local hosts access local resources on a network.

The network and data link layers are responsible for delivering the data from the source device to the destination device. Protocols at both layers contain a source and destination address, but their addresses have different purposes:

Network layer source and destination addresses - Responsible for delivering the IP packet from the original source to the final destination, which may be on the same network or a remote network.
Data link layer source and destination addresses - Responsible for delivering the data link frame from one network interface card (NIC) to another NIC on the same network.
The IP addresses indicate the original source IP address and final destination IP address. An IP address contains two parts: the network portion (IPv4) or Prefix (IPv6) and the host portion (IPv4) or Interface ID (IPv6). When the sender and receiver of the IP packet are on the same network, the data link frame is sent directly to the receiving device. On an Ethernet network, the data link addresses are known as Ethernet Media Access Control (MAC) addresses. When the sender of the packet is on a different network from the receiver, the source and destination IP addresses will represent hosts on different networks. The Ethernet frame must be sent to another device known as the router or default gateway.

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8
Q

Message source (sender)

A

Message sources are people, or electronic devices, that need to send a message to other individuals or devices.

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9
Q

Message Destination (receiver)

A

The destination receives the message and interprets it.

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10
Q

Channel

A

This consists of the media that provides the pathway over which the message travels from source to destination.

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11
Q

Common computer protocols include the following requirements:

A
  • Message encoding
  • Message formatting and encapsulation
  • Message size
  • Message timing
  • Message delivery options
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12
Q

Message encoding

A

Encoding is the process of converting information into another acceptable form, for transmission. Decoding reverses this process to interpret the information.

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13
Q

Message formatting and encapsulation

A

An envelope has the address of the sender and receiver, each located at the proper place on the envelope. If the destination address and formatting are not correct, the letter is not delivered.

The process of placing one message format (the letter) inside another message format (the envelope) is called encapsulation. De-encapsulation occurs when the process is reversed by the recipient and the letter is removed from the envelope.

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14
Q

Message size

A

Another rule of communication is message size.

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15
Q

Message timing

A
  • Flow Control - This is the process of managing the rate of data transmission. Flow control defines how much information can be sent and the speed at which it can be delivered. For example, if one person speaks too quickly, it may be difficult for the receiver to hear and understand the message. In network communication, there are network protocols used by the source and destination devices to negotiate and manage the flow of information.
  • Response Timeout - If a person asks a question and does not hear a response within an acceptable amount of time, the person assumes that no answer is coming and reacts accordingly. The person may repeat the question or instead, may go on with the conversation. Hosts on the network use network protocols that specify how long to wait for responses and what action to take if a response timeout occurs.
  • Access method - This determines when someone can send a message. Click Play in the figure to see an animation of two people talking at the same time, then a “collision of information” occurs, and it is necessary for the two to back off and start again. Likewise, when a device wants to transmit on a wireless LAN, it is necessary for the WLAN network interface card (NIC) to determine whether the wireless medium is available.
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16
Q

Message Delivery Options

A
  • Unicast - Information is being transmitted to a single end device.
  • Multicast - Information is being transmitted to a one or more end devices.
  • Broadcast - Information is being transmitted to all end devices.
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17
Q

What is the process of converting information into the proper form for transmission?

A

encoding

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18
Q

Which step of the communication process is concerned with properly identifying the address of the sender and receiver?

A

formatting

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19
Q

Which three are components of message timing? (Choose three.)

A
  • flow control
  • access method
  • response timeout
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20
Q

Which delivery method is used to transmit information to one or more end devices, but not all devices on the network?

A

multicast

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21
Q

Network Communications Protocols

A

Protocols enable two or more devices to communicate over one or more networks. The Ethernet family of technologies involves a variety of protocols such as IP, Transmission Control Protocol (TCP), HyperText Transfer Protocol (HTTP), and many more.

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22
Q

Network Security Protocols

A

Protocols secure data to provide authentication, data integrity, and data encryption. Examples of secure protocols include Secure Shell (SSH), Secure Sockets Layer (SSL), and Transport Layer Security (TLS).

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23
Q

Routing Protocols

A

Protocols enable routers to exchange route information, compare path information, and then to select the best path to the destination network. Examples of routing protocols include Open Shortest Path First (OSPF) and Border Gateway Protocol (BGP).

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24
Q

Service Discovery Protocols

A

Protocols are used for the automatic detection of devices or services. Examples of service discovery protocols include Dynamic Host Configuration Protocol (DHCP) which discovers services for IP address allocation, and Domain Name System (DNS) which is used to perform name-to-IP address translation.

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25
Q

Computers and network devices use agreed-upon protocols to communicate

A
  • Addressing
  • Reliability
  • Flow control
  • Sequencing
  • Error Detection
  • Application Interface
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26
Q

Addressing

A

This identifies the sender and the intended receiver of the message using a defined addressing scheme. Examples of protocols that provide addressing include Ethernet, IPv4, and IPv6.

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27
Q

Reliability

A

This function provides guaranteed delivery mechanisms in case messages are lost or corrupted in transit. TCP provides guaranteed delivery.

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28
Q

Flow control

A

This function ensures that data flows at an efficient rate between two communicating devices. TCP provides flow control services.

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29
Q

Sequencing

A

This function uniquely labels each transmitted segment of data. The receiving device uses the sequencing information to reassemble the information correctly. This is useful if the data segments are lost, delayed or received out-of-order. TCP provides sequencing services.

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30
Q

Error Detection

A

This function is used to determine if data became corrupted during transmission. Various protocols that provide error detection include Ethernet, IPv4, IPv6, and TCP.

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31
Q

Application Interface

A

This function contains information used for process-to-process communications between network applications. For example, when accessing a web page, HTTP or HTTPS protocols are used to communicate between the client and server web processes.

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32
Q

Hyptertext Transfer Protocol (HTTP)

A

This protocol governs the way a web server and a web client interact. HTTP defines the content and formatting of the requests and responses that are exchanged between the client and server.

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33
Q

Transmission Control Protocol (TCP)

A

This protocl manages the individual conversations. TCP is responsible for guaranteeing the reliable delivery of the information and managing flow control between the end devices

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34
Q

Internet Protocol (IP)

A

This protocol is responsible for delivering messages from the sender to the receiver. IP is used by routers to forward the messages across multiple networks

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35
Q

Ethernet

A

This protocol is responsible for the delivery of messages from one NIC to another NIC on the same Ethernet local area network (LAN).

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36
Q

BGP and OSPF are examples of which type of protocol?

A

routing

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37
Q

Which two protocols are service discovery protocols? (Choose two.)

A
  • DNS

- DHCP

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38
Q

What is the purpose of the sequencing function in network communication?

A

to uniquely label transmitted segments of data for proper reassembly by the receiver

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39
Q

This protocol is responsible for guaranteeing the reliable delivery of information.

A

TCP

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40
Q

Internet Protocol Suite or TCP/IP

A

This is the most common and relevant protocol suite used today

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41
Q

Open Systems Interconnection (OSI) protocols

A

This is a family of protocols developd jointly in 1977 by the International Organization for Standardization (ISO) and the International Telecommunications Union (ITU). The OSI protocol also included a seven-layer model called the OSI reference model. The OSI reference model categorizes the functions of its protocols. Today OSI is mainly known for its layered model. The OSI protocols have largely been replaced by TCP/IP

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42
Q

AppleTalk

A

A short-lived proprietary protocol suite released by Apple Inc. in 1985 for Apple devices. In 1995, Apple adopted TCP/IP to replace AppleTalk

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43
Q

Novell NetWare

A

A short-lived proprietary protocol suite and network operating system developed by Novell Inc. in 1983 using the IPX network protocol. In 1995, Novell adopted

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44
Q

TCP/IP Protocol Example

A

TCP/IP protocols are available for the application, transport, and internet layers. There are no TCP/IP protocols in the network access layer. The most common network access layer LAN protocols are Ethernet and WLAN (wireless LAN) protocols. Network access layer protocols are responsible for delivering the IP packet over the physical medium.

Web Server Internet
(Layer Name | Protocol Stack)
Application | Hypertext Transfer Protocol (HTTP)
Transport | Transmission Control Protocol (TCP)
Internet | Internet Protocol (IP)
Network Access | Ethernet

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45
Q

TCP/IP Protocol Suite

A

TCP/IP Layers
Application Layer:
- Name System
DNS

  • Host Config
    DHCPv4
    DHCPv6
    SLAAC
  • Email
    SMTP
    POP3
    IMAP
  • File Transfer
    FTP
    SFTP
    TFTP
  • Web Service
    HTTP
    HTTPS
    REST

Transport Layer
- Connection-Oriented
TCP

  • Connectionless
    UDP
Internet Layer:
- Internet Protocol
IPv4
IPv6
NAT
  • Messaging
    ICMPv4
    ICMPv6
    ICMPv6 ND
  • Routing Protocols
    OSPF
    EIGRP
    BGP

Network Access Layer:
- Address Resolution
ARP

  • Data Link Protocols
    Ethernet
    WLAN
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46
Q

TCP/IP has two important aspects for vendors and manufacturers:

A
  • Open standard protocol suite - This means it is freely available to the public and can be used by any vendor on their hardware or in their software
  • Standards-based protocol suite - This means it has been endorsed by the networking industry and approved by a standards organization. This ensures that products from different manufacturers can interoperate successfully.
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47
Q

Application Layer

A

Name System

DNS - Domain Name System. Translates domain names such as cisco.com, into IP addresses.
Host Config

DHCPv4 - Dynamic Host Configuration Protocol for IPv4. A DHCPv4 server dynamically assigns IPv4 addressing information to DHCPv4 clients at start-up and allows the addresses to be re-used when no longer needed.
DHCPv6 - Dynamic Host Configuration Protocol for IPv6. DHCPv6 is similar to DHCPv4. A DHCPv6 server dynamically assigns IPv6 addressing information to DHCPv6 clients at start-up.
SLAAC - Stateless Address Autoconfiguration. A method that allows a device to obtain its IPv6 addressing information without using a DHCPv6 server.
Email

SMTP - Simple Mail Transfer Protocol. Enables clients to send email to a mail server and enables servers to send email to other servers.
POP3 - Post Office Protocol version 3. Enables clients to retrieve email from a mail server and download the email to the client’s local mail application.
IMAP - Internet Message Access Protocol. Enables clients to access email stored on a mail server as well as maintaining email on the server.
File Transfer

FTP - File Transfer Protocol. Sets the rules that enable a user on one host to access and transfer files to and from another host over a network. FTP is a reliable, connection-oriented, and acknowledged file delivery protocol.
SFTP - SSH File Transfer Protocol. As an extension to Secure Shell (SSH) protocol, SFTP can be used to establish a secure file transfer session in which the file transfer is encrypted. SSH is a method for secure remote login that is typically used for accessing the command line of a device.
TFTP - Trivial File Transfer Protocol. A simple, connectionless file transfer protocol with best-effort, unacknowledged file delivery. It uses less overhead than FTP.
Web and Web Service

HTTP - Hypertext Transfer Protocol. A set of rules for exchanging text, graphic images, sound, video, and other multimedia files on the World Wide Web.
HTTPS - HTTP Secure. A secure form of HTTP that encrypts the data that is exchanged over the World Wide Web.
REST - Representational State Transfer. A web service that uses application programming interfaces (APIs) and HTTP requests to create web applications.

48
Q

Transport layer

A

Connection-Oriented

TCP - Transmission Control Protocol. Enables reliable communication between processes running on separate hosts and provides reliable, acknowledged transmissions that confirm successful delivery.
Connectionless

UDP - User Datagram Protocol. Enables a process running on one host to send packets to a process running on another host. However, UDP does not confirm successful datagram transmission.

49
Q

Internet Layer

A

Internet Protocol

IPv4 - Internet Protocol version 4. Receives message segments from the transport layer, packages messages into packets, and addresses packets for end-to-end delivery over a network. IPv4 uses a 32-bit address.
IPv6 - IP version 6. Similar to IPv4 but uses a 128-bit address.
NAT - Network Address Translation. Translates IPv4 addresses from a private network into globally unique public IPv4 addresses.
Messaging

ICMPv4 - Internet Control Message Protocol for IPv4. Provides feedback from a destination host to a source host about errors in packet delivery.
ICMPv6 - ICMP for IPv6. Similar functionality to ICMPv4 but is used for IPv6 packets.
ICMPv6 ND - ICMPv6 Neighbor Discovery. Includes four protocol messages that are used for address resolution and duplicate address detection.
Routing Protocols

OSPF - Open Shortest Path First. Link-state routing protocol that uses a hierarchical design based on areas. OSPF is an open standard interior routing protocol.
EIGRP - EIGRP - Enhanced Interior Gateway Routing Protocol. An open standard routing protocol developed by Cisco that uses a composite metric based on bandwidth, delay, load and reliability.
BGP - Border Gateway Protocol. An open standard exterior gateway routing protocol used between Internet Service Providers (ISPs). BGP is also commonly used between ISPs and their large private clients to exchange routing information.

50
Q

Network Access Layer

A

Address Resolution

ARP - Address Resolution Protocol. Provides dynamic address mapping between an IPv4 address and a hardware address.

Note: You may see other documentation state that ARP operates at the Internet Layer (OSI Layer 3). However, in this course we state that ARP operates at the Network Access layer (OSI Layer 2) because it’s primary purpose is the discover the MAC address of the destination. A MAC address is a Layer 2 address.

Data Link Protocols

Ethernet - Defines the rules for wiring and signaling standards of the network access layer.
WLAN - Wireless Local Area Network. Defines the rules for wireless signaling across the 2.4 GHz and 5 GHz radio frequencies.

51
Q

TCP/IP Communication Process - to view an animation of a web server encapsulating and sending a web page to a client.

A
  1. Data - User Data
  2. TCP - TCP Segment
  3. IP - IP Packet
  4. Ethernet Frame - Ethernet
52
Q

TCP/IP Communication Process - to view an animation of the client receiving, and de-encapsulating the web page for display in the web browser.

A
  1. Ethernet Frame - Ethernet
  2. IP - IP Packet
  3. TCP - TCP Segment
  4. Data - User Data
53
Q

UDP and TCP belong to which layer of the TCP/IP protocol?

A

transport

54
Q

Which two protocols belong in the TCP/IP model application layer?

A
  • DNS

- DHCP

55
Q

Which protocol operates at the network access layer of the TCP/IP model?

A

Ethernet

56
Q

Which of the following are protocols that provide feedback from the destination host to the source host regarding errors in packet delivery? (Choose two.)

A
  • ICMPv4

- ICMPv6

57
Q

A device receives a data link frame with data and processes and removes the Ethernet information. What information would be the next to be processed by the receiving device?

A

IP at the internet layer

58
Q

Which services are provided by the internet layer of the TCP/IP protocol suite? (Choose three.)

A
  • Routing Protocols
  • Messaging
  • Internet Protocol
59
Q

Open Standards

A

Open standards encourage interoperability, competition, and innovation.

60
Q

Internet Society (ISOC)

A

Responsible for promoting the open development and evolution of internet use throughout the world

61
Q

Internet Architecture Board (IAB)

A

Responsible for the overall management and development of internet standards

62
Q

Internet Engineering Task Force (IETF)

A

Develops, updates, and maintains internet and TCP/IP technologies. This includes the process and documents for developing new protocols and updating existing protocols, which are known as Request for Comments (RFC) documents

63
Q

Internet Corporation for Assigned Names and Numbers (ICANN)

A

Based in the US, ICANN coordinates IP address allocation, the management of domain names, and assignment of other information used in TCP/IP protocols

64
Q

Internet Assigned Numbers Authority (IANA)

A

Responsible for overseeing and managing IP address allocation, domain name management, and protocol identifiers for ICANN

65
Q

Institute of Electrical and Electronics Engineers (IEEE, pronounced “I-triple-E”)

A

Organization of electrical engineering and electronics dedicated to advancing technological innovation and creating standards in a wide area of industries including power and energy, healthcare, telecommunications, and networking. Important IEEE networking standards include 802.3 Ethernet and 802.11 WLAN standard. Search the internet for other IEEE network standards.

66
Q

Electronic Industries Alliance (EIA)

A

Organization is best known for its standards relating to electrical wiring, connectors, and the 19-inch racks used to mount networking equipment.

67
Q

Telecommunications Industry Association (TIA)

A

Organization responsible for developing communication standards in a variety of areas including radio equipment, cellular towers, Voice over IP (VoIP) devices, satellite communications, and more.

68
Q

International Telecommunications Union-Telecommunication Standardization Sector (ITU-T)

A

One of the largest and oldest communication standards organizations. The ITU-T defines standards for video compression, Internet Protocol Television (IPTV), and broadband communications, such as a digital subscriber line (DSL).

69
Q

True or false. Standards organizations are usually vendor-neutral.

A

True

70
Q

This standards organization is concerned with the Request for Comments (RFC) documents that specify new protocols and update existing ones.

A

Internet Engineering Task Force (IETF)

71
Q

This standards organization is responsible for IP address allocation and domain name management.

A

Internet Assigned Numbers Authority (IANA)

72
Q

What types of standards are developed by the Electronics Industries Alliance (EIA)?

A

electric wiring and connectors

73
Q

benefits of using a layered model to describe network protocols and operations:

A
  • Assisting 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
  • Fostering competition because products from different vendors can work together
  • Preventing technology or capability changes in one layer from affecting other layers above and below
  • Providing a common language to describe networking functions and capabilities
74
Q

two layered models that are used to describe network operations

A
  • Open System Interconnection (OSI) Reference Model: provides an extensive list of functions and services that can occur at each layer. It also describes the interaction of each layer with the layers directly above and below. The TCP/IP protocols discussed in this course are structured around both the OSI and TCP/IP models.

The OSI model has seven layers:
7 - Application

6 - Presentation

5 - Session

4 - Transport

3 - Network

2 - Data Link

1 - Physical

  • TCP/IP Reference Model: model for internetwork communications was created in the early 1970s and is sometimes referred to as the internet model. This type of model closely matches the structure of a particular protocol suite. The TCP/IP model is a protocol model because it describes the functions that occur at each layer of protocols within the TCP/IP suite.

The TCP/IP model has four layers:
4 - Application

3 - Transport

2 - Internet

1 - Network Access

75
Q

OSI Reference Model

A

7 - Application The application layer contains protocols used for process-to-process communications. (TCP/IP Protocol Suite: HTTP, DNS, DHCP, FTP)

6 - Presentation The presentation layer provides for common representation of the data transferred between application layer services. (TCP/IP Protocol Suite: HTTP, DNS, DHCP, FTP)

5 - Session The session layer provides services to the presentation layer to organize its dialogue and to manage data exchange. (TCP/IP Protocol Suite: HTTP, DNS, DHCP, FTP)

4 - Transport The transport layer defines services to segment, transfer, and reassemble the data for individual communications between the end devices. (TCP/IP Protocol Suite: TCP UDP)

3 - Network The network layer provides services to exchange the individual pieces of data over the network between identified end devices. (TCP/IP Protocol Suite: IPv4, IPv6, ICMPv4, ICMPv6)

2 - Data Link The data link layer protocols describe methods for exchanging data frames between devices over a common media. (TCP/IP Protocol Suite: Ethernet, WLAN, SONET, SDH)

1 - Physical The physical layer protocols describe the mechanical, electrical, functional, and procedural means to activate, maintain, and de-activate physical connections for a bit transmission to and from a network device. (TCP/IP Protocol Suite: Ethernet, WLAN, SONET, SDH)

76
Q

TCP/IP Protocol Model

A

4 - Application Represents data to the user, plus encoding and dialog control. (TCP/IP Protocol Suite: HTTP, DNS, DHCP, FTP)

3 - Transport Supports communication between various devices across diverse networks. (TCP/IP Protocol Suite: TCP UDP)

2 - Internet Determines the best path through the network. (TCP/IP Protocol Suite: IPv4, IPv6, ICMPv4, ICMPv6)

1 - Network Access Controls the hardware devices and media that make up the network. (TCP/IP Protocol Suite: Ethernet, WLAN, SONET, SDH)

77
Q

segmenting messages having two primary benefits:

A

Increases speed - Because a large data stream is segmented into packets, large amounts of data can be sent over the network without tying up a communications link. This allows many different conversations to be interleaved on the network called multiplexing.

Increases efficiency -If a single segment is fails to reach its destination due to a failure in the network or network congestion, only that segment needs to be retransmitted instead of resending the entire data stream.

78
Q

encapsulation process

A

As application data is passed down the protocol stack on its way to be transmitted across the network media, various protocol information is added at each level. This is known as the encapsulation process.

Note: Although the UDP PDU is called datagram, IP packets are sometimes also referred to as IP datagrams.

  • data - the general term for PDU used at the application layer
  • segment - transport layer PDU
  • packet - network layer PDU
  • frame - data link layer PDU
  • bits - physical layer PDU used when physically transmitting data over the medium

the encapsulation process works from top to bottom. At each layer, the upper layer information is considered data within the encapsulated protocol. For example, the TCP segment is considered data within the IP packet.

79
Q

De-encapsulation

A

process is reversed at the receiving host and is known as de-encapsulation. De-encapsulation is the process used by a receiving device to remove one or more of the protocol headers. The data is de-encapsulated as it moves up the stack toward the end-user application.

80
Q

What is the process of dividing a large data stream into smaller pieces prior to transmission?

A

segmentation

81
Q

What is the PDU associated with the transport layer?

A

segment

82
Q

Which protocol stack layer encapsulates data into frames?

A

data link

83
Q

What is the name of the process of adding protocol information to data as it moves down the protocol stack?

A

encapsulation

84
Q

Network layer source and destination addresses

A

Responsible for delivering the IP packet from the original source to the final destination, which may be on the same network or a remote network.

85
Q

Data link layer source and destination addresses

A

Responsible for delivering the data link frame from one network interface card (NIC) to another NIC on the same network.

86
Q

physical

A

timing and synchronization bits

87
Q

data link

A

destination and source physical addresses

88
Q

network

A

destination and source logical network addresses

89
Q

transport

A

destination and source process number (ports)

90
Q

upper layers

A

encoded application data

91
Q

Layer 3

A

An IP address is the network layer, or Layer 3, logical address used to deliver the IP packet from the original source to the final destination

92
Q

The IP packet contains two IP addresses

A
  • Source IP address - The IP address of the sending device, which is the original source of the packet.
  • Destination IP address - The IP address of the receiving device, which is the final destination of the packet.
93
Q

An IP address contains two parts

A
  • Network portion (IPv4) or Prefix (IPv6) - The left-most part of the address that indicates the network in which the IP address is a member. All devices on the same network will have the same network portion of the address.
  • Host portion (IPv4) or Interface ID (IPv6) - The remaining part of the address that identifies a specific device on the network. This portion is unique for each device or interface on the network.

Note: The subnet mask (IPv4) or prefix-length (IPv6) is used to identify the network portion of an IP address from the host portion.

94
Q

communicating with an FTP server on the same IP network

A
  • Source IPv4 address: The IPv4 address of the sending device, the client computer PC1: 192.168.1.110.
  • Destination IPv4 address: The IPv4 address of the receiving device, FTP server: 192.168.1.9.
95
Q

Role of the Data Link Layer Addresses: Same IP Network

A
  • Source MAC address - This is the data link address, or the Ethernet MAC address, of the device that sends the data link frame with the encapsulated IP packet. The MAC address of the Ethernet NIC of PC1 is AA-AA-AA-AA-AA-AA, written in hexadecimal notation.
  • Destination MAC address - When the receiving device is on the same network as the sending device, this is the data link address of the receiving device. In this example, the destination MAC address is the MAC address of the FTP server: CC-CC-CC-CC-CC-CC, written in hexadecimal notation.

Ethernet Media Access Control: When the sender and receiver of the IP packet are on the same network, the data link frame is sent directly to the receiving device. On an Ethernet network, the data link addresses are known as Ethernet Media Access Control (MAC) addresses

96
Q

Role of the Network Layer Addresses

A
  • Source IPv4 address: The IPv4 address of the sending device, the client computer PC1: 192.168.1.110.
  • Destination IPv4 address: The IPv4 address of the receiving device, the server, Web Server: 172.16.1.99.
97
Q

True or false? Frames exchanged between devices in different IP networks must be forwarded to a default gateway.

A

True

98
Q

True or false? The right-most part of an IP address is used to identify the network that a device belongs to.

A

False

99
Q

What is used to determine the network portion of an IPv4 address?

A

subnet mask

100
Q

Which of the following statements are true regarding network layer and data link layer addresses? (Choose three.)

A
  • Network layer addresses are logical and data link addresses are expressed as 12 hexadecimal digits
  • Data link layer addresses are physical and network layer addresses are logical
  • Network layer addresses are either 32 or 128 bits in length
101
Q

What is the order of the two addresses in the data link frame?

A
  • destination MAC, source MAC
102
Q

True or False? Data Link addresses are physical so they never change in the data link frame from source to destination.

A

False

103
Q

Which three acronyms/initialisms represent standards organizations? (Choose three.)

A
  • IEEE
  • IETF
  • IANA
104
Q

What type of communication will send a message to all devices on a local area network?

A

broadcast

105
Q

In computer communication, what is the purpose of message encoding?

A

to convert information to the appropriate form for transmission

106
Q

Which message delivery option is used when all devices need to receive the same message simultaneously?

A

broadcast

107
Q

What are two benefits of using a layered network model? (Choose two.)

A
  • assists in protocol design
  • fosters competition between vendors
  • prevents a technology that functions at one layer from affecting any other layer
  • provides a common language for describing network functionality
  • helps in visualizing interaction between each layer and protocols between each layer
108
Q

What is the purpose of protocols in data communications?

A

providing the rules required for a specific type of communication to occur

109
Q

Which logical address is used for delivery of data to a remote network?

A

destination IP address

110
Q

What is the general term that is used to describe a piece of data at any layer of a networking model?

A

protocol data unit

111
Q

Which two protocols function at the internet layer? (Choose two.)

A
  • IP

- ICMP

112
Q

Which layer of the OSI model defines services to segment and reassemble data for individual communications between end devices?

A

transport

113
Q

Which type of communication will send a message to a group of host destinations simultaneously?

A

multicast

114
Q

What process is used to receive transmitted data and convert it into a readable message?

A

decoding

115
Q

What is done to an IP packet before it is transmitted over the physical medium?

A

It is encapsulated in a Layer 2 frame

116
Q

What process is used to place one message inside another message for transfer from the source to the destination?

A

encapsulation

117
Q

A web client is sending a request for a webpage to a web server. From the perspective of the client, what is the correct order of the protocol stack that is used to prepare the request for transmission?

A

HTTP, TCP, IP, Ethernet

Introduction to Networks (6 decks)

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