03_Protocols and Models

Question 1

The Rules

Answer 1

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.

Question 2

Protocols

Answer 2

• 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.

Question 3

Protocol Suites

Answer 3

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.

Question 4

Standards Organizations

Answer 4

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.

Question 5

Reference Models

Answer 5

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.

Question 6

Data Encapsulation

Answer 6

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

Question 7

Data Access

Answer 7

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.

Question 8

Message source (sender)

Answer 8

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

Question 9

Message Destination (receiver)

Answer 9

The destination receives the message and interprets it.

Question 10

Channel

Answer 10

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

Question 11

Common computer protocols include the following requirements:

Answer 11

• Message encoding
• Message formatting and encapsulation
• Message size
• Message timing
• Message delivery options

Question 12

Message encoding

Answer 12

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

Question 13

Message formatting and encapsulation

Answer 13

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.

Question 14

Message size

Answer 14

Another rule of communication is message size.

Question 15

Message timing

Answer 15

• 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.

Question 16

Message Delivery Options

Answer 16

• 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.

Question 17

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

Answer 17

encoding

Question 18

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

Answer 18

formatting

Question 19

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

Answer 19

• flow control
• access method
• response timeout

Question 20

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

Answer 20

multicast

Question 21

Network Communications Protocols

Answer 21

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.

Question 22

Network Security Protocols

Answer 22

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).

Question 23

Routing Protocols

Answer 23

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).

Question 24

Service Discovery Protocols

Answer 24

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.

Question 25

Computers and network devices use agreed-upon protocols to communicate

Answer 25

- Addressing - Reliability - Flow control - Sequencing - Error Detection - Application Interface

Question 26

Addressing

Answer 26

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.

Question 27

Reliability

Answer 27

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

Question 28

Flow control

Answer 28

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

Question 29

Sequencing

Answer 29

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.

Question 30

Error Detection

Answer 30

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

Question 31

Application Interface

Answer 31

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.

Question 32

Hyptertext Transfer Protocol (HTTP)

Answer 32

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.

Question 33

Transmission Control Protocol (TCP)

Answer 33

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

Question 34

Internet Protocol (IP)

Answer 34

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

Question 35

Ethernet

Answer 35

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

Question 36

BGP and OSPF are examples of which type of protocol?

Answer 36

routing

Question 37

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

Answer 37

- DNS | - DHCP

Question 38

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

Answer 38

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

Question 39

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

Answer 39

TCP

Question 40

Internet Protocol Suite or TCP/IP

Answer 40

This is the most common and relevant protocol suite used today

Question 41

Open Systems Interconnection (OSI) protocols

Answer 41

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

Question 42

AppleTalk

Answer 42

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

Question 43

Novell NetWare

Answer 43

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

Question 44

TCP/IP Protocol Example

Answer 44

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

Question 45

TCP/IP Protocol Suite

Answer 45

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

Question 46

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

Answer 46

- 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.

Question 47

Application Layer

Answer 47

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.

Question 48

Transport layer

Answer 48

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.

Question 49

Internet Layer

Answer 49

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.

Question 50

Network Access Layer

Answer 50

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.

Question 51

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

Answer 51

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

Question 52

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

Answer 52

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

Question 53

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

Answer 53

transport

Question 54

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

Answer 54

- DNS | - DHCP

Question 55

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

Answer 55

Ethernet

Question 56

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

Answer 56

- ICMPv4 | - ICMPv6

Question 57

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?

Answer 57

IP at the internet layer

Question 58

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

Answer 58

- Routing Protocols - Messaging - Internet Protocol

Question 59

Open Standards

Answer 59

Open standards encourage interoperability, competition, and innovation.

Question 60

Internet Society (ISOC)

Answer 60

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

Question 61

Internet Architecture Board (IAB)

Answer 61

Responsible for the overall management and development of internet standards

Question 62

Internet Engineering Task Force (IETF)

Answer 62

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

Question 63

Internet Corporation for Assigned Names and Numbers (ICANN)

Answer 63

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

Question 64

Internet Assigned Numbers Authority (IANA)

Answer 64

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

Question 65

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

Answer 65

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.

Question 66

Electronic Industries Alliance (EIA)

Answer 66

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

Question 67

Telecommunications Industry Association (TIA)

Answer 67

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.

Question 68

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

Answer 68

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).

Question 69

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

Answer 69

True

Question 70

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

Answer 70

Internet Engineering Task Force (IETF)

Question 71

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

Answer 71

Internet Assigned Numbers Authority (IANA)

Question 72

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

Answer 72

electric wiring and connectors

Question 73

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

Answer 73

- 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

Question 74

two layered models that are used to describe network operations

Answer 74

- 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

Question 75

OSI Reference Model

Answer 75

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)

Question 76

TCP/IP Protocol Model

Answer 76

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)

Question 77

segmenting messages having two primary benefits:

Answer 77

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.

Question 78

encapsulation process

Answer 78

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.

Question 79

De-encapsulation

Answer 79

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.

Question 80

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

Answer 80

segmentation

Question 81

What is the PDU associated with the transport layer?

Answer 81

segment

Question 82

Which protocol stack layer encapsulates data into frames?

Answer 82

data link

Question 83

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

Answer 83

encapsulation

Question 84

Network layer source and destination addresses

Answer 84

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.

Question 85

Data link layer source and destination addresses

Answer 85

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

Question 86

physical

Answer 86

timing and synchronization bits

Question 87

data link

Answer 87

destination and source physical addresses

Question 88

network

Answer 88

destination and source logical network addresses

Question 89

transport

Answer 89

destination and source process number (ports)

Question 90

upper layers

Answer 90

encoded application data

Question 91

Layer 3

Answer 91

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

Question 92

The IP packet contains two IP addresses

Answer 92

- 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.

Question 93

An IP address contains two parts

Answer 93

- 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.

Question 94

communicating with an FTP server on the same IP network

Answer 94

- 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.

Question 95

Role of the Data Link Layer Addresses: Same IP Network

Answer 95

- 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

Question 96

Role of the Network Layer Addresses

Answer 96

- 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.

Question 97

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

Answer 97

True

Question 98

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

Answer 98

False

Question 99

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

Answer 99

subnet mask

Question 100

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

Answer 100

- 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

Question 101

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

Answer 101

- destination MAC, source MAC

Question 102

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

Answer 102

False

Question 103

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

Answer 103

- IEEE - IETF - IANA

Question 104

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

Answer 104

broadcast

Question 105

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

Answer 105

to convert information to the appropriate form for transmission

Question 106

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

Answer 106

broadcast

Question 107

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

Answer 107

- 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

Question 108

What is the purpose of protocols in data communications?

Answer 108

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

Question 109

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

Answer 109

destination IP address

Question 110

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

Answer 110

protocol data unit

Question 111

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

Answer 111

- IP | - ICMP

Question 112

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

Answer 112

transport

Question 113

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

Answer 113

multicast

Question 114

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

Answer 114

decoding

Question 115

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

Answer 115

It is encapsulated in a Layer 2 frame

Question 116

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

Answer 116

encapsulation

Question 117

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?

Answer 117

HTTP, TCP, IP, Ethernet