Chapter 5 Flashcards by Frederick Karban

The process by which a connection-oriented protocol creates a connection. With TCP, a connection is established by a three-way transmission of TCP segments.

Connection-establishment

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The process of discovering whether a data link level frame was changed during transmission. This process uses a Frame Check Sequence (FCS) field in the data link trailer.

Error detection

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The process of noticing when some transmitted data was not successfully received and resending the data until it is successfully received.

Error recovery

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The process of regulating the amount of data sent by a sending computer toward a receiving computer.

Flow control

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A process used by protocols that do error recovery, in which the number that acknowledges data lists the next data that should be sent, not the last data that was successfully received.

Forward acknowledgement

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The protocol used by web browsers and web servers to transfer files, such as text and graphic files.

Hypertext transfer protocol (HTTP)

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A networking function, included in TCP, in which the protocol defines how the sending host should number the data transmitted, defines how the receiving device should attempt to reorder the data if it arrives out of order, and specifies to discard the data if it cannot be delivered in order.

Ordered data transfer

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In TCP and UDP, a number that is used to uniquely identify the application process that either sent or should receive data. In LAN switching, another term for switch interface.

Port

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In TCP, a term used to describe a TCP header and its encapsulated data (also called an L4PDU). Also in TCP, the process of accepting a large chunk of data from the application layer and breaking it into smaller pieces. In Ethernet, this is either a single Ethernet cable or a single collision domain (no matter how many cables are used).

Segment

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For protocols such as TCP that allow the receiving device to dictate the amount of data the sender can send before receiving an acknowledgment—a concept called a window—a reference to the fact that the mechanism to grant future windows is typically just a number that grows upward slowly after each acknowledgment, sliding upward.

Sliding windows

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The formal and correct term for the formatted text used to refer to objects in an IP network. This text is commonly called a URL or a web address. For example, http://www.certskills.com/blog is a URI that identifies the protocol (HTTP), hostname (www.certskills.com), and web page (blog).

Uniform Resource Identifier (URI)

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Software, running on a computer, that stores web pages and sends those web pages to web clients (web browsers) that request the web pages.

Web Server

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Which of the following header fields identify which TCP/IP application gets data received by the computer? (Choose two answers.)

a. Ethernet Type
b. SNAP Protocol Type
c. IP Protocol
d. TCP Port Number
e. UDP Port Number

d. TCP Port Number

e. UDP Port Number

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Which of the following are typical functions of TCP? (Choose four answers.)

a. Flow control (windowing)
b. Error recovery
c. Multiplexing using port numbers
d. Routing
e. Encryption
f. Ordered data transfer

a. Flow control (windowing)
b. Error recovery
c. Multiplexing using port numbers
f. Ordered data transfer

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Which of the following functions is performed by both TCP and UDP?

a. Windowing
b. Error recovery
c. Multiplexing using port numbers
d. Routing
e. Encryption
f. Ordered data transfer

c. Multiplexing using port numbers

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What do you call data that includes the Layer 4 protocol header, and data given to Layer 4 by the upper layers, not including any headers and trailers from Layers 1 to 3? (Choose two answers.)

a. L3PDU
b. Chunk
c. Segment
d. Packet
e. Frame
f. L4PDU

c. Segment

f. L4PDU

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In the URI http://www.certskills.com/ICND1, which part identifies the web server?

a. http
b. www.certskills.com
c. certskills.com
d. http://www.certskills.com
e. The file name.html includes the hostname.

b. www.certskills.com

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Fred opens a web browser and connects to the www.certskills.com website. Which of the following are typically true about what happens between Fred’s web browser and the web server? (Choose two answers.)

a. Messages flowing toward the server use UDP destination port 80.
b. Messages flowing from the server typically use RTP.
c. Messages flowing to the client typically use a source TCP port number of 80.
d. Messages flowing to the server typically use TCP.

c. Messages flowing to the client typically use a source TCP port number of 80.
d. Messages flowing to the server typically use TCP.

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Layer 4 defines several functions. What are the most important functions?

Error recovery and flow control

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What is the key difference between TCP and UDP?

TCP provides wide variety of services to application layer…UDP does not

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TCP provides retransmission (error _____) and helps to avoid congestion (flow control), whereas UDP does not.

recovery

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Between UDP and TCP, which one needs fewer bytes in the header, resulting in fewer bytes of overhead in the network?

UDP

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Voice over IP (VoIP) and video over IP, do not need error recovery, so they use _____.

UDP

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What is the function that allows receiving hosts to choose the correct application for which the data is destined, based on the port number?

Multiplexing using ports

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The process of numbering and acknowledging data with Sequence and Acknowledgement header fields?

Error recovery (reliability)

Process that uses window sizes to protect buffer space and routing devices from being overloaded with traffic

Flow control using windowing

Process used to initialize port numbers and Sequence and Acknowledgment fields.

Connection establishment and termination

Continuous stream of bytes from an upper-layer process that is "segmented" for transmission and delivered to upper-layer processes at the receiving device, with the bytes in the same order.

Ordered data transfer and data segmentation

Does UDP perform error recovery?

What RFC is TCP defined in?

RFC 793

What is the message created by TCP that begins with the TCP header, followed by any application data?

TCP segment

TCP and UDP _____ tells the receiving computer to which application to give the received data

multiplexing

Multiplexing relies on a concept called a _____.

socket

What three things does a socket consist of?

IP address Tranport protocol Port number

What well-known port number do web servers use by default?

Hosts typically allocate _____ port numbers starting at 1024 because the ports below 1024 are reserved for well-known applications.

dynamic

Well-known port numbers are used by _____; other port numbers are used by _____.

servers; | clients

Although it is often thought of as an end-user application, you can actually use WWW to manage a _____ or _____. You enable a web server function in either device and use a browser to access them.

router; | switch

What application layer protocol is specifically used for network device management?

Simple Network Management Protocol (SNMP)

Defines a protocol for basic file transfer.

Trivial File Transfer Protocol (TFTP)

Simple Mail Transfer Protocol (SMTP) and Post Office Protocol version 3 (POP3), both used for transferring mail, require guaranteed delivery. Which protocol would they use to guarantee delivery?

TCP

What port number and protocol does FTP data use?

20; | TCP

What port number and protocol does FTP control use?

21; | TCP

What port number and protocol does SSH use?

22; | TCP

What port number and protocol does Telnet use?

23; | TCP

What port number and protocol does SMTP use?

25; | TCP

What port number and protocol does DNS use?

53; TCP and UDP Note: Uses both TCP and UDP in different instances

What port number and protocol does DHCP server use?

67; | UDP

What port number and protocol does DHCP client use?

68; | UDP

What port number and protocol does TFTP use?

69; | UDP

What port number and protocol does HTTP use?

80; | TCP

What port number and protocol does POP3 use?

110; | TCP

What port number and protocol does SNMP use?

161; | UDP

What port number and protocol does SSL use?

443; | TCP

What port number and protocol does Syslog use?

514; | UDP

The process of initializing Sequence and Acknowledgment fields and agreeing on the port numbers used. It occurs before any other TCP features can begin their work.

Connection establishment

The connection establishment flow is a ____-way connection, which must be established before data transfer can begin.

three

What are the only parts of a socket that need to be encoded in the TCP header?

port numbers

TCP signals connection establishment using 2 bits inside the flag fields of the TCP header. What are these flags called?

SYN and ACK

What does SYN stand for?

synchronize the sequence numbers

The TCP connection termination is a four-way termination sequence, using an additional flag, called the _____ bit.

FIN

What does FIN stand for?

Finished

_____ establishes and terminates connections between the endpoints, whereas UDP does not.

TCP; | UDP

A protocol that requires an exchange of messages before data transfer begins, or that has a required pre-established correlation between two endpoints.

Connection-oriented protocol

A protocol that does not require an exchange of messages and that does not require a pre-established correlation between two endpoints.

Connectionless protocol

To accomplish reliability, TCP numbers data bytes using the _____ and _____ fields in the TCP header

Sequence | Acknowledgement

TCP achieves _____ in both directions

reliability

The acknowledgement by listing the next expected byte, rather than the number of the last byte received, is called _____ acknowledgment.

forward

The _____ concept lets the receiving host tell the sender how much data it can receive right now, giving the receiving host a way to make the sending host slow down or speed up.

window

What is the term used when the receiver can slide the window size up and down, which changes how much data the sending host can send?

sliding window or dynamic window

_____ is connectionless and provides no reliability, no windowing, no reordering of the received data, and no segmentation of large chunks of data into the right size for transmission.

UDP

DNS requests use _____ because the user will retry an operation if the DNS resolution fails

UDP

UDP has only _____ bytes, in comparison to the 20-byte TCP header.

The _____consists of all the Internet-connected web servers in the world, plus all Internet-connected hosts with web browsers.

WWW (World Wide Web)

Web browsers are also called web _____, because they obtain a service from a web server.

clients

These clickable items on a web page, which in turn bring you to another web page

links

The browser user can identify a web page when you click something on a web page or when you enter a _____ in the browser’s address area.

URI (Uniform Resource Identifier)

HTTP defines several commands and responses, with the most frequently used being the HTTP _____ request.

GET

If the server decides to send the file, the server sends an HTTP GET response, with a return code of _____ (meaning OK), along with the file’s contents.

200

Many return codes exist for HTTP requests. For example, when the server does not have the requested file, it issues a return code of _____, which means “file not found.”

404

Web pages typically consist of multiple files, called _____

objects

What hex value does an IPv4 header have?

0800

The IPv4 Protocol field has a standard list of values that identify the next header, with decimal __ used for TCP and decimal __ used for UDP.

6; | 17

Chapter 5 Flashcards

(83 cards)