215 Midterm Review
In the physical layer there are:
frames, switches, data links
Internet
interconnection of networks with different network access, has own set of machines and routers
What command provides a list of running processes on our computer?
ps
Header Checksum Field
16 bits. Sender calculates a number based on other bits and places number in the field.
Hosts on the internet have ___ addresses.
2
Trailers are found in which layer?
2, ethernet frames, datalink
What is (are) the well-known port number(s) for FTP? -20 and 21 -25 -80
20 and 21
An 8-bit field can represent ________ alternatives.
256
In the network world the message syntax is composed of ______ parts by default?
3
How long are IPv4 addresses?
32 bits, 4 octet
320,000,000 bps is
320 Mbps
On an Ethernet network, your network address will be your
48 bit MAC address
Ethernet addresses are ________.
48 bits long
MAC Addresses are ______________octets (bytes).
6
If two hosts are separated by seven networks, how many frames will there be along the way when a host transmits a packet to another host?
7
At which layer would you find file transfer protocol (FTP) standards for downloading files?
Application
For human reading, IPv4 addresses usually are expressed in ________. A) hexadecimal notation B) dotted decimal notation C) Both A and B
B
The Internet Protocol is responsible for placing in order packets that arrive out of order. T or F
False
You would use TCP at the transport layer if you did not need error correction or could not use error correction. T or F
False
Client PC's provide service to other client PC's in _____ applications
P2P
______________ data sent in discrete "chunks" (packets); each has a path chosen for it. -circuit switching -packet switching
Packet Switching
Why use UDP?
Packets it as soon as the applicate process writes into the socket. NO DELAY (doesn't have 3 way hand shake)
Which layer process does NOT do encapsulation when an application layer process transmits a message?
Physical
A computer connects to the nearest switch via a
Physical Link
When a switch receives a packet, the switch selects the ________.
Port to send the packet out
A network interface mode that allows you to see every single packet that has been transmitted or received on the interface. -wireshark
Promiscuous mode
The first directory in the file system in Linux
Root directory
What segments only have headers?
SYN and TCP
Host P transmits a SYN to Host Q. If host Q is willing to open the connection, it will transmit a/an ________ segment -Ack -SYN -SYN, ACK
SYN, ACK
The meaning of a message is referred to as the message's ________.
Semantics
[me@linuxbox ~]$ - includes username@machinename -current working directory -$
Shell Prompt-
A program that takes keyboard commands and passes them to the operating system to carry out
Shell or command line
Fragmentation is done on which host?
Source Host
TCP/IP includes UDP. T or F
True
The creation of internetworking required the introduction of 2 addresses for each host. T or F
True
The creation of internetworking required the introduction of two addresses for each host. T or F
True
Using reserved capacity, the data transmission speed for a voice conversation remains constant regardless of how many people are using the system at the same time. T or F
True
How many data links will there be if a frame passes from a computer through two switches, then through a router, then through two more switches, and then to the destination computer -6 -1 -2 -8
Two
What is the command for deleting a user account?
Type in sudo su and user del
connectionless, data messaging service -should be used only when data is not essential (ex: audio/video streaming)
UDP protocol
Types of Ethernet Cables
10BaseT & 100Base T (physical layer)
In binary, the decimal 13 is equivalent to 1101. What is 14?
1110
broadband connection
Analog signaling (more precise)
47,000,000 bps is -47 kbps -47tbps -47 mbps -47 gbps
-47mbps
When a packet passes through seven switches between the source and destination hosts (no routers), the number of physical links is ______, while the number of data links is ____. -1,8 -14, 1 -1, 7 -8,1
-8, 1
IP version 6 addresses are ________. -32 bits long -64 bits long -128 bits long
128 bits long
Which of the following uses packet switching? -dial-up telephone circuits -neither dial up telephone circuits nor leased line circuits -both -leased line circuits
-neither dial up telephone circuits nor leased line circuits
Breaking down a message into many packets is done on the _______ while the reassembly of packets into a message is done on the _______. -both source host and destination host -source host; destination host -destination host, source house
-source host; destination host
A typical packet is about ____ long.
100 bytes
The first 128 characters of the ASCII standard are encoded into binary using ______ bits, however, when any of these characters are stored in a computing environment such as a Host, it's stored as______ bits. Hint: number. -8,8 -8,7 -7,8 -7,7
7,8
What is the well-known port number for HTTP?
80
What layer number is the physical layer? A) 1 B) 2 C) 3 D) None of the above
A
Which of the following is written in dotted decimal notation? A) IPv4 addresses. B) IPv6 addresses. C) Both A and B D) Neither A nor B
A
Data field contains
A TCP segment and UDP datagram.
Ethernet Frame
A term referring to an Ethernet data link header and trailer, plus the data encapsulated between the header and trailer.
IP Packet
AlWAYS has a header and data field. NEVER has a trailer.
commands that we can define ourselves, built from other commands
An alias
What layer number is the data link layer? A) 1 B) 2 C) 3 D) None of the above
B
Which of the following gives you the IP address of a host you wish to communicate with? A) DHCP. B) DNS. C) Both A and B D) Neither A nor B
B
Which of the following is a networked application? A) The Internet. B) The World Wide Web. C) Both A and B D) Neither A nor B
B
Which of the following layers governs transmission across an Internet? A) Layer 2. B) Layer 4. C) Both A and B D) Neither A nor B
B) Transport Layer
Digital signaling that has only one signal (a single signal) on the cable at a time.
Baseband.
Why are there some frames labeled as HTTP under the protocol header after applying the TCP filter?
Because some TCP frames contain HTTP request and response messages.
Which of the following has greater resistance to transmission errors? -Binary Signaling -Analog Signaling
Binary signaling
What are field lengths measured in?
Bits or Bytes "octet"
Transport port fields are found in ? -UDP headers -TCP headers -Both -Neither
Both
"Octet" is another name for
Byte
A device attached to a network is called a ________. A) client B) server C) host D) Either A or B
C
If you did not need error correction or could not use error correction at the transport layer, you would choose ________. A) IP B) TCP C) UDP D) None of the above
C
What layer number is the internet layer? A) 1 B) 2 C) 3 D) None of the above
C
Which of the following is a networked application? A) E-mail. B) The World Wide Web. C) Both A and B D) Neither A nor B
C
Ethernet's MAC policy
CS=carrier sense --> only send data if the medium is idle MA=multiple access--> all can access and send messages CD= collision damage
In P2P applications, most processing is done on the ________. -client -server
Client
Routers used to be called ________. A) IMPs B) switches C) Network Access Points D) gateways
D
What layer number is the transport layer? A) 1 B) 2 C) 3 D) None of the above
D
Which of the following is a host when it is on a network? A) A client PC. B) A server. C) A mobile phone. D) All of the above
D
Which of the following is not a function of a wireless access router? A) Ethernet switch. B) DHCP server. C) Network address translation (NAT). D) DNS server.
D
Applications that use UDP
DNS, multimedia streaming, phone calls, gaming
Contains the packet that the frame is being delivered
Data field
A ________ is the path that a packet takes across a single switched network and its src and dst physical addresses stay unchanged. -transport -physical link -connection -data link -route
Data link
Reassembly is done on which host? -destination -source -both -neither
Destination Host
Routers make packet forwarding decisions based on a packet's _____.
Destination IP address
Command that asks for an IP address for a website
Dig (space) website
A modem converts original ________ signals to ________ signals that can be transmitted through the telephone system.
Digital, Analog
________ is placing a message in the data field of another message. -encapsulation -nesting -encoding -layering
Encapsulation
B7-22-DD-6F-C8-AB is a/an ________ address. -ethernet -IP -TCP
Ethernet
How we connect to a network. Standard defines datalink layer and physical layer connectivity.
Ethernet
Only the __________ has a trailer as a part of the message.
Ethernet Frame
Everything is connected through a switch. Hubs are connected by twisted pair facilitate this topology.
Ethernet Topology: Star
Ethernet Topology: Mesh
Every host is reachable though at least one connection
Broadcast
Everyone in network gets it; all 1s
Ethernet Topology: Star
Everything is connected through a switch. Hubs are connected by twisted pair facilitate this topology.
Ethernet Frames contain error correction and are reliable. T or F
F
The side wishing to close a TCP segment sends a(n) ________ segment. -ACK -SYN -FIN
FIN
A route is the path a frame takes across a single network, from the source host to the destination host, across multiple switches. T or F
False
A switch knows a packet's entire path through a switched network T or F
False
Any home TV must be a " Network Host" ? T or F
False
Ethernet detects errors but does not correct them. Therefore, Ethernet is reliable. T or F
False
Frames are carried inside packets. T or F
False
In terminal-host processing, processing is done on both the terminal and the server. T or F
False
Messages (segments, packets or frames) always have data fields. T or F
False
Spelling internet with a lowercase i indicates you are talking about the global internet. T or F
False
Multicast
First bit is 1; only goes to 1
TCP Close a Connection
Four messages close the connection. --> FYN
Dividing a message into a series of smaller messages is called ____.
Fragmentation
The trailer of an ethernet frame contains what?
Frame Check Sequence (error detection)
Clone that is a complete copy of the VM and is fully independent.
Full clone
Used to facilitate shared connections
Hubs
Which network standard deals with addresses and functionality for routers to move packets across an Internet? -IP -TCP -UDP
IP
Which network standard governs the hop-by-hop (a hop is host to router or router to router) transmission of packets across an internet? -IP -TCP -UDP
IP
Which standard deals with addresses and functionality for routers to move packets across an internet?
IP
What command displaces information about all network interfaces currently in operation?
Ifconfig
Provides unreliable, unordered, connectionless service.
Internet Protocol
Which type of circuit typically operates at faster speeds?
Leased circuit lines
Clone that uses a reference to the original VM, requires less disk space, and cannot run without access to the original
Linked Clone
First thing received on receiver end. Data field contains the content being delivered. Header is everything before data field.
Message Syntax
connectionless protocol
No connection required between sender and receiver. Can easily lose packets. Useful for periodic burst transfers.
Which of the following places a heavier burden on the internet? -TCP -Ip -UDP
TCP
Which standard corrects errors?
TCP
Which standard does fragmentation?
TCP
Which standard places packets that arrive out of order in order? -IP -TCP -UDP
TCP
always have headers, some don't have data fields, never trailers
TCP Segment
connection oriented, stream of bytes service, reliable, flow/congestion control.
TCP protocol
When your PC requests an IP address from a DNS (Domain Name System), the DNS responds with a message containing the IP address of __________.
The host your trying to reach
What does it mean if the last character of the prompt is a # sign?
The terminal session has superuser privileges.
error detection, doesn't correct, can only discard frame
Trailer
Ethernet Frame contains
Trailer, Header, and data field
Which layer governs the transmission of packets across an internet?
Transport Layer, Network Layer
Which layer governs end-to-end transmission between two hosts across an internet?
Transport layer
A network is a system that permits networked applications on different hosts to work together. T or F
True
A smart phone connected to an internet is a host. T or F
True
All binary signaling is digital signaling. T or F
True
Each layer provides services to the layer above it. T or F
True
Headers usually are divided into fields. T or F
True
In cloud computing, server management is outsourced. T or F
True
In general, same local network address equals the same data link. T or F
True
Multiplexing reduces transmission cost. T or F
True
command to copy files and directories
cp
Packets are carried inside frames. T or F
True
Circuits are reasonably efficient for ________ transmission.
Voice
Inside a computer, data is represented as -decimal -hexadecimal -binary
binary
Network speeds usually are measured in ________.
bits per second
In client/server processing, processing is done on the ________. -neither client nor server -both client and server -server -client
both client and server
command- change directory
cd
Frequency division multiplexing (FDM) is an example of sharing bandwidth under ______________________.
circuit switching
An internet
connection of networks interconnected by layer 3 switches/routes
Requires a session connection be established before any data can be sent. "reliable." and guarantees that data will arrive in the same order
connection-oriented protocol
Which of the following have explicit openings and closings? -connectionless protocols -connection-oriented protocols -both -neither
connection-oriented protocols
After the internet "Network" layer process does encapsulation, it passes the IP packet to the ________ layer process. -physical -transport -data link -application
data link
What command creates a textile?
edit
Converting application messages (consist of characters) into bits is called ________. -encapsulation -encryption -encoding -conversion
encoding
Programs that can be compiled binaries. ex python
executable program
command- list directory contents
ls
For bursty data, packet switching is desirable because it ________. -makes transmission more efficient -reduces transmission time -both -neither
makes transmission more efficient
command that displays a programs manual prage
man
command to create directories
mkdir
The _______ is often drawn as a cloud to emphasize that the user does not need to know what is going on internally.
network core
If the destination host receives a segment that is incorrect, it will ________. -transmit an ACK segment -transmit a NAC segment -transmit an RSND segment -none of these
none of these
command that displays the DNS and ip address
ns lookup
If two hosts are separated by seven networks, how many packets will there be along the way when a host transmits a packet to another host?
one
After the side wishing to close a TCP connection sends a FIN message, it will ________. -not send any more segments -only send ACK segments -only send FIN segments
only send ACK segments
In the network layer there are
packets, routers, routes
In internets, different networks are connected by
routers
An HTTP message is encapsulated at the transport layer to become a TCP ___________ , which in turn is encapsulated at the internet layer to become an IP ________ , which in turn it's encapsulated at the data link layer to become an Ethernet _________ .
segment, packet, frame
How a message is organized is its ________. -syntax -semantics -order
syntax
The header of an ethernet frame contains what?
the MAC address
In TCP, which process decides whether to retransmit a lost or damaged segment—the original sender or the receiver?
the original sender
UDP checks messages for errors but does not correct them. UDP is ________. -reliable -unreliable -connection-oriented
unreliable
