chptr13 Flashcards

1
Q

NIC Network Interface Controller

A

serves as the hardware interface between computer and network

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2
Q

End to end channel

A

nic to cloud/sps to nic

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3
Q

Open Systems Interconnection Reference Model OSI

A

theoretical model as a standard by ISO - used for research

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4
Q

TCP/IP

A

integrated suite consisting of numerous protocols that control aspects of data communication - 5 layers: Application - Transport - Network - Data Link - Physical

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5
Q

Protocol Stack

A

each layer of the stack at the sending node contributes information that will be used by the corresponding peer layer

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6
Q

Program Applications

A

Safari - Outlook - Skype etc

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7
Q

Network Applications

A

designed to present the message to the network in a format that can be understood by each of the hardware and software components of the channel - standard protocols part of TCP/IP

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8
Q

Application Layer

A

contains the program and network applications

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9
Q

Ethernet

A

comprises layers 1 and 2 of the tcp/ip protocol suite - Physical and data link layers

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10
Q

frame

A

bits of an Ethernet packet sent through a single link from one node to another in a LAN

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11
Q

non-Ethernet packets

A

also called frames at the data link layer

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12
Q

not a node

A

hub switch or Wi-Fi access point are transparent to data being moved

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13
Q

Physical Layer

A

Level 1 - layer at which the communication actually takes place. Includes medium - signaling method - specific signal parameters - voltages - carrier frequencies - lengths of pulses etc. Sync and timing issues

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14
Q

Data Link layer

A

Level 2 - responsible for transmission and delivery of packets across the communication link between nodes. Two sublayers Medium Access Control MAC and
Logical Link Control LLC

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15
Q

collision

A

two messages collide

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16
Q

Carrier Sense Multiple Access with Collision Detection CSMA/CD protocol

A

Ethernet - connections are point to point and collisions are not possible.

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17
Q

MAC Address

A

Address for each node on the Ethernet network - permanently assigned by the IEEE org to manufacturers of Ethernet attached equipment. NIC

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18
Q

Network Propagation delay

A

the amount of time it takes for a packet to get from one end of the network to the other

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19
Q

WI Fi ad hoc mode

A

assumes direct connections between Wi-Fi nodes and is based on a partial mesh network topology. Depends on a network of available coop stations rarely is used

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20
Q

Wi Fi infrastructure mode

A

variation of CSMA/CD is used for infrastructure Wi-Fi. Collision handling is required. Delays due to collisions are much longer than those on a wired hub

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21
Q

Carrier Sense Multiple Access with Collision Avoidance CSMA/CA protocol

A

a station listens until channel clear to transmit. Then transmits frame to access point. When frame reaches its destination the receiver checks for errors then sends a short acknowledgment packet to indicate receipt

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22
Q

Logical Link Control (within Datalink)

A

resize frame if necessary optional error checking - frame numbering or reordering/recombining frames

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23
Q

Media Access Control (within Datalink)

A

add frame header. Encode bytes of frames to bits in format and signal type appropriate for medium and signal method of physical layer. On receiving message it decodes bit stream to bytes of frame and removes frame header.

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24
Q

The Network Layer

A

Layer 3 - responsible for addressing and routing of packets from the source end node through intermediate nodes - step by step - to their proper final destination.

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25
Q

TCP IP Network layer

A

aka internetworking layer or IP layer

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26
Q

IP datagrams

A

IP level packets within a LAN

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27
Q

Layer 3 switches

A

routing takes place at the network layer - routers and gateways are sometimes called this

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28
Q

fragments

A

ip datagram fragments are reassembled by IP when the final destination is reached using header info that is stored with each fragment. IPv6 rejects fragments instead

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29
Q

ICMP Internet Control Message Protocol

A

auxiliary protocol that creates error messages that occur when there is a failure in procedures

30
Q

Transport Layer

A

Layer 4 - purpose is to take messages from the network applications and provide services that support reliable end to end communications. Responsible for generating the final address of the destination. Responsible for packetization of the message. implemented with 3 different protocols: TCP; USER Datagram Protocol UDP; and Stream Control Transmission Prot SCTP

31
Q

Port addresses or numbers

A

16 bits - first 1024 numbers are “well known ports”. Ie port 80

32
Q

socket

A

operating systems provide an interface called a socket for comms between apps and trans layer

33
Q

TCP - Transmission Control Protocol

A

connection-oriented service. Before any data packets are sent to receiving node TCP at the sending node establishes a connections with TCP at the receiving node. Sends message. Closes the connection. Reliable delivery service

34
Q

Logical Connection

A

operates independently of the actual physical characteristics of the network (TCP connector) - separate from the message route

35
Q

Segments

A

TCP packets are called this by some network practitioners - since data content is part of an ordered sequence of bytes

36
Q

handshaking

A

the brief initial connections made by TCP with a random 32 bit number to number the packets

37
Q

UDP User Datagram Protocol

A

used for some applications instead of TCP. Connectionless service. No comms between sender and receiver prior to sending message. Datagram is sent independently. Faster and simpler but no guarantee on delivery. Streaming video is an example

38
Q

User datagrams

A

UDP packets are known as this. Contains the message exactly as delivered from the application. App has to divide message into smaller pieces.

39
Q

SCTP - Stream Control Transmission Protocol

A

offers features similar to TCP with improvements to fault tolerance and enables multiple messages in byte streams to be transported simultaneously through same connections. Will allow redirect to other ip address if failure in first address.

40
Q

DNS - Domain Named System/Server

A

Translates domain names into ip addresses

41
Q

IP addresses

A

standards for location resources on the internet.

42
Q

ICANN

A

registers domain names and ip addresses

43
Q

Static IP Addresses

A

permanently assigned to computers etc

44
Q

Dynamic Addresses

A

assigned on an as needed basis using DHCP

45
Q

DHCP - Dynamic Host Configuration Protocol

A

Within the application layer - assigns and reclaims IP addresses from a pool of addresses. DHCP client resides on the computer or device being connected which connects to the DHCP server

46
Q

DDNS Dynamic Domain Name Service

A

Can provide a link by updating the local DNS server so that a computer with a dynamic address can be open to public.

47
Q

IPv6

A

Created since IPv4 addresses are gone. 128 bits long; 256 trillion trillion trillion different ip addresses. Sequence of 8 4 digit hexadecimal numbers

48
Q

Colon-hexadecimal notation

A

IPv6 address written in this: 2fc3:4ab2:4470:0001:FFDC:BB54:c126:7001

49
Q

DNS Root Server

A

Top of the root directory - 13 servers all over. Handle 50 billion queries a day

50
Q

Top-Level Domains

A

.com; .edu; .org; .net; .de; .cn; .uk

51
Q

country-code top-level domain servers (ccTLDs)

A

Country identifiers .de; .cn etc

52
Q

generic top-level domain name servers (gTLDs)

A

.com; .edu; .org etc.

53
Q

Second-level or third-level domain names

A

Registered through ICANN - ie amazon.com etc.

54
Q

replication

A

process used to synchronize the multiple dns servers

55
Q

resolution

A

translation process when converting a web address to IP address

56
Q

local DNS server

A

not part of the dns hierarchy - could be on host machine - on the LAN or isps site

57
Q

jitter

A

defined as the variation in delay from packet to packet

58
Q

QoS Quality of Service

A

focuses on 2 params: methods to reserve and prioritize channel capacity to favor packets that require special treatment. Service guarantees from contracted carrier services that specify particular throughput - delay and jitter

59
Q

Differentiated Service DS field

A

8 bit field - index into a table that defines various classes of service. Routers can prioritize and route packets based on packet class

60
Q

Network Security

A

1-5 categories: Intrusion; Confidentiality; Authentication; Data integrity and nonrepudiation; assuring network availability and access control

61
Q

NS Intrusion

A

Keeping systems and network intact and free from intrusion

62
Q

NS Confidentiality

A

Keeping content of traveling data private

63
Q

NS Authentication

A

Verifying identity of source of data being received. Similar to electronic signatures.

64
Q

NS Data integrity and nonrepudiation

A

Protecting data against changes and verifying the source of a message.

65
Q

NS Assuring network availability and access control

A

Restricting access to authorized users; keeping network up and running to those users

66
Q

Packet Sniffing

A

reading of data in a packet as it passes

67
Q

Physical Access Restriction

A

limiting access to network wiring and equipment to personnel.

68
Q

Logical Access Restriction

A

Limited with intelligent firewall design that blocks public access where it is not required.

69
Q

Encryption

A

provides security beyond other measures.

70
Q

Symmetric key cryptography

A

requires that the same key be used for both encryption and decryption

71
Q

Public key-private key cryptography

A

two different keys - one public other private are used together in various ways to achieve the different goals.

72
Q

Network Address Translation NAT

A

Use of private ip addresses behind a router; router must readdress traffic passing between the internet and local network; difficult with large networks; software that is intelligent