NT1 Midterms

standards

documented agreements containing technical specifications or other precise criteria that stipulate how a particular product or service should be designed or performed

• institute of electrical and electronics engineers (IEEE)

• american national standards institute (ANSI)

• electronic industries alliance (EIA)

• telecommunications industry association (TIA)

• internet engineering task force (IETF)

• organization for standardization (ISO)

these are the common standardization organizations

institute of electrical and electronics engineers (IEEE)

• international society composed of engineering professionals

• aims to promote development and education in the electrical engineering and computer science fields

standardization of LAN technologies

what is IEEE probably best known for?

IEEE’s Project 802

this project aided in the standardization of ethernet (802.3), token ring (802.5). and wireless LANs (802.11)

american national standards institute (ANSI)

an organization composed of more than one thousand representatives from industry and government who determine standards for electronics, industry and other fields such as chemical and nuclear engineering, health and safety,

• american standard for code information interchange (ASCII)

• small computer system interface (SCSI)

ANSI is known for published standards such as these two:

electronics industries alliance (EIA)

• trade organization composed of representatives from electronics manufacturing firms across the US

• writes ANSI standards and legislation favorable to the growth of computer and electronic industries

telecommunications industry association (TIA)

focuses on standards for information technology, wireless, satellite, fiber optics, and telephone equipment

TIA-EIA 568 - B Series

the best known standards to come from the TIA/EIA alliance are its guidelines for how network cable should be installed in commercial buildings, known as ___

internet engineering task force (IETF)

• organization responsible for the overall development of the internet and the standardization of internetworking technologies

• sets standards for how systems communicate over the internet

• internet society (ISOC)

• internet engineering steering group (IESG)

• internet architecture board (IAB)

• internet assigned numbers authority (IANA)

these are the four groups under the IETF

internet society (ISOC)

oversees the overall development on the internet

internet engineering steering group (IESG)

oversees activities of IETF and manages the process used to introduce or update internet standards

internet architecture board (IAB)

serves as the technology advisory group to the internet society and is responsible for all overall development of the protocols and architecture associated with the internet

internet assigned numbers authority (IANA)

• oversees internet naming and addressing

• in charge of all unique parameters on the internet

organization for standardization (ISO)

an international standards organization responsible for a wide range of standards, including many that are relevant to networking

application layer

this provides interfaces for application software so that applications can use network services. its protocol designates transport layer protocols and ports

• simple mail transfer protocol (SMTP)

• post office protocol, version 3 (POP3)

• trivial file transfer protocol (TFTP)

• file transfer protocol (FTP)

• network file system (NFS)

• domain name system (DNS)

• simple network management protocol (SNMP)

• terminal emulation protocol network (Telnet)

• remote login application (rlogin)

• hypertext transfer protocol (HTTP)

• HTTPS (Hypertext Transfer Protocol over Secure Socket Layer)

these are the application layer proto

simple mail transfer protocol (SMTP)

refers to a TCP/IP protocol that specifies a reliable and efficient transfer of electronic mail service on the internet

post office protocol, version 3 (POP#)

refers to a TCP/IP protocol that is designated to allow a workstation to retrieve mail that the server is holding for it

trivial file transfer protocol (TFTP)

a small and simple alternative to FTP that uses UDP to transfer files between systems

file transfer protocol (FTP)

• refers to a TCP/IP protocol that enables the sharing of computer programs and data between hosts over a TCP/IP network

• uses TCP to create virtual connection for control information and creates separate TCP connection for data transfer

network file system (NFS)

refers to a TCP/IP protocol that enables computers to mount drives on remote hosts and operate them as if they were local drives

domain name system (DNS)

refers to a TCP/IP protocol that is used on the internet for translating names of domains and their publicly advertised network nodes into IP addresses

simple network management protocol (SNMP)

• refers to a TCP/IP protocol that monitors and controls the exchange of management information between networks and network components

• enables network admins to manage configs, stats collection, network

• managed devices

• agent

• NMS

SNMP model includes these three components:

managed devices

these collect and store management information and make this information available to NMS using SNMP

agent

has local knowledge of management i

NMS

• executes applications that monitor and control managed devices

• provides the bulk of the processing and memory resources required for network management

terminal emulation protocol network (Telnet)

refers to a TCP/IP protocol that uses the TCP as the transport protocol to establish a connection between server and client

daemon

telnet uses a special software called ___, which is referred to as a remote host

virtual terminal (VTY) session, or connection

a connection using telnet is called a ___

remote login application (rlogin)

is a UNIX command that allows authorized users to log in to other UNIZ machines (hosts) on a network and to interact as if the user were physically at the host computer

hypertext transfer protocol (HTTP)

an application level protocol service and an internet standard developed by the IETF that supports the exchange of information on the world wide web, as well as on internal networks

HTTPS (hypertext transfer protocol over secure socket layer)

a secure message-oriented communications protocol designed for use in conjunction with HTTP

Secure Sockets Layer (SSL)

• security protocol that works at a socket level

• exists between the TCP layer and the application layer to encrypt/decode data and authenticate concerned entities.

• Transmission Control Protocol (TCP)

• User Datagram Protocol (UDP)

Computers running on the Internet communicate to each other using either these two

Transport Control Protocol (TCP)

refers to a connection-oriented TCP/IP standard transport layer protocol that provides reliable data delivery, duplicate data suppression, congestion control, and flow control on which many application protocols depend.

true

(T/F) Transport protocols are used to deliver information from one port to another and thereby enable communication between application programs.

true

(T/F) The reliability of the communication between the source and destination programs is ensured through error-detection and error-correction mechanisms that are implemented within TCP.

User Datagram Protocol (UDP)

refers to a connectionless TCP/IP standard transport layer protocol that provides unreliable, best-effort service.

datagrams

UDP is a protocol that sends independent packets of data, called ___, from one computer to another with no guarantees about arrival

true

(T/F) Sending datagrams is much like sending a letter through the postal service: The order of delivery is not important and is not guaranteed, and each message is independent of any other

true

(T/F) under port numbers, data transmitted over the internet is accompanied by addressing information that identifies the computer and the port for which it is destined

32-bit IP address

the computer is identified by its ___, which uses IP to deliver data to the specific computer on the network

ports

these are identified by a 16-bit number, which TCP and UDP use to deliver the data to the specific application

0 to 65,535

port numbers range from ___ because ports are represented by 16-bit numbers

well-known ports

port numbers ranging from 0 - 1023 are restricted; they are reserved for use by well-known services such as HTTP and FTP and other system services called ___

• source port

• destination port

• sequence number

• acknowledgment number

• header length

• reserved

• control bits

• window

• checksum

these are the 9 TCP header fields

Source Port

• identifies the application that sends the segment

• 16 bits long.

Destination Port

• identifies the application that receives the segment

• 16 bits long

Sequence Number

• refers to every byte of data sent over a TCP connection

• value of this field is equal to the sequence number of the first byte in a sent segment.

• 32 bits long

Acknowledgment Number

• indicates sequence number of the next segment's first byte that the receiver is expecting to receive

• value of this field is 1 plus the sequence number of the last byte in the previous segment that is successfully received.

• This field is 32 bits long.

Header Length

• indicates the length of the TCP header.unit is 32 bits (4 bytes). If there is no option content, the value of this field is 5, indicating that the header contains 20 bytes.

Reserved

• this field is always set to 0 as it is intended for future protocol changes. It is 6 bits long.

Control Bits

include FIN, ACK, and SYN flags which indicate the TCP data segments in different states

Window

• is used for TCP flow control.

• The value is the maximum number of bytes that are allowed by the receiver

Checksum

is a mandatory field in which it is calculated and stored by the sender and verified by the receiver.

• source port

• destination port

• length

• checksum

these are the 4 UDP header fields

Source Port

• identifies the application that sends the segment.

• This field is 16 bits long.

Destination Port

• identifies the application that receives the segment.

• This field is 16 bits long

Length

• specifies the total length of the UDP header and data.

• The possible minimum length is 8 bytes because the UDP header already occupies 8 bytes

Checksum

• refers to the checksum of the UDP header and UDP data.

• This field is 16 bits long.

Three-way handshake

is a method in which the sender and the receiver inform their respective operating systems that a connection will be initiated before the actual data communication begins.

synchronize

SYN means?

acknowledge

AC means?

finish

FIN means?

Sequence Number and Acknowledgment Number

fields to implement reliable and ordered data transmission.

Window Sliding Mechanism

requires the sender to receive an acknowledgment from the receiver after transmitting a certain amount of data.

TCP Shutdown (Four Way Handshake)

is engaged when the data transmission is complete in order to disconnect the TCP connection and release system resources.

• IP version 4 (IPv4)

• IP version 6 (IPv6)

currently, these are the two versions of an IP

1981

when was IPv4 deployed?

1992

when was IPv6 deployed?

32-bit (4 bytes) addressing scheme

what is the address size of IPv4?

128-bit (16 bytes) addressing scheme

what is the address size of IPv6?

dotted decimal notation

what is the address format of IPv4?

hexadecimal notation

what is the address format of IPv6^?

192.149.0.0/24

what is the prefix notation of IPv4?

3FEE:F200:0234:AB00:0123:4567:8901:ABCD

what is the prefix notation of IPv6?

2³²

what is the number of addresses of IPv4?

2¹²⁸

what is the number of addresses in IPv6?

media access control (MAC) address

refers to the unique physical addresses of all computers, which are assigned by the manufacturer of the network interface card

organizational unique identifier (OUI)

• the first 24 bits of the MAC address that is vendor specific

• identifies the company that manufactured or sold the device (eg network interface card, router ports)

vendor-assigned

• the remaining 24 bits of the MAC address that is incrementally and uniquely assigned by the specific vendor of the hardware

• denotes the serial number of the individual device

IP address

refers to an address that is usually assigned by the network administrator or internet service provider to uniquely and universally identify each device on an IP network

public IP address

• is what computers use to find each other online and exchange information

• is assigned to the computer by the ISP as soon as the computer is connected to the internet gateway

static public IP address

a fixed IP address and is used primarily for hosting web pages otr services on the internet

dynamic public IP address

is chosen from a pool of available addresses and changes each time one connects to the internet

private IP address

• is what computers on a network use to communicate with the router

• can change each time they are connected

• network ID/field

• host ID

these are the two parts of an IP address

network ID/field

part of an IP address that identifies the host that is located on the same physical network

host ID

• also known as host address

• identifies the individual host within a network

class A address

• uses only the first octet (8 bits) of the 32-bit number to indicate the network address

• entire second to fourth octet is used for host addresses, now equivalent to a total of 24 bits

class B address

• uses two of the four octets (16 bits) to indicate the network address

• the two other octets, which specify the host addresses, now have a total of 16 bits

class C address

• uses the first three octets (24 bits) of the IP address to identify the network portion, with the remaining octet reserved for the host portion, which is equivalent to eight bits

class D address

an address created to enable multicasting using an IP address

multicast address

is a unique address that directs packets with that destination address to predefined groups of hosts

class E address

this is reserved by the internet engineering task force (IETF) for its own research

1.0.0.0 to 127.0.0.0

Network,Host,Host,Host

24 no. of bits used

16,777,214 maximum host

this represents the class A address