Computer Networking Unit 1

host

(1) Any computer or device on a network that provides or uses a resource such as an application or data. (2) In the context of virtualization, the physical computer on which virtualization software operates and manages guests.

UDP (User Datagram Protocol)

- core protocol in the TCP/ IP suite that does not guarantee delivery because it does not first make the connection before sending data or check to confirm that data is received. -considered a connectionless protocol or best-effort protocol

router

-A Layer 3 device that uses logical addressing information to direct data between two or more networks and can help find the best path for traffic to get from one network to another. -a device that manages traffic between two or morenetworks and can help find the best path for traffic to get fromone network to another.•

IP (Internet Protocol)

-A core protocol in the TCP/IP suite that operates in the Network layer of the OSI model and provides information about how and where data should be delivered. IP is the subprotocol that enables TCP/IP to internetwork. -Adds its own Network layer header to the segment or datagram is now called a packet

WAN (Wide Area Network)

-A network that spans a long distance and connects two or more LANs. -example A corporation has an office in San Francisco and Philadelphia. Each office has its own LAN and a WAN link connects the two LANS, likely provided by a third-party service provider.

header

-An area at the beginning of a payload where protocols add control information. -added by each of the protocols to the beginning of the payload, called encapsulation

switch

-The determination of how connections are created between nodes on a network. -receives incoming data from one of its ports andredirects it to another port or multiple ports that will send thedata to its intended destination.

Data Link layer

-The second layer in the OSI model. The Data link layer also called the Link layer, bridges the Physical layer's networking media with Network layer processes. -Along with layer 1, responsible for interfacing with the physical hardware only on the local network -Examples include Ethernet and Wi-Fi

Application layer

-The seventh layer of the OSI model. Application layer protocols enable software programs to negotiate formatting, procedural, security, synchronization, and other requirements with the network. -Describes the interface between two applications from separate computers

segments

1) A TCP message at the Transport layer. (2) A part of a network.

fragmentation

A Network layer service that subdivides packets into smaller packets when those packets exceed the maximum size for the network.

datagram

A UDP message at the Transport layer.

client

A computer or application that makes a request from another computer or application.

SSH (Secure Shell)

A connection utility that provides authentication and encryption. SSH is often used to log onto a host, execute commands on that host, and copy files to or from the host.

TCP (Transmission Control Protocol)

A core protocol of the TCP/IP suite that makes a connection with the end host, checks whether data is received, and resends it if it is not.

-a combo device, which is both a router and a switch, and perhaps a wireless access point that creates a Wi-Fi hot spot. -Don't confuse this combo device with a dedicated router in which each port connects to a different LAN.

A home network might use

MAC (Media Access Control) address

A method of access control where resources are organized into hierarchical classifications, such as "confidential" or "top secret," and grouped into categories, perhaps by department. Users, then, are also classified and categorized. If a user's classification and category match those of a resource, then the user is given access.

OSI (Open Systems Interconnection)

A model for understanding, developing, and troubleshooting computer-to-computer communication and was developed in the 1980s by ISO. It divides networking functions among seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

SOHO (Small office/home office)

A network consisting of fewer than 10 workstations.

ring topology

A network layout in which each node is connected to the two nearest nodes so that the entire network forms a circle. Data is transmitted in one direction around the ring. Each node accepts and responds to packets addressed to it, then forwards the other packets to the next node in the ring.

LAN (local area network)

A network of computers and other devices that typically is confined to a relatively small space, such as one building or even one office. Each node on a LAN can communicate directly with others on the same LAN.

MAN (Metropolitan Area Network)

A network of connected LANs within a limited geographical area, such as multiple city government buildings around a city's center.

CAN (Campus Area Network)

A network of connected LANs within a limited geographical area, such as the buildings on a university campus.

PAN (Personal Area Network)

A network of personal devices, such as a cell phone, laptop, and Bluetooth printer.

port

A number that identifies a process, such as an application or service, running on a computer. TCP and UDP ports ensure that data is transmitted to the correct process among multiple processes running on a computer.

star topology

A physical topology in which every node on the network is connected through a central device.

SFTP (Secure File Transfer Protocol)

A protocol available with the proprietary version of SSH that securely copies files between hosts.

protocols

A standard method or format for communication between network devices.

TCP (Transmission Control Protocol)/ IP (Internet Protocol)

A suite of networking protocols that includes TCP, IP, UDP, and many others. TCP/IP provides the foundation for data exchange across the Internet.

connection-oriented protocol

A type of Transport layer protocol that requires the establishment of a connection between communicating nodes before it will transmit data.

mesh topology

A type of network in which several nodes are directly interconnected and no single node controls communications on the network.

IP address

A unique Network layer address assigned to each node on a TCP/IP network. IPv4 addresses consist of 32 bits divided into four octets, or bytes. IPv6 addresses are composed of eight 16-bit fields, for a total of 128 bits.

PDU (protocol data unit)

A unit of data at any layer of the OSI model.

-the centralized directory database that contains user account information and security for the entire group of computers -each user has his/her own domain level account assigned by the network administrator

Active Directory

SNMP (Simple Network Management Protocol)

An Application layer protocol in the TCP/IP suite used to monitor and manage devices on a network.

hub

An outdated connectivity device that belongs to the Physical layer of the OSI model and retransmits incoming data signals to its multiple ports.

node

Any computer or other device on a network that can be addressed on the local network.

-that provide services to the user (browser or web server) -that provide services to the system (SNMP)

Application layer protocols are used by programs that fall into what two categories?

remote access servers necessitate strict security measures

Because they can be accessed from outside the local network,

-a computer making a request from another -Can run applications installed on the desktop and store their own data on local storage devices

Client

-sometimes call the client-servor architecture or client-server topology -resources managed by the NOS Via a centralized directory database -can be managed by one or more servers, al long as they each have a similar NOS installed -examples are Windows Server 2016 or Ubuntu Server

Client-server network model

trailer

Control information attached to the end of a packet by a Data Link layer protocol.

payload

Data that is passed between applications or utility programs and the operating system, and includes control information.

-client-server application that transfers files between two computer -does not provide encryption, so not secure

FTP service

each computer shares files, folders, libraries, and printers with other computers in the homegroup

If all computers are running a windows operating system using a homegroup

each computer maintains a list of users and their rights on that particular computer

If all computers are running a windows operating system using windows folder and file sharing or using a workgroup

domain

In the context of Windows Server NOSes, a group of users, servers, and other resources that share account and security policies.

-require more memory, processing power, and storage capacity than clients in order to handle heavy processing loads and requests from multiple clients

NOS installed servers

-managing data and other resources for a number of clients -ensuring that only aurhorized users access the network -controlling which types of files a user can open and read -restricting when and from where users can access the network -dictating which rules computer will use to communicate -Supplying applications and data files to clients, in some situations

NOS is responsible for what?

the software that runs on a server and enables the server to mata, users, groups, security, applications, and other networking functions. Popular examples are Windows Server, Ubuntu Server, and Red Hat Enterprise Linux

Network Operating systems

-the resources a network makes available to its users include applications and the data provided by these application

Network services

a network in which every computer can communicate directly with every other computer. By default, no computer on a P2P network has more authority than another

P2P (peer-to-peer) network model

-POP3 email is downloaded to the server -IMAP4 client application manages the email while it's stored on the server

POP3 vs IMAP4

firmware

Programs embedded into hardware devices.

-methods and rules for communication -must first find the web server -the client and server must agree on the protocols used to communicate -the client makes the request and the server sends its response in the form of a web page

Protocols

-provides secure, encrypted transmissions that allow a technician to remote in -An Application layer protocol that uses TCP/IP to transmit graphics and text quickly over a remote client-host connection. RDP also carries session, licensing, and encryption information.

Remote desktop

used by the telnet client-server command-line application to allow an administrator or other user to "remote in" or control a computer remotely -A terminal emulation protocol used to log on to remote hosts using the TCP/IP protocol.

Telnet Service

AD DS (Active Directory Domain Services)

The Active Directory service that manages the process allowing a user to sign on to a network from any computer on the network and get access to the resources that Active Directory manages.

backbone

The central conduit of a network that connects network segments and significant shared devices (such as routers, switches, and servers) and is sometimes referred to as "a network of networks."

AD (Active Directory)

The centralized directory database that contains user account information and security for the entire group of computers on a network.

NIC (network interface card)

The device that enables a workstation to connect to the network and communicate with other computers. NICs are manufactured by several different companies and come with a variety of specifications that are tailored to the workstation's and the network's requirements. NICs are also called network adapters.

frame

The entire Data Link layer message, including the header, payload, and trailer.

packet

The entire Network layer message, which includes the segment (TCP) or datagram (UDP) from the Transport layer, plus the Network layer header.

Session layer

The fifth layer in the OSI model. The Session layer describes how data between applications is synced and recovered if messages don't arrive intact at the receiving application.

Transport layer

The fourth layer of the OSI model. The Transport layer is responsible for transporting Application layer payloads from one application to another.

Physical Layer

The lowest, or first, layer of the OSI model. The Physical layer is responsible only for sending bits via a wired or wireless transmission.

API (Application Programming Interface)

The process an application uses to make a request of the OS.

encapsulation

The process of adding a header to data inherited from the layer above.

Presentation layer

The sixth layer of the OSI model. Protocols in the Presentation layer are responsible for reformatting, compressing, and/or encrypting data in a way that the application on the receiving end can read.

Network layer

The third layer in the OSI model. The Network layer, sometimes called the Internet layer, is responsible for moving messages between networks.

-private or public -HTTP (Hypertext Transfer Protocol) -HTTPs (HTTP secure)

Web service can be?

-user accounts and passwords to the network are assigned in one place -access to multiple shared resources (such as data files or printers) can be centrally granted to a single user or groups of users -problems on the network can be monitored, diagnosed, and often fixed from one location -client-server networks are also more scalable than peer-to-peer networks -more secure -easiser to monitor and diagnose network issues and can be fixed from a remote location -more scalable

What are some advantages of a client-server network?

-web service -email services -FTP service -Telnet service -Remote applications -Remote desktop

What are some popular client-server applications?

-simple to configure and often less expensive -less expensive

What are the advantages of peer-to-peer

nodes or hosts on the network

What are the computers in a peer-to-peer system called?

more complex in design and maintenance

What are the disadvantages of a client-server network?

not scalable, not necessarily secure, and not practical for connecting more than a few computers because it is too time consuming to manage the resources on the network

What are the disadvantages of peer-to-peer

-MAC (Media Access Control) address -physical address -hardware address -Data Link layer address

What are the possible names for the hardware addresses contained in the frame header?

-Application -Presentation -Session -Transport -Network -Data Link -Physical

What are the seven layers of networking functions?

-TCP (guarantees delivery) -UDP (does not guarantee delivery)

What are the two main Transport layer protocols?

-Transmission Control Protocol (TCP) -Internet Protocol (IP)

What are the two primary protocols?

controlling how users and programs get access to resources on a network

What is a function of the operating systems used on a network?

controls network access to a group of computers

Windows domain (Windows Servers)

a switch belongs only to its local network and a router belongs to two or more local networks.

a The difference between a switch and a router is that

networking

a group of computer and other devices connected by some type of transmission media

server

any computer or program that provides a service, such as data or other resources, to other devices

network controllers or network interface controllers

both onboard and expansion network ports are sometimes called...

-data or a service requested by one cojmputer from another

client-server applications

topology

describes how the parts of a whole work together

LAN (Local Area Network)

each node on the network can communicate directly with others on the network; used in small spaces such as office buildings

-involves two servers -SMTP (Simple Mail Transfer Protocol) -used by the client to send an email message to the first server -first server sends the message to the receiver's mail server: where it is stored until the recipient requests delivery -POP3 (Post Office Protocol) -recipients mail server protocols that deliver the message to the receiving client

email services

peer to peer network model

in this each computer on a P2P network controls its own administration, resources and security -also the operating system of each computer is responsible for controlling access to its resources without centralized control -best for fewer than 15 computers

physical topology

mostly refers to a network's hardware and how computers, other devices, and cables fit together to form the physical network -the physical layout of the media, nodes, and devices on a network; does not specify device types, connectivity methods, or addressing schemes

an application that is installed and executed on a server and is presented to a user working at a client computer --A feature of Windows Server 2008 and later editions of Windows Server that allows technicians to manage remote applications.

remote applications

logical topology

software and how access to the network is controlled, including how users and programs gain access to the network and how specific resources, such as applications and databases are shared on the network -a characteristic of network transmission that reflects the way in which data is transmitted between nodes, including how access to the network is controlled and how specific resources are shared on the network. A network's logical topology may differ from its physical topology

hosts

the two end-system computers that initiate sending and receiving data

scalable

thee property of a network that allows an administrator to add nodes or increase its size easily

POP3 or IMAP4

used by the client to receive email

SMTP

used to send email to a recipients email server

requests a web page from a web server (server application);the web server returns the requested data to the client

web browser