https://medium.com/@cbarkinozer/temel-a%C4%9F-teknolojileri-850b48ff30d9
When it comes to establishing a connection between two computers, two techniques come to mind: Circuit Switching and Packet Switching techniques.
Circuit switching: The line mostly remains empty because transmission is made at regular intervals. For this reason, the cost is high. The circuit is established, data is transferred and the circuit is terminated. It is ideal for real-time applications such as audio and video. Data travels using the same path, so less processing is required at the destination to create the original message.
Packet Switching: Data packets are kept on the main lines during transmission, and transmission is carried out when the held packets reach sufficient capacity. Alternative routes can be used in transmission. The packets carry information about their arrival order.
Developed in the 1970s, ArpaNet is the ancestor of today's Internet.
Open architecture network: A network in which the choice of any network technology is not limited to a specific network architecture.
Network and Network components: "A network is when two or more electronic devices connect to each other wired or wirelessly and exchange data."
IP (internet protocol): It is one of the protocols that regulate communication between networks. Responsible for forwarding shipments from shipment to the recipient. The IP address is the unique address of the connection. IP is connectionless, best effort and media independent.
Time-to-live(TTL) (or hop limit): It is a mechanism that limits the lifespan of data on a computer or network. TTL can be implemented as a counter or timestamp added or embedded in the data.
Client: It is the structure that requests from the server to access the data in the system. It uses the data it receives from the server.
Server: It is a structure formed by clusters of high-performance computers that store the data in the system and deliver this data to the client when the request arrives.
Peer-to-peer network: It is a network protocol in which two or more computers are connected to each other to share data without the need for central control. It is called P2P or peer-to-peer. Computers communicate with each other using various protocols. It was easy to install. It is cheaper because network devices and dedicated servers are not required. It can be used for simple tasks like transferring files and sharing printers. There is no central management, it is insecure, it cannot be measured, and since all devices can be both clients and servers, performance may be negatively affected.
End devices: Devices such as tablets, phones, computers and printers where data is used.
Intermediary devices: These are devices that provide connections to end devices and work in the background to transfer data over the network. Bridge, gateway, hub, switch, and access point are media devices. They are used to create and send data signals. They provide information about routes on the network. They notify other devices of errors and communication issues. They classify and route messages according to quality of service (QoS) priorities. They allow or deny data flow depending on security settings.
Intermediary network devices: firewall, switch, router, and wireless access devices are examples. They work between the Network and Data link layers.
Router: They transfer IP packets from one device to another, using the network layer. A firewall is software that allows, records, blocks and alarms incoming packets within the rules given to it.
Network media selection criteria: The distance that the medium to be used can successfully carry a signal, the area where the medium to be used will be installed, the amount of data and transfer speed of the medium to be used, the medium to be used and the installation cost.
NIC/Network Interface Card:
Physical Port: It is a term used for connection points such as ports and sockets. It is an Ethernet card. It allows the end device to connect to the network.
Port types:
Serial port (RS232): Used very often. It is used in serial ports on computers.
Parallel port: It is faster than the serial port.
PS/2 ports: They were used for the keyboard and mouse (green colour for the mouse, purple colour for the keyboard). These devices now use USB port input.
SCSI port: Used to connect many devices consecutively.
Fireware: Much faster than a USB connection.
RJ-11 port: It is a telephone line port and is generally used for modem lines.
RJ-45 port: Ethernet port, used for network connection.
USB: Most devices today use this port.
Game port: Joystick, gamepad and game controllers are connected.
Sound card connection ports:
Audio Mini: Jack input.
Pink: For a microphone.
Blue: Stereo line-in input.
Green: Stereo lineout input.
Brown: For right-left audio systems.
Orange: For central audio systems.
VGA port: Both ends are designed for computer and monitor connection.
S-video port: Found on televisions and cameras, for video connection purposes.
DVI port (Digital Video Interface): p on LSD monitors is ordinal. It transfers the image from the graphics card with digital signals.
HDMI: It is a high-definition multimedia interface. Sound and image are transferred together.
e-SATA port: It is used as a communication accelerator between the hard disk and the computer.
Network interface: Usually an interface card, may also be software. The terms port and interface are interchangeable
Network diagrams: A way to make it easier to understand how devices in a large network are connected to the network. These diagrams are called topology diagrams. Visualizes the network structure. There are 2 types of topologies. Physical and logical topology. While the logical topology shows the addressing scheme of the devices and the network, the physical scheme shows the way cables connect the devices.
LAN: Local Network is the preferred connection method to establish a network connection between computers that are physically close to each other. There is no need for maintenance.
WAN (wide area network): It is the type of network that covers the largest geographical area. It refers to network structures spread around the world. He is slower than Wan Lan.
Internet: It is the electronic communication network that connects computer systems. It can also be defined as all interconnected computer networks.
MAN (metropolitan area network): It is a network that connects multiple LANs.
Intranet: Uses TCP/IP, it is the internal internet that uses a firewall. A company network can be given as an example.
Extranet: It is the communication network outside the company network. It is a private group and attention is paid to security. It is kept isolated from the intranet. Specially selected people and vehicles from the company can access it.
PAN (personal area network): It is a personal network formed by connecting personal devices to each other.
Protocols: A set of rules created by standard organizations.
Models: Provides a way to visualize rules and their place in your network.
Publication Types:
Unicast: Sent from one host to another.
Broadcast: Sent from a computer to all recipients.
Multicast: Sent from one computer to multiple participating computers. If you do not join the multicast broadcast group, you cannot receive multicast broadcasts.
Protocols: Common rules are required for devices to communicate. These rules are protocols and have many functions in a network.
Network communication protocols: Https, IPv6 and TCP/IP are examples.
Network security protocols: SSH, SSL, TLS/SSL are examples.
Routing protocols: OSPF and BGP are examples.
Service discovery protocols:
HTTP (hypertext transfer protocol): Provides the content and formatting of requests between client and server.
TCP: Responsible for the reliable transfer of information.
Ethernet: Responsible for message transmission between network interfaces in the same area network.
Layers: The transport layer carries segmentation (divided into segments), the network layer carries packets (segments are converted into packets by adding IP), the data link layer carries frames (a frame is created by adding the MAC address), the physical layer carries bits (frames are converted into bits).
MAC address: It is the unique address of the device. It is 48-bit.
DNS: Translates IP addresses into domain names. It operates on the OSI layer 7 application layer.
DHCPV6: After finding the IP address from the domain name, it is saved in memory and called from memory.
Email:
SMTP: It is a simple mail-sending protocol. It provides mail communication between servers and clients.
POP3: Allows users to receive email from the mail server and download the email to the local device.
IMAP: Protects emails on the server as well as allows clients to access emails on the email server.
File transfer:
FTP: It is a file transfer protocol. It enables the transfer of files from the mainframe to another computer via the server.
SFTP: It is an extension of SSH and encrypts file transfers.
TFTP: It is a junk file transfer protocol. It is disconnected.
Web:
HTTP: Provides image, document and audio communication on the Internet.
HTTPs: It is secure HTTP. Information is encrypted while being sent.
Transport layer protocols:
TCP: It is connection-oriented, and aims to send lossless data.
UDP: Uses less data bandwidth but does not care about data loss. Generally, videos and broadcasts use UDP.
Internet Layer:
Internet Protocol: IPv4 (packets messages and addresses), IPv6 (IPv4 using 128 bits), NAT (network address translation).
Messaging:ICMPv4(Internet control message protocol for IPv4),ICMPv6, ICMPv6 ND. Provides feedback on package deployment errors.
Routing Protocols:
OSPG: First open the shortcut. It is a link-state routing protocol that uses a domain-based hierarchical design.
BGP: It is an open standard external gateway routing protocol used between internet service providers.
EIGRP: It is an enhanced internal gateway routing protocol. It is an open standard routing protocol based on bandwidth, delay and reliability.
Network Access Layer: Address resolution ARP (provides dynamic address matching between IPv4 and MAC).
Data Link Protocols: Ethernet (cabling and standardization) and WLAN (wireless local area network).
OSI Layers: It divides packet exchange into layers, and each layer It also defines what needs to be done.
Application(provides communication between application processes)>Presentation(provides a common representation of transferred data)>Session(Manages session dialogue)>Transport(Transfers, moves and combines data between end devices)>Network(enables the exchange of data pieces)>Data Link( frames data over a common medium between devices)>Physical(manages physical connections).
Transport Layer: Uses TCP and UDP.
Session layer: NetBios, Remote procedure calls, named pipes and sockets operate in these layers.
Presentation Layer: Compression and analysis of data take place in this layer. GIF, Jpeg, and TIFF ASC work on these layers.
Ethernet Switching: Ethernet uses the data link layer protocols LLC and MAC sublayers to work.
Devices can send packets to 3 sources:
It can ping itself with the loopback address: 127.0.0.1.
To Local Host: To a device on the same network.
To Remote Host: This is the case when the target and the source device are on different networks.
ICMP(Internet Control Message protocols):
ICMPv4:
0: Network unreachable
1:host unreachable
2: protocol unreachable,
3: port not accessible.
ICMPv6:
0: no root target
1: admin is banned
2:Outside source address space
3:The address cannot be accessed
4: Port not accessible.
RTT (round trip time): The time it takes for a packet to reach the destination and be returned.
The "ipconfig -displaydns" command shows all cached DNS entries.
"Nslookup" is the terminal code to query the IP address from the domain.
SSH (Secure Shell): It is an access protocol used to remotely access and manage a network.
Reference:
BTK Academy-Basic Network Technologies Course
0 Comments