<인터넷의 원리>
data center --------------------> device (mobile phone / laptop)
1. browser sends a request to the DNS server to get the corresponding IP address
IP address
: Every device connected to the internet (ex. server. computer. mobile phone. etc) is identified uniquely by an IP address (string of numbers)
- IP address of servers: Domain names are used
DNS server
: provides IP address corresponding to the domain name you are finding
2. browser gets IP address
3. browser forwards the request to the respective data center
4. server gets a request to access a particular website
5. data flow starts
6. data is transferred in digital format via optical fiber cables
7. Optical fiber cables are stretched to doorstep connected to a router
Device should be connected to the internet via cellular data / Wi-Fi router
8. Router converts light signals to electrical signals
9. Ethernet cable transmits the electrical signals to the device
Protocol
: management of data packets flow
- set the rule for data packet conversion & attachment of the source and destination addresses to each packet & routers
- TCP/IP: transports data
- http/https: web access
- RTP: live video streaming, VoIP calls
<Ethernet>
1. Physical layer (OSI 1)
1) Cabling
fiber optic cable, twisted pair cable
half-duplex, full-duplex
Ethernet to fiber converter
2) Devices
any device having either an internal or external NIC
Switch, Router
: director of network, connect computers or networks
Gateway, Bridge
: connect Ethernet networks
2. Data link layer (OSI 2)
1) LLC (Logical Link Control)
makes paths for data on the Ethernet to transmit b/w devices
2) MAC (Media Access Control)
uses hardware addresses assigned to NIC to show the source and destination of data transmissions
Ethernet transmits data packets in data link layer by using CSMA/CD(-> reduce data collision, increase successful data transmission)