Linux High Performance Programming learning Notes (1)

TCP/TP Protocol Family: Layered, multi-protocol communication system, four-layer protocol system, bottom-up: Data link layer, network layer, Transport layer, application layer
Data Link Layer: A network driver that implements the interface of the NIC to handle the data being transmitted on the physical medium
Data link Layer Two common protocols: ARP Protocol (Address Resolution Protocol), RARP protocol (Inverse Address Resolution Protocol)
Network Layer: Implement Routing and forwarding of packets
The most core protocol of the network layer is the IP Protocol (Internet Protocol), and the other important protocol is the ICMP protocol (Internet Control Message Protocol).
Transport Layer: Provides end-to-end communication for applications on two hosts
There are three main transport layer protocols: TCP Protocol (Transmission Control Protocol) (providing reliable, connection-oriented and stream-based services to the application layer)
UDP protocol (User Datagram Protocol) (in contrast to the TCP protocol, provides unreliable, non-connected, datagram-based services for the application tier)
SCTP protocol (Flow Control Transfer Protocol) (designed to transmit phone numbers over the internet)
Application Layer: The logic responsible for processing the application
Application layer protocol: Ping is an application, not a protocol
Telnet protocol is a remote login protocol
OSPF (Open Shortest Path First) protocol is a dynamic routing update protocol
DNS (Domain Name Service) protocol provides conversion of machine domain name to IP address

The upper layer protocol implements a call to the downlevel protocol through encapsulation
TCP encapsulated data is called a TCP packet segment (or TCP segment)
UDP-encapsulated data is called a UDP datagram
The data after the TP encapsulation is called the IP datagram
Data that is encapsulated by the data link layer is called a frame

ARP Protocol (Address Resolution Protocol): the ability to implement any network layer address to any physical address conversion
Use the ARP command under Linux to view and modify the ARP tell cache
For example: sudo arp-d 192.168.1.109 #删除
sudo arp-s 192.168.1.109 08:00:27:53:10:67 #添加

Observing the ARP communication process using tcpdump

DNS (Domain Name Service) Protocol : DNS is a set of distributed domain Name Service systems. A large number of mappings for machine names and IP addresses are stored on each DNS server, and are dynamically updated
Tcpdump with "IP address." Port number "to describe one end of the communication:" > "means the direction of the data transmission," > "Front is the source, followed by the destination end

Linux High Performance Programming learning Notes (1)