June Proverbs
In all things, we hope most beautiful; the most beautiful thing, never die. - Stephen King
third chapter
This chapter is mainly related to the transport layer
The intermediate transport layer is the application layer and the network layer, is responsible for sending data to the application layer of the network and receive data transferred to the corresponding application from the network layer .
The network layer provides a logical communication between hosts, and provides a logical communication between transport layers compared to processes running on different hosts.
Transport layer protocol running mainly TCP and UDP.
About UDP and TCP application layer has been simple to understand.
UDP：
UDP is connectionless (both transport layer before transmitting data without handshaking) unreliable transport protocol.
UDP transport protocol can only do a minimal amount of work to do, in addition to the multiplexer / demultiplexer and a small amount of error checking, UDP almost no IP add new features.
A UDP socket to fully identified by a tuple, the tuple is the destination IP address and destination port number.
Thus, if there are two UDP segments with two different source IP address and / or source port number, but with the same destination IP address and port number,
The two segments are directed to the same purpose socket process by the same purpose.
advantage:
What about when to send data and application layer transmission control is more subtle.
No need to establish a connection
No connection status
Packet header overhead small.
TCP：
TCP is connection-oriented, reliable transport protocol. A socket of a TCP four-tuple identified (the IP source, source port, destination IP, destination port number). Reaching two different TCP segment having a source IP address or port number will be directed to two different sockets.
Three-way handshake to establish a connection, four wave disconnect
TCP end to end congestion control must be used instead of using the secondary network congestion control, because the IP layer do not want to provide end system network congestion feedback display.
The method used is TCP allows each sender on the basis of perceived network congestion degree to which you want to connect to limit the rate of traffic transmitted.
TCP congestion control algorithms include: Slow Start / Congestion Avoidance / fast recovery wherein a slow start and congestion avoidance is a mandatory part of TCP's fast recovery section is recommended.
other:
Other transport layer protocol: Datagram Congestion Control Protocol (QCCP), QUIC (Quick UDP Internet Connections) protocol, DCTCP (Data Center TCP) protocol, Stream Control Transmission Protocol, TCP-friendly rate control protocol.
About transport layer This section also requires repeated several times to look at
Reproduced in: https: //www.cnblogs.com/lisaloveyou1900/p/11037122.html