Comparison of IP,UDP,TCP,SCTP characteristics

Summary of IP,UDP,TCP,SCTP finishing

1. protocol stack:

Application Layer	DNS, HTTP, FTP, TELNET, SSH, SIP, H.248/mgaco, diameter, MGCP, M3ua,m2ua,m2pa,sua ...
Transport Layer	Udp	Tcp	Sctp
Network layer	IP (ARP/RARP)
Data Link Layer	Network device drivers

2. IP layer Features: No connection, unreliable, disorderly;

· Mainly responsible for routing, split/and IP datagram, data distribution (distributed according to Protocol and port number to transport layer protocol);

· unreliable : The IP layer receives the data sent from the transport layer to pack and send immediately, will not keep the backup in the cache, because the IP layer is not responsible for retransmission; The IP layer at the end does not know whether the IP datagram sent is correctly received on the end;

· There are two main cases of IP datagram loss: one is the transmission of the entire datagram lost; the second is that the packet was fragmented, the end timer after timeout did not receive all the fragments, can not spell the original end of the data, so can only have received fragments also discarded; If the upper level has a demand for reliability, it needs to be guaranteed by the transport layer;

· disorder , refers to the IP layer received to the end of the IP datagram will be sent to the transport layer, does not care about sending to the order of the end, if the upper level of the order required to be guaranteed by the transport layer;

3. UDP Features: No connection, unreliable, disordered, based on application layer message;

· Because the IP layer itself is not connected, unreliable, disorderly, and UDP did not do special processing, so UDP is still connectionless, unreliable, disorderly; about "application-layer message" means that the application layer calls the interface that sends the message (SENDTO) to send a piece of data, UDP does not do any processing to the data, Just add the UDP head and then give it to the IP layer, so if the application layer sends a larger chunk of data each time, it can easily cause IP layer fragmentation;

· In addition, UDP also has the following characteristics:

1 The local and remote IP address can be restricted;

2) Support broadcast and multicast;

· The following is the head structure of UDP:

MAC Header

IP Header

UDP Header

Data:::

UDP Header:

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