TCP/IP principle-Internet Protocol

IP: The task is to transfer data based solely on the address of the source host and destination host. For this purpose, IP defines the encapsulation structure of the addressing method and datagram.

Characteristics:

A. Unreliable. It does not guarantee that IP datagrams will successfully reach their destination. IP only provides the best transport service. If some kind of error occurs, such as a router temporarily ran out of buffers, I p has a simple error

Processing algorithm: Discards the datagram, then sends the I C M P message to the source end. The reliability of any requirement must be provided by the upper layer (e.g. T C P).

B. No connection. No connection (c o n n e c t i o n l e s s) This term means that I p does not maintain any status information about subsequent datagrams.

The processing of each datagram is independent of each other.

IP datagram:

1. High on the left, low on the right. 4-byte 32-bit transmission order in the network: First, 0~7bit, followed by 8~15,16~23,24~31.

This order is called big-endian, and becomes the network byte order.

2. The header Length field. The header length refers to the number of 32-bit words, including any option * (may or may not be available). Because it is 4 bits, the first maximum is (8+4+2+1) *4=60 bytes.

The 3.tos:4 bit's to s represent: minimum delay, maximum throughput, maximum reliability, and
Small fee. Only 1 of these bits can be placed in a 4 bit.

4. The total length field refers to the entire length of the IP datagram, in bytes. Data length = total length-ip of the First Minister.

5. The identity field uniquely identifies each datagram sent by the host. It usually adds 1 to the value of each message sent.

6.TTL (time–to-live): Sets the maximum number of route hops the datagram can have been.

7. Protocol: According to it can identify which protocol is transmitting data to I p.

8. The first Test and field is the test and code calculated according to the first

IP Routing options:

TCP/IP principle-Internet Protocol