当前位置：网站首页>IP lesson summary (3)

IP lesson summary (3)

2022-07-24 06:16:00 【Nine character Chen】

Catalog

Network type ---- Divide according to the protocol used in the data link layer

MA--- Multipoint access network

P2P--- Take you to point network

Data link layer protocol

PPP--- Point to point agreement

characteristic ：

PPP The agreement has a series of membership agreements

PPP Data transmission process ：

3、 ... and 、

Network type ---- Divide according to the protocol used in the data link layer

MA--- Multipoint access network

BMA--- Broadcast multipoint borrowing is like network

NBMA--- Non broadcast multipoint access network

P2P--- Take you to point network

Data link layer protocol

1. Ethernet protocol ： Need to use MAC Address distinguishes and identifies different host devices --- Why Ethernet needs to be used MAC Address for data addressing , This is mainly because the layer-2 network using Ethernet components can contain multiple （ Two or more ） The interface of , Each Ethernet interface can carry out layer-2 communication by means of interactive Ethernet frames . －－－ BMA

1-2. When a network can only contain two devices , Then such a network does not need to be used MAC Address address , Such a network is called P2P The Internet .

T1 －－－ 1.544Mbps

E1 －－－ 2.048Mbps

1-3. Ethernet -- Frequency division technology --- So called frequency division , Send my radio waves of different frequency bands at the same time in the same transmission medium , And they don't interfere with each other , Realize the parallel transmission of data

2.HDLC--- String agreement ( Advanced data link control protocol )

2-1 The standard HDLC:ISO Those that meet industrial standards issued by the organization HDLC edition

2-2 Nonstandard HDLC: Major manufacturers based on Standards HDLC The agreement has been improved

（ By default , The serial network of Cisco device components uses the encapsulation protocol HDLC, Huawei uses PPP agreement .)

PPP--- Point to point agreement

characteristic ：

1 Strong compatibility , There is a unified version , And as long as it supports full duplex serial lines ,

You can use PPP Protocol encapsulation .

2 With strong portability

3 Support authentication and authorization

PPP The agreement has a series of membership agreements

－－－ LCP －－ Link control protocol （ One ）

－－－ NCP －－ Network control protocol （ a pile ）

－－－ IPCP agreement

F --- Flag －－－ 01111110

A －－－ Address －－－ 11111111 C －－－ control －－－ 00000011

agreement －－－ Indicates the protocol type used by the upper layer .

FCS --- Frame check sequence －－－ Ensure data integrity

PPP Data transmission process ：

PPP The protocol and TCP The agreement is similar to , Before transmitting data , Need to establish PPP Conversation .

1, Link establishment phase －－－ LCP establish

2, Authentication phase －－－ optional

3, Network layer protocol negotiation stage

－－－ NCP negotiation －－－ NCP An agreement is a collection of agreements .

－－－ IPCP agreement

1. Link establishment phase －－－ LCP establish MRU --- PPP The maximum number of bytes allowed to be carried in the data part of the frame . －－－ 1500 Whether authentication is required in the second stage of byte and the authentication method

2, Authentication phase －－－ optional －－－－ PPP Usually by calling aaa Platform to complete the certification process .

PPP Both one-way authentication and two-way authentication are supported in

PAP----- Password authentication protocol －－－ The authenticated party sends the user name and password in clear text

To the certifier , If the authentication is successful , Then the certifier replies ACK; Otherwise reply NAK.

CHAP －－－ Challenge the handshake agreement －－－ safer , No longer send plaintext directly for authentication , Instead, authentication is performed by comparing the summary values .

HASH（ Hash function ）－－－ Convert input of any length into output of fixed length .

1, Same input , Same output ;

2, Irreversibility

3, Avalanche effect

MDS --- HASH One of the algorithms , Input of any length can be converted into 128 The output of a

3, Network layer protocol negotiation stage －－－ NCP negotiation －－－ If the third floor uses IP agreement , You need to use IPCP Protocol to negotiate its parameters

1,IP Compression format of message ;2,IP Address