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Hcip - HDLC and PPP protocols

2022-07-23 12:49:00 【Newcomer_ L】

OSI Seven layer reference model protocol model corresponding to each layer

1、 The physical layer The agreement has ：EIA/TIA-232,du EIA/TIA-499,V.35, V.24,RJ45, Ethernet, 802.3

2、 Data link layer The agreement has ：Frame Relay,HDLC,PPP, IEEE 802.3/802.2

3、 The network layer The agreement has ：IP,IPX,AppleTalk DDP,ARP

4、 Transport layer The agreement has ：TCP,UDP,SPX

5、 The session layer The agreement has ：RPC,SQL,NFS,NetBIOS,names,AppleTalk

6、 The presentation layer The agreement has ：TIFF,GIF,JPEG,PICT,ASCII,EBCDIC,encryption

7、 application layer The agreement has ：FTP,WWW,Telnet,NFS,SMTP,Gateway,SNMP,Dns

Network type according to Data link layer The use of agreement Divided

MA--- Multipoint access network

BMA--- Broadcast multipoint access network

NBMA--- Non broadcast access network

P2P--- Point to point network

Ethernet protocol --- Need to use MAC Address For different host devices distinguish and identification .--- Why Ethernet needs to be used MAC address Data addressing , Mainly because of the use of Ethernet components Layer 2 network Can contain Multiple （ Two or more ） The interface of , Each Ethernet interface can be connected through Interaction Ethernet frame Layer 2 communication . --- BMA

P2P The Internet --- When a network It can only contain two Equipment time , Such a network No need to use MAC Address Conduct Addressing , Such networks are called P2P The Internet .

T1 --- 1.544Mbps

T2 --- 2.048Mbps

Ethernet --- Frequency division --- So called frequency division , Is in the The same transmission medium On can meanwhile send out Radio waves of different frequency bands , And they don't interfere with each other . Realize the parallel transmission of data .

1、HDLC

HDLC --- Advanced data link control protocol

The standard HDLC: from ISO Those that meet industrial standards issued by the organization HDLC edition

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

（ By default , Cisco device components The encapsulation protocol used in the serial network is HDLC, Huawei The default is PPP agreement ）

[r1]display interface Serial 4/0/0--- Check the interface Of Second level features

[r1-Serial4/0/0]link-protocol hdlc --- Modify the second floor Of Protocol type

2、PPP

PPP--- Point to point agreement

1、 Strong compatibility , There is a unified version , And as long as it is Support full duplex String line of , You can use PPP Agreement to proceed Subpackage .

2、PPP The agreement has a strong Portability . ---PPPoE（ For dial-up Internet access ）

PPPOE:

PPPoE（Point-to-Point Protocol over Ethernet） It can be called the Ethernet PPP agreement , Apply to The link layer . It passes over the Ethernet Provide point-to-point connections , establish PPP conversation , encapsulation PPP message by PPPoE message .PPPoE Technology can connect users to remote access devices , And provide good Access control function , It provides an economical user access technology , And realize the control of users .
PPPoE It has the following characteristics ：

The function ：

PPPoE Because of the integration PPP agreement , It realizes what traditional Ethernet cannot provide Authentication 、 Encryption and compression .

PPPoE Through the only Session ID It can be very good Ensure the safety of users .

On the application ：

PPPoE Dial up networking is the most common way for terminal devices to connect ISP So as to achieve broadband access .

PPPoE Can be used for Cable modem （Cable Modem） and Digital subscriber line （DSL） Wait for the Ethernet cable , Via Ethernet A protocol system that provides access services to users .

3、 Support authentication and authorization （ It is convenient to realize the billing system ）

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

1、 Link establishment phase --- LCP establish

2、 Authentication phase --- optional

Network layer protocol negotiation stage --- NCP negotiation --- NCP An agreement is a collection of agreements --- IPCP agreement

PPP The agreement has a series of membership agreements --- LCP -- Link control protocol （ One ）-- NCP -- Network control protocol （ a pile ）---IPCP agreement

F---Flag --- 7E( Change to binary to 01111110)

A---Address --- FF（ Fixed for 11111111）

C---control---03（ Fixed for 00000011）

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

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

1、 Link establishment phase --- LCP establish

MRU --- PPP frame The data part of is allowed to carry Maximum number of bytes . --- 1500 byte

Whether certification is required in the second stage and the certification method

2、 Authentication phase --- optional

--- PPP Usually by call aaa Platform Complete certification Process of .

--- PPP It supports One way Authentication , Also support Multiple certifications

PAP--- Password authentication protocol --- The authenticated party will send the user name and password With Plaintext Send to the authenticator in the form of , If certified success , Then the certifier replies ACK; Otherwise reply NCK.

CHAP --- Challenge the handshake agreement --- safer , No longer send plaintext directly for authentication , It is By comparing the summary value The way to authenticate .

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

1、 Same input , Same output ;

2、 Irreversibility ;

3、 Avalanche effect ;

MD5 --- HASH One of the algorithms , Can be Input of any length is converted into 128 The output of a

3、 Network layer protocol negotiation stage --- NCP negotiation --- If Three layers It uses IP agreement , You need to use IPCP Protocol to negotiate its parameters

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