Tcp/ip five layer reference model and corresponding typical devices and IPv6

Environmental Science ：ENSP Software     Huawei ;s5700  s3700  AR2220 etc.   Specific instructions will be sorted out later   Mainly based on this sharing theory

One . Network transmission distance

• Wide area network （Wide-Area Network） Range : Tens to thousands of kilometers effect : Used to connect remote computer networks Typical applications :Internet（ Internet ）

• LAN （Local-Area Network） Range :1 Km or so effect : Used to connect computers in a short distance Typical applications : Enterprise network , Campus network

      The physical layer ： Device hardware network card chip   for example ：intel or Realtek Lineage

Two . Data link layer

        There are two main functions ： Frame coding and error correction control ; Two-layer switch .

• The address of the network ip Address ： Need to customize when using Use decimal 0~9 192.168.0.1
• mac Address ( Physical address or hardware address )： No need to customize , When the equipment leaves the factory, it will carry Use hexadecimal 0~F 0123456789ABCDEF 52:54:00:37:78:11 // It is usually used to identify the uniqueness of the equipment , Do not modify the , The global only

1.  How switches work Study Learn the source in the data frame mac Address 3 radio broadcast Send target seeking information to all interfaces other than the data source forward One to one transfer of data to update When the number of devices connected to the switch exceeds 300 No data transfer in seconds And disconnect the device from the switch , Will cause the switch to clear the corresponding Mac The action of address

display mac-address // see mac Address

2.  How switches work ：

• Study ： Learn the source in the data frame mac Address    
• radio broadcast ： Send target seeking information to all interfaces other than the data source
• forward One to one transfer of data    
• to update ： When the number of devices connected to the switch exceeds 300 No data transfer in seconds And disconnect the device from the switch , Will cause the switch to clear the corresponding Mac The action of address

3.  VLAN：

Broadcast area ： Broadcast domain refers to the collection of nodes that receive the same broadcast message , For example, the same office in the actual environment Same classroom , Can be understood as the same broadcast domain    

 VLAN ：Virtual LAN（ Virtual LAN ） use VLAN All interfaces of the switch belong to the same broadcast domain by default With the increase of access devices , More broadcasts on the Internet , Reduce the efficiency of the network In order to split the broadcast domain , Introduced VLAN vlan The advantages of        1, Broadcast control 2, Increase security 3, Improve bandwidth utilization 4, Reduce data delivery latency

• Trunk access Access link Can carry 1 individual vlan The data of ;
• trunk Relay link Can carry more than one vlan The data of ;
• Link aggregation , Multiple links can be used ( network card ) Tied together , Achieve increased reliability , Improve The purpose of link bandwidth .

Example ：############

3、 ... and , The network layer

1. The network layer In the data link layer, it can be implemented through the switch vlan Divide 、 Relay link 、 Link aggregation Configuration of , Meet the basic needs of building a network , However, this layer cannot transmit data further , Like different vlan The data cannot be exchanged , So to make the data transfer farther , Need to make
2. Use the functions of the network layer The network layer can realize the following functions ： Defined ip Address You can connect different media types ( Networks of different ranges 、 Different hardware 、 Different systems ) You can choose the best path for data to pass through the network ( Automatic route selection when the network structure is complex )

Three layer switch : Powerful network equipment with switch and router functions at the same time Three layer switch = Router ( Three layers )+ Switch ( On the second floor )  

Interface configuration of layer 3 switch ip Ideas ：

1. Create a vlan
2. Access to the vlan Virtual interface configuration ip
3. You will need to configure ip Add the above interface vlan

• A gateway is a way for a device to go to another network , Usually by the router ( With routing Functional devices ) To undertake
• Routers rely on routing tables to forward data Generation method of routing table ：

1. Direct link routing , Configure the interface ip And it will automatically generate ;
2. Static routing , It is manually configured by the administrator , Add the required route Grammar format ：ip route-static Target segment Mask Next jump ;
3. Dynamic routing , Based on some kind of routing protocol , Suitable for large networks , Reduce administrative tasks Declare Inform the outside world of the network segment you are directly connected to ;  “ Write whatever network segment you have ”##

   [Huawei]ospf

   [Huawei-ospf-1]area 0

   [Huawei-ospf-1-area-0.0.0.0]network 192.168.4.0 0.0.0.255   // Declare 4 Network segment

   [Huawei-ospf-1-area-0.0.0.0]network 192.168.5.0 0.0.0.255   // Declare 5 Network segment

4. Default route , It's a special static route , Can match any network segment Specifically used to access massive external networks .

      notes ： The router can be configured on the physical interface ip, The layer-3 switch should enter the virtual interface configuration

vrrp  Virtual routing redundancy protocol

vrrp It can be used without changing the networking , Virtual multiple routers into a virtual router , By configuring the IP The address is the default gateway , Backup the gateway .

1. VRRP Group member role
2.                             Lord (Master） Router
3.                             Backup （Backup） Router
4.                             fictitious （Virtual） Router
5. 

Four . Transport layer

•                     Defines the port number   65536 individual   0~65535 

1.                     Defined tcp、udp Two agreements

tcp Transmission control protocol

reliable    Low efficiency    Connection oriented

Use tcp Some marks are used when transmitting data ：

syn Intend to establish a connection with each other

ack confirm

fin  Intend to disconnect from each other

Three handshakes

1. user syn---> The server

2 . The server ack , syn ---> user

3.  user ack---> The server

Four disconnects

1, user fin---> The server

2, The server ack ---> user

3, The server fin ---> user

4, user ack---> The server

#### Use tcp Common services for protocol data transmission

  

####udp User datagram protocol

unreliable    Efficient    There is no connection

Use udp Common services for transmitting data

• acl Access control list

A tool that can control the established network

basic acl  List number 2000~2999  According to the data source ip Address control

senior acl  List number 3000~3999  According to the data source ip、 The goal is ip、 Protocol port for control

####nat Network address translation

Private address can be converted into the world's only public address

Wide area network   Extranet

LAN   Intranet

ip Address  32 position   Have 42 Billion + And has dried up

private ip Address

A 10.0.0.0~10.255.255.255

B 172.16.0.0~172.31.255.255

C 192.168.0.0~192.168.255.255

nat Two common uses ：

1.                             Static conversion  1 Yes 1  Two-way communication
2.                             easy ip    How to 1  One-way communication
3. 
4. 

ipv6:

• ipv4  32 position   42 Billion +   dotted decimal
• ipv6  128 position   Near infinite address space   It's hexadecimal
• 2001:0002:0003:0004:0005:0006:0007:0008 /64  // One
• ipv6 Address , from 8 paragraph 4 Hexadecimal composition of bits , Follow up 64 Represents prefix length