Hcip first day notes sorting

HCIA---- Huawei junior network engineer certification

HCIP---- Senior Network Engineer under Huawei certification system

Abstract language --- code

code --- Binary system

Binary system --- Electrical signals

Process electrical signals

agreement , standard , application , service

OSI（ Open system interconnection ） Reference model ---OSI/RM---ISO---1979 year

application layer --- Provide various application services , Convert abstract language into code , Provide an interface for others to interact

The presentation layer --- Convert the encoding to binary

The session layer --- Maintain session links between web applications and web servers

Transport layer --- Realize end-to-end communication --- Port number ---0 - 65535--- among 0 It is not used as the port number of the transport layer , therefore , The real value range of the port number is 1 - 65535--- among 1 - 1023 It's called a well-known port number ---SPORT,DPORT

The network layer --- Use IP Address realizes logical addressing between hosts ---SIP,DIP

obtain DIP Address method ：

1. Know the server directly IP Address

2. Access the server through the domain name

3. Access the server through the application

4. radio broadcast

Data link layer --- Control physical hardware , Convert binary to electrical signal --- In Ethernet , The data link layer needs to pass MAC Address for physical addressing ---48 Bit binary structure ---1、 The only global ;2、 use the same pattern ---SMAC,DMAC

obtain DMAC Methods ---ARP agreement --- Address resolution protocol

positive ARP--- adopt IP The address for MAC Address

First , The host sends... In the form of broadcast ARP request , Based on the known IP Address , request MAC Address . All devices in the broadcast domain can receive request packets , All devices that receive packets will record the source in the packet IP Address and source MAC The correspondence of the address is related to the local ARP The cache table . after , Look at the request IP Address , If it's local IP Address , Will be performed ARP The reply , Local MAC Address inform . If it's not local IP Address , The packet will be discarded directly , after , When sending data again , Give priority to local ARP Cache table , If there are records in the table , Then the information will be sent directly according to the record , If there is no record , Then send ARP Request package acquisition MAC Address .

reverse ARP--- adopt MAC Address past IP Address

free ARP---1、 Self introduction. ;2、 Detect address conflicts .

The physical layer --- Handle the transmission of electrical signals

TCP/IP Model

TCP/IP Protocol cluster

TCP/IP The standard model --- Four layer model

TCP/IP peer model --- Five layer model

PDU--- Protocol data unit

L1PDU

L2PDU

...

L7PDU

application layer --- The data packet

Transport layer --- Data segment

The network layer --- Data packets

Data link layer --- Data frame

The physical layer --- Bit stream

Encapsulation and de encapsulation

application layer --- There is encapsulation in the application layer , Depending on the application

Transport layer --- Port number ---TCP,UDP

The network layer ---IP Address ----IP

Data link layer ---MAC Address --- Ethernet protocol

The physical layer

TCP/IP The model supports cross layer encapsulation , And in the OSI Not in the middle .--- Cross layer encapsulation is generally used to send information between short-range direct connected devices , It can improve the forwarding efficiency .

1、 Cross four layer packaging ---OSPF

2、 Span three 、 Four layer package

SOF--- Frame header delimiter

DSAP--- Indicate what protocol the upper layer of the device receiving the data frame uses to process the data

SSAP--- Indicates the protocol generated by the upper layer of the device that sends the data frame

Control---1、 Connectionless mode ;2、 Connection oriented pattern --- It can realize the fragment reorganization of data packets

IP Address

IPV4---32 Bit binary structure --- dotted decimal

IPV6---128 Bit binary structure --- It's hexadecimal

Network bit --- The network bits are the same , It means in the same broadcast domain

Host bit --- In the same broadcast domain , Use the host bit to distinguish different hosts

Subnet mask --- Continuous 1 And continuous 0 form ,1 On behalf of network bit ,0 Represents the host bit

A,B,C--- Unicast address --- That is, it can be used as a source IP Address , It can also be a goal IP Address .

A:255.0.0.0

B:255.255.0.0

C:255.255.255.0

D--- Multicast address --- Only as a target IP Address using , Cannot be used as a source IP Address using

E--- Reserved address

A:0XXX XXXX---(0-127)1-126

B:10XX XXXX---128-191

C:110X XXXX---192-223

D:1110 XXXX---224-239

E:1111 XXXX---240-255

unicast --- One to one communication

Multicast --- One to many （ The same multicast group ）

radio broadcast --- A pair of all （ All in the broadcast domain ）

stay IP In the address space , Part of it IP The address is called private IP Address （ The private network IP Address ）, The rest is called public IP Address （ Public network IP Address ）--- We habitually use private networks IP The network built by address is called private network , Use the public network IP The network built by address is called public network .--- Private address can be reused , However, uniqueness must be guaranteed within the private network .

A：10.0.0.0-10.255.255.255 amount to 1 individual A Class segment

B：172.16.0.0-172.31.255.255 amount to 16 individual B Class segment

C：192.168.0.0-192.168.255.255 amount to 256 individual C Class segment

special IP Address

1,127.0.0.1-127.255.255.254--- Loopback address

2,255.255.255.255--- Restricted broadcast address --- Only as a target IP Use

3, All the hosts 1---192.168.1.255/24--- Direct address --- Only as a target IP Address using

4, All the hosts 0---192.168.1.0/24--- Network segment （ network address , network number ）

5,0.0.0.0---1, No, IP Address ;2, therefore IP Address

6,169.254.0.0/16--- Local link address / Automatic private address

VLSM--- Variable length subnet mask

192.168.1.0/24

192.168.1.00000000---192.168.1.0/25

192.168.1.10000000---192.168.1.128/25

CIDR--- No inter domain routing

Take the same , Go different --- For binary

192.168.0.0/24

192.168.1.0/24

192.168.2.0/24

192.168.3.0/24

192.168.0.0/22---- HYPERNET

172.16.0.0/24

172.16.1.0/24

172.16.2.0/24

172.16.3.0/24

172.16.0.0/22--- Summary

Generation conditions of direct route ---1, Dual interface UP;2, The interface must be configured IP Address

Get unknown route information of network segment

Static routing ： Routing entries manually configured by the network administrator

Dynamic routing ： All routers run the same routing protocol , after , Routers communicate with each other , Exchange and calculate the routing information of the unknown network segment .

Advantages of static routing ---1, The choice of route is more reasonable ;2, safer ;3, No additional occupation is required Source

shortcoming ---1, Large amount of configuration ;2, Static routing cannot automatically converge based on changes in topology

Basic configuration method of static routing ：

Method 1 ：[r1]ip route-static 192.168.3.0 24 192.168.2.2---- You need to recursively find the interface

Method 2 ：

Extended configuration of static routing

1, Load balancing --- When a router accesses the same target with multiple paths with similar overhead , You can split the traffic and take multiple paths at the same time , Play the effect of superimposing bandwidth .

2, Manual summary --- When a router can access multiple consecutive subnets , If they all pass the same next jump , These network segments can be summarized and calculated , Directly write a static route to the summary network segment , You can reduce the number of routing table entries , Improve forwarding efficiency .

3, Routing black holes --- In summary , If the network segment that does not actually exist in the network is included , It may cause the flow to have no return , Waste link resources .

4, Default route --- A route that does not limit the destination , When looking up the table , If all routes do not match , The default route will be matched .

5, Empty interface routing --- Prevent routing black holes and default routes from meeting and leaving the ring .

1、NULL 0 --- If the outgoing interface of a route points to an empty interface , The datagram matching this route information will be discarded

2、 Matching principle of routing table --- The longest match principle （ The principle of exact match ）

6, Floating static routing