Shulou(Shulou.com)06/01 Report--

Personal summary of some of the basic network technology concepts and commands, you can refer to, in order to further study.

Anti-counterfeiting code: sword edge from sharpening, plum blossom fragrance from bitter cold

I. Hierarchy

1. Osi7 layer

Physical layer, data link layer, network layer, transport layer, session layer, presentation layer, application layer

2.TCP/IP Layer 5

Physical layer, data link layer, network layer, transport layer, application layer

3.TCP/IP Layer 4

Network interface layer, network layer, transport layer, application layer

4. agreement

Application layer:

http https telnet dns dhcp smtp pop3 nmbd smdb ftp tftp

Transport Layer:

tcp udp

Network layer:

ip arp rarp icmp igmp

5. The role of vlan

Logically divide broadcast domain, control broadcast, improve security

6. The role of trunk relay

Direct communication between different vlans and the same vlan

7. The role of single-arm routing

Communication between different vlans

8. The role of Ethernet channels

Load Balancer of Link, Fault Tolerance

The Role of VTP

Add, delete, rename vlan from one point to maintain the entire network

10. private address

10.0.0.0-10.255.255.255

172.16.0.0-172.31.255.255

192.168.0.0-192.168.255.255

The Role of ARP

Resolves MAC addresses based on known IP addresses

12. Switch forwarding principle

Learning (based on unknown source mac address)

Broadcast (based on unknown destination mac address)

Unicast (based on known destination mac address)

Switches forward data according to mac tables

13. Forwarding Principle of Router

In the encapsulation of the whole data, the source ip and destination ip remain unchanged, the source mac and destination mac change, and the router forwards the data according to the routing table.

II. Related Orders

1. duplex and speed

Three additional models:

User mode: switch>

Privileged mode: switch>enable

Global mode: switch#config terminal

Interface mode: switch(config)#interface fastethernet 0/1

The same is true for routers: switch to router

Configuration in interface mode:

duplex:duplex full (or half, auto)

Speed: speed 100 (or 1000, auto)

2. Command before configuration:

Idle for a while, return to the initial interface:

line con 0

exec-timeout 0 0

Disable DNS queries: no ip domain-lookup

Enable message synchronization:

line con 0

logging sync

3. static and default routing

static: ip route destination subnet mask next hop

Default: ip route 0.0.0.0 0.0.0.0 Next

4. ARP related commands:

View arp cache: show arp or show ip arp

Clear arp cache: clear arp-cache

Binding: arp ip address mac address arpa

5. view command

View current configuration information: sh run

View saved information: sh start

View version information: sh version

View hostname: hostname

View mac address table: show mac-address-table

View interface information: show int f0/2

To view switching information for an interface: show int f0/2 switchport

6. saved commands

write or capy run start

7. various cryptographic

Console password (for local login)

line con 0

password password

login

Privileged password:

enable password

enable secret

vty password (used for Telnet login)

line vty 0 4

password password

login

8. Static vlan settings

Divide vlan:

vlan database

vlan 2

exit

Add interfaces to vlan:

int f0/2

switchport access vlan 2

View: Show vlan brief

9. Configuration of trunk

int f0/2

switchport mode trunk

10. The VTP Configuration

Global mode: vtp domain qq (name optional)

View vtp information: show vtp status

gns3 configure vtp under vlan database

11. Configuration of single-arm routing

Take f0/0 as an example:

int f0/0.2

encapsulation dot1q 2

ip add 192.168.2.1 255.255.255.0

12. DHCP Configuration

In global mode:

ip dhcp pool qq

network 192.168.2.0 255.255.255.0 (address pool defining 2.0 segment)

default-router 192.168.2.1 (defines default gateway)

dns-server 202.106.0.20 (defines dns server address)

13. Ethernet Channel Configuration

int f0/2

channel-group 2 mode on

View Ethernet channels: show ethernet summary

14. Three-layer switching

A, single-arm routing itself will become the backbone link of the network, easy to form a bottleneck.

b. Sub-interfaces are still dependent on physical interfaces and are not flexible in practice.

c. You need to check the routing table every time you forward between VLANs, which is a serious waste of equipment resources.

Communication between vlans using layer 3 switching technology

Step Command:

Enable routing: ip routing

Virtual interface configuration ip (acting as gateway):

For example: int vlan 2

ip add 192.168.1.1 255.255.255.0

no shutdown

Configure routing interfaces:

Configure in interface mode:

no switchport

Layer 3 switch configuration trunk: Enter interface mode

For example: int f0/2

switch port trunk encapsulation dot1q

switch mode trunk

d. dhcp relay

Configure gateways on the corresponding virtual interfaces

For example:

int vlan 2

ip helper-address ip address of dhcp server

Attachment: down.51cto.com/data/2368086

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