Take you to the HCNA Ethernet base

1. Several common physical transmission media are briefly described.

>1. Twisted pair Wire (Twisted Pair) : Twisted pair consists of 8 lines of different colors divided into 4 pairs, and the ends consist of a RJ-45 crystal head. The paired two strands are twisted together to offset each other from each other to increase the distance between the two lines. Ordinary twisted-pair wire transmission distance of the maximum is 100m. In order to increase the distance of the transmission, it is generally necessary to increase the transmission distance by means of an intermediate access switch or a device such as a hub. There are generally two types of common standards.

namely: 56-8a and 56-8b

56-8b : Orange white orange , green white blue , blue white green , brown white Brown (for easy memory, I divided the 12 characters into four groups. The 56-8B standard is used in practical use.

56-8a : Green white green, orange white blue, blue white orange, brown white Brown. (Less use, no introduction here)

56-8b There are two different kinds of lines: Straight and Cross lines ( PC and router belong to the same kind of network device )

Straight line: Used to connect different network devices. ( eg: pc-switch,pc-hub;router-switch,router-hub)

intersection line: Used to connect the same network device. ( eg: switch-switch,hub-hub,pc-pc,switch-hub,router-pc,router-router)

>2. Invert line: used to implement a connection from a host to a router console serial communication (COM) port. If you need to connect the computer for console control, you need to connect the computer to the end of the switch interface to convert to 9-pin serial female, and some laptops are not 9-pin serial port male, that will need to be 9-pin serial port to the USB port to the adapter, transfer to the USB port, that is, debugging equipment is the prompt COM port

>3. Optical Fiber: made of glass and plastic, it is a waveguide that transmits light from one end to the other, consisting of a core and a cladding, which is used to transmit light, and the cladding layer restricts the light to the core. Optical fiber is mainly divided into single-mode and multimode. Single-mode fiber can transmit light signal at high speed, while multimode fiber can transmit multi-channel light. Therefore, the cost of single-mode fiber is much more expensive.

2.LAB :

650) this.width=650; "style=" width:702px;height:652px; "title=" 12.png "alt=" wkiom1yxwvrabg55aapbigbekkm424.jpg "src = "Http://s3.51cto.com/wyfs02/M00/74/43/wKiom1YXWvrAbG55AAPBIgbEKKM424.jpg" height= "648" width= "650"/>

AR1 the configuration:

Enter system View

[Huawei]sysname AR1// Device naming

[Ar1]int gigabitethernet 0/0/1// Enter Interface

[AR1-GIGABITETHERNET0/0/1]IP address 10.1.1.1// Configuration IP Address

SW1 the configuration:

Enter system View

[Huawei]sysname SW1// Device naming

[ar1]interface vlanif 1// Enter vlanif 1 Interface

[AR1-VLANIF1]IP address 10.1.1.254// Configuration IP Address

Layer Two switch , only one management can be configured IP

Test :

[sw1]ping-a 10.1.1.254 10.1.1.1// with the original address Ping you can avoid the default Ping is starting with an interface Ping , but it doesn't matter here.

PING 10.1.1.1:56 Data bytes, press Ctrl_c to break

Reply from 10.1.1.1:bytes=56 sequence=1 ttl=255 time=10 ms

Reply from 10.1.1.1:bytes=56 sequence=2 ttl=255 time=50 ms

Reply from 10.1.1.1:bytes=56 sequence=3 ttl=255 time=40 ms

Reply from 10.1.1.1:bytes=56 sequence=4 ttl=255 time=10 ms

Reply from 10.1.1.1:bytes=56 sequence=5 ttl=255 time=50 ms

---10.1.1.1 ping statistics---

5 packet (s) transmitted

5 packet (s) received

0.00% Packet Loss

Round-trip Min/avg/max = 10/32/50 ms

Test connectivity complete!!!

Packets : 650) this.width=650; "style=" width:719px;height:490px; "title=" 34.png "alt=" wkiom1yxwywbtpa5aaoc1wy7twu807.jpg "Src=" http://s3.51cto.com/wyfs02/M02/74/43/wKiom1YXWyWBtpA5AAOc1wy7tWU807.jpg "height=" 482 "width=" 650 "/> data message format for requests and responses of ICMP messages:

0 7 15 31

Type	Code	Checksum
Identifier		Sequence number
Data ... ..

Summary & Configuration Ideas

1. It is better to hand over the eye than times.

2. for two-layer switch, many times can only configure a management IP, for management purposes.

3. When configuring the IP address, Huawei, third devices can be directly behind the number of bits, for Cisco's device requires a complete configuration of the mask.

Configuration ideas:

>1. first of all, we need to name the device before configuration, this is to ensure that we later in the configuration of the device is easy to distinguish, when the device is more efficient to distinguish, this should develop a habit.

>2. Enter the system after trying, we want to do with what, into what, only into the configured permissions, such as: IP address configuration, enter the interface, and then configure the IP address, VLAN configuration, create a VLAN to configure VLAN permissions and so on. This is a general configuration idea that can be extended to other configuration modes.

>3. when the configuration is completed, we can use Ping (based on ICMP protocol) to do the test, but often we in the back of the test can only ping pass is just the most basic step, many times we have to pay attention to its principle, Ping Tong has the truth, Ping does not pass the reason, to do so, In order to improve quickly. Don't just be fooled by appearances.

>4. try to take a look at the open source software wireshark This software crawl data packets to do analysis, deepen the understanding of the Protocol.

Take you to the HCNA Ethernet base