Vswitch and SIMPLE NETWORK COMMUNICATION

1. Basic Network Devices

(1) network interface card (NIC, NetworkInterfaceCard)

Function: Provides the network communication capability for the PC, converts the data transmitted by the device to a format that can be recognized by other devices on the network, and transmits data through the network media.

The sender converts the data to be sent from the computer system into a bit stream transmitted over the network cable.

At the receiver, the bit streams received from the network cable are duplicated to form the data that can be processed by the computer system.

Determine whether data is sent to yourself

Send and control data streams between computer systems and network cables

MAC address: physical address, also known as lan address. In a network, any device (such as a computer, router, or vswitch) has its own unique MAC address to uniquely identify itself in the network, no two devices in the network have the same physical address.

Note: Most MAC layer addresses are built by the device manufacturer inside the hardware or the ROM chip in the NIC. Place the network interface card in the computer's motherboard, and the computer has a MAC address. The MAC (MediaAccessControl) address is a 6-byte binary string. It is usually written as a hexadecimal number separated by a colon. The first three bytes represent the vendor code, the last three bytes are allocated by the vendor. For example, 00: E0: FC: 20: 0A: 8C.

When a device sends information to another device, you can use a MAC address to establish communication with the other device. The source computer sends the information with the MAC address of the target computer to the network. The NIC (receiving system) of each device in the network checks the MAC address of the information, check whether it is your MAC address. If the information does not match, the NIC ignores the information. If the information is not received, the NIC copies the information.

(2) twisted pair wires (TwistedPair, TP)

Definition: consists of two copper wires with an insulating protective layer. Put one or more pairs of twisted pair wires in an insulated sleeve tube to form a twisted pair cable.

Performance: relatively soft, easy to build in irregular places such as corners. It is mainly used to transmit analog sound information and digital signal transmission. In most applications, the maximum cabling length of twisted pair wires is 100 m. According to the distance, the data transmission rate can generally reach 10 mbps-100mbps. However, the new technology allows a limited range of twisted pair wires to reach a data transmission rate of Mbps or even higher.

Category: Shield twisted pair (ShieldedTwistedPair, STP), relatively high price, difficult to install than unshielded twisted pair cable, similar to coaxial cable, with shielding function; UnshieldedTwistedPair, UTP), no shielding function, low cost, and very popular applications. This network cable is used in most small and medium-sized enterprises, such as LAN and Internet cafe LAN.

(3) connector

Function: connect UTP and STP is RJ-45 connector (commonly known as crystal head), one end can be connected to the computer network interface card, the other end can be connected to the Hub, switch, router and other network equipment.

2. Create a twisted pair Cable

(1) preparation tools:

Twisted pair wire, RJ-45 clamp, RJ-45 connector, cable Tester

(2) Production Process: There are four steps: strip, line, plug, and line.

Step 1: strip the wire. Use the wire cutting tool of the wire clamp to cut the end of the twisted pair wire, and then extend the end of the twisted pair wire into the wire stripping tool port, so that the wire head touches the front baffle plate, and then moderately tighten the clamp while slowly rotating the twisted pair wire, enable the cutting edge to split the protection rubber of twisted pair wires, and remove the terminal head to peel off the protection rubber. Note: the force of the clamp cannot be too large; otherwise, the core wire is cut off; the length of the wire is 13mm ~ 15mm, not too long or too short.

Step 2: line management. Twisted Pair wires are twisted by eight colored wires and arranged in parallel by white orange, orange, white green, blue, white blue, green, white Brown, and brown, after finishing the sorting, use the cutting edge to restore the front end. The front end is arranged clockwise.

Step 3: plug the wire. After the eight lines are combined, cut them together with a diagonal clamp and keep the length of about 14mm. One hand holds the crystal head, and one side of the crystal head has shrapnel down. The other hand holds the twisted pair wire and inserts the prepared wire into the cable trough in the crystal head with a little force, the top of the eight wires should be inserted into the top of the cable trough. When inserting the twisted pair wires into the RJ-45 connector, pay attention to the "Orange White" line to the first foot of the RJ-45.

Step 4: press the wire. After confirming that all the wires are in place, place the crystal head in the clamp slot of the crimping tool, and press the crimping tool several times to compress the wire head.

(3) direct connection network cable

The two ends have consistent line order. It is used for interconnection between different types of RJ45 interfaces (MediaDependentInterface and MDIX). Generally, interfaces between hosts and routers belong to MDI, and interfaces between switches and hubs belong to MDIX.