Linux System Network Knowledge--first part

1. Initial Network

　　The network system is a huge system, which involves routing, security, wireless, language, data center and so on.

① Network basic knowledge: related to the development of the network, some concepts of the network, the introduction of the route Exchange

② Introduction to the OSI seven layer model

③ Introduction to the TCP/IP protocol cluster, including the TCP/IP three-time handshake and four-wave waving process

④ VLSM concept of variable eldest son net

2. Network topology

Network topology is the physical layout of the various devices that are interconnected by transmission media. Topology Refers to the specific physical, i.e. real, or logical, virtual arrangement of the members of a network. If the connection structure of the two networks is the same, we say that their network topology is the same, although their respective internal physical wiring, the distance between nodes may be different.

In essence, the network topology is similar to the network device composed of a connection diagram, through the device connection diagram can determine the connection of the device, in order to facilitate the failure, based on the topology map to locate the fault point faster. Before you configure a network device, be sure to plan for network equipment, that is, how network devices are connected, thus forming a connection diagram of a network device, a network topology (similar to a map of network equipment Planning)

3, the concept and development of the network

Simple understanding of the concept of the network: is the computer network, there are many electronic devices connected to build a network of IP.

the evolution of the network development process: The Simple network is connected with two network devices by two wires.

In a simple network environment, there is the concept of IP address, similar to the name of the human, easy to connect

An IP address is present in the network as an identifier for any node in the network

The interconnection network, because the network scale grows, needs a more scientific network topology,

So there's the HUB (it's a bus)

However, the hub will be the concept of conflict domain, a certain period, the Hub interface, only one user to establish a data link, and the destination to communicate, the other interface is in the state of listening (CSMA/CD technology)

Because of the above problems, as the development of the network to introduce the switch equipment, can effectively solve the above problems.

4, switch

Vendor: Dlink,h3c,cisco, all servers communicate with each other on the switch. Switches (English: switch, meaning "switches") is a network device used for the forwarding of electrical signals. It provides a unique electrical signal path for any of the two network nodes that access the switch. The most common switch is the Ethernet switch. Other common telephone voice switches, fiber switches, and so on. HTTP://BAIKE.BAIDU.COM/LINK?URL=AB0QKNPOYQCBX44601L8EMPFSMGD4BW Eoyrmx7ax1dxj_-e6nfhvqmdct15m753baptl_ 95xb8q9c-2aed8fsk
What are the functions and characteristics of the switch? All terminal devices connected to a port on a switch are on a network segment (called a broadcast domain).

and a network segment will have a unified network identity that will generate broadcast consumption device CPU resources

A switch can isolate conflict domains, and each port is a conflict domain

End-User device access

Basic security Features

Isolation of broadcast domains (VLAN)

Introduction to broadcast domains:

When a switch is connected to multiple terminal devices, multiple terminal devices are in the same network segment, and an identical network segment means that a broadcast domain broadcast mode does not transmit or receive messages as needed, but that all machines in a network segment are unconditionally received, so when broadcast information is generated in large quantities, Consumes the CPU resources of the network segment machine to receive broadcast information, that is, the so-called broadcast storm two different broadcast domains are not able to communicate, because they belong to the different two network segments hint: The same network segment is a unified network identity.

5, router (router)

Router (Router), is connected to the Internet in each LAN, WAN equipment, it will automatically select and set the route according to the situation of the channel, the best path, in order to send the signal. OSPF routing protocol, large enterprise RIP, static route (route) Http://baike.baidu.com/link?url=4AD4Cz9hy6QNpi5LfdqHM5Zb_0dVc6eo 6pu5ym7a5qufogowetybiz7qhetg5_boowi46nsenvunap5o2ntd3k CISCO, WAN, public network interconnection requires routers, routers do not forward private network addresses. The essence of the router is to isolate the broadcast domain, which is the communication between the two broadcast domains, that is, to make the two different network segments connect with each other.

Description of the function and features of the router:

Routing protocol forwarding route is similar to real life from A to B may need to walk, in the car, in the plane to reach the B, the whole process in the network corresponding data transfer process is called routing.

Therefore, when a data message is passed across different network segments to the destination address, the process of passing the data can be called routing, or it can be seen as the path of each passing data.

Data forwarding, maintaining a routing table (equivalent to a map)

Routers typically place a router on the network exit as a gateway

WAN Link Support

Agreement:

A protocol is a convention or call rule designed by both parties to communicate.

HTTP protocol, TCP/IP protocol family.

Must be:

1, the TCP/IP protocol three handshake and four break process.

2. How the HTTP protocol works (overstating).

1.1 Brief introduction of Campus network

Waiting to be updated ...

Linux System Network Knowledge--first part