Enhance the grid, whether it is operations or development to know the network Knowledge 9/(a)

First of all, in this statement: Thank heqing brother to the information.

The idea of learning the Web:

• Focus on Learning:

Network knowledge of the system is also very large, involving a lot of content, if you want to master the network and master operations, pay the energy to be very large, and not necessarily pay and harvest in direct proportion, it is recommended to learn how to transport the students, can learn a little bit of network knowledge, but do not need to delve into the network of specific command configuration

① Learning Network Fundamentals can complement the knowledge of the network part of the system to facilitate understanding of system architecture deployment

② Learning Network Basics facilitates better coordination with network departments in the event of network planning and failure problems

③ Future operation and maintenance industry belongs to the trend of skill, ignoring a certain aspect alone, it is not particularly advantageous for its development.

First Knowledge Network

Network system is a huge system, involving the routing switch, security, wireless, voice, data center and so on many aspects, so there are a lot of content need to learn and understand, but lofty high-rise flat, so the basis for the system operation and maintenance is the most important, for the network learning should start from the foundation, network knowledge of the beginning.

Network Basic Learning System

Cisco Course System Overview (CCNA), although the knowledge content is not too much, the training cycle generally around 1 weeks, but covers most of the knowledge content, for a preliminary understanding of network knowledge, master network related configuration, basically has been very satisfied, especially the system operation and maintenance personnel

Description

For the system operators, the above knowledge can be learned, CCNA learning difficulty is not very large, and the learning cycle is short, for the rapid becoming a system operations engineer, the best network, has been enough.

If time and energy are limited, it is advisable to learn the following knowledge as the cornerstone for stepping into network knowledge

① Network basic knowledge: related to the development of the network, some concepts of the network, the introduction of ②osi seven-layer model of the introduction of ③TCP/IP protocol cluster, including tcp/three times handshake and four wave of the process ④vlsm variable eldest son net concept 

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)

The concept and development of 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:

• A simple network that connects two network devices with two wires

In a simple network environment, there is the concept of IP address, similar to the name of a person, easy to access the Internet; An IP address is present in the network as an identifier for any node in the network

• Interconnected networks, because of the size of the network, need a more scientific network topology, so there is a hub (is a bus)

However, the hub will be the concept of conflict domain, a certain period of time, the hub interface, only one user can build several

According to the link, and the destination end of the communication, the other interface is in the state of listening (CSMA/CD technology)

As a result of the above problems, as the development of the network to introduce the switch equipment, can effectively solve the problems arising from the above

Switches (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.

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function and feature description 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 end devices, multiple end devices are in the same network segment, and an identical network segment represents a broadcast domain

Broadcast mode does not transmit or receive messages as needed, but all machines in a network segment are unconditionally received, so when broadcast information is generated, it consumes the CPU resources of the network segment machine to receive broadcast information, the so-called broadcast storm

Two different broadcast domains are not able to communicate because they belong to a different two network segment

Tip: The same network segment is a unified network identity

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)

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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 characteristics of the router

    1. Routing protocol forwarding route similar to real life from A to B may need to walk, in the car, in order 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.    2. Data forwarding will maintain a routing table (equivalent to a map)    3. The router will typically place a router on the network exit as a gateway    4. WAN Link Support

Protocol

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

HTTP protocol, TCP/IP protocol family.

Must be:

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

2 , HTTP How the Protocol works (overstating).

Http://baike.baidu.com/subview/36190/12517929.htm

OSI seven-layer model and protocol-Package Encapsulation solution Package Details Http://www.tudou.com/programs/view/sP9JY_KranA/TCP Three-time handshake four-time disconnection principle process detailed http://www.tudou.com/ programs/view/xjhcdedzqa8/

The Division of Network hierarchy structure

Brief introduction of Campus network

Hierarchical description of the network

• Core layer: The core layer of the function is to achieve optimal transmission between backbone networks, the backbone of the design task is often the focus of redundancy capacity, reliability and high-speed transmission.
• Aggregation layer: The aggregation layer is a cluster or a community information aggregation point, is connected to the access layer and the core layer of network equipment, for the access layer to provide data aggregation \ transport \ management \ Distribution processing. The aggregation layer provides policy-based connectivity to the access layer, such as address merging, protocol filtering, routing services, authentication management, and so on. Network segments and network isolation can prevent some network segment problems from spreading and affecting the core layer. The aggregation layer can also provide the interconnection between the Access Layer virtual network, control and restrict access layer to the core layer, ensure the core layer security and stability.
• Access layer: The access layer usually refers to the part of the network directly facing the user connection or access. The purpose of the access layer is to allow end users to connect to the network, so the access layer switches have low cost and high port density characteristics.

Enhance the grid, whether it is operations or development to know the network Knowledge 9/(a)