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

First, what is the Internet?

The network integrates the whole Internet into a huge supercomputer to realize the comprehensive sharing of computing resources, storage resources, data resources, information resources, knowledge resources and expert resources. The fundamental feature of grid is not necessarily its scale, but the sharing of resources and the elimination of resource islands.

2. Network equipment:

1. Hub (Hub)-an HUB is in a collision domain and a broadcast domain

Advantages: cheap and easy to operate

Disadvantages: shared type, can not meet multiple people to access at the same time, there is a conflict domain

Transmission type:

− simplex: always can only complete one direction of data transmission, such as BB machine, telegram, can only receive but not send.

− half-duplex: data transmission can only be completed in one direction at the same time, such as walkie-talkie, can not be sent when receiving, can not be received when sending.

− full-duplex: data transmission in two directions can be completed at the same time, such as telephone and mobile phone, which can be sent and received at the same time.

2. Switch (switch)-A port on a switch is a collision domain and a switch is in a broadcast domain

Advantages: multi-user simultaneous access and full-duplex support

Disadvantages: unable to complete some special functions disadvantages: unable to complete some special functions (NAT), there is a broadcast domain

Action

Access of − end-user equipment

Basic security functions of −

Isolation of − broadcast domains (VLAN): the essence of vlan is to isolate broadcast domains

Data type

− unicast: a pair of −

Multicast: one-to-many broadcast: one-to-all

3. Router-A port is a collision domain and a port is a broadcast domain

Advantages: can build a large network, high security advantages: can build a large network, high security advantages: can build a large network, security, independent broadcast domain, collision domain

Disadvantages: too few interfaces, high price, disadvantages: too few interfaces, high price

Function:

− routing protocol support

− path selection

− data forwarding

− wide area network access

Third, knowledge points

Collision domain: a collection of all workstations connected to the same wire, or a collection of all nodes on the same physical network segment, or a collection of nodes competing for the same bandwidth on Ethernet, such as a particular device sending a packet on the network segment, forcing other devices on the same network segment to notice this. At the same time, if two different devices try to send packets, there will be a conflict. After that, both devices must resend the packet, and only one device can send it at a time.

Broadcast domain: broadcast is a way of spreading information, which means that a device in the network sends data to all other devices in the network at the same time. The range to which this data can be broadcast is the broadcast domain (Broadcast Domain). To put it simply, a broadcast domain is a collection of all the devices in the network that can receive the same broadcast message.

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