網絡拓撲 令牌環網 以太網

A topology explains how physically the network is designed or what is the structure of the network. These designs are both physical and logical. There are many network topologies 4 like Bus, Star, Ring, and Mesh. But only two types of topologies are used in Ethernet i.e Bus and Star. So, let's know about these two topologies:

拓撲結構說明了網絡的物理設計方式或網絡的結構。 這些設計是物理的和邏輯的。 有許多網絡拓撲4，如Bus，Star，Ring和Mesh。 但是以太網中僅使用兩種類型的拓撲，即總線和星形。 因此，讓我們了解以下兩種拓撲：

1) Bus Topology

1)總線拓撲

All computers in a bus topology are connected to a wire. Whenever a computer sends a computer frame, it goes to all the computers available in the topology, but it only accepts the computer whose MAC address matches the frame.

總線拓撲中的所有計算機都連接到電線。 每當計算機發送計算機框架時，它將轉到拓撲中可用的所有計算機，但僅接受MAC地址與框架匹配的計算機。

The biggest disadvantage of bus topology is that if the wire ever gets damaged, then communication of all computers stops simultaneously. Computers have no means of communication separately from each other.

總線拓撲的最大缺點是，如果電線損壞，則所有計算機的通信將同時停止。 計算機沒有彼此分開的通訊方式。

2) Star Topology

2)星型拓撲

All hosts in Star Topology are connected to a switch or hub and they send frames to each other through hosts hubs and switches. Hubs are not intelligent. When frames are sent through the hub, the hub sends those frames to all the hosts and the host that receives the MAC address matches it.

星型拓撲中的所有主機都連接到交換機或集線器，它們通過主機集線器和交換機相互發送幀。 集線器不是智能的。 當通過集線器發送幀時，集線器會將那些幀發送到所有主機，并且接收到MAC地址的主機將與之匹配。

Switches are intelligent devices. The switches maintain the address table of all hosts. So whenever a host sends a frame, it is not sent to everyone and goes to the same host whose MAC address matches. The biggest disadvantage of the star topology is that if the switch or hub spreads, all the networks fail.

開關是智能設備。 交換機維護所有主機的地址表。 因此，每當主機發送幀時，它都不會發送給每個人，而是轉到其MAC地址匹配的同一主機。 星型拓撲的最大缺點是，如果交換機或集線器擴展，則所有網絡都將發生故障。

以太網幀 (Ethernet Frame)

Ethernet data link layer technology. In the data link layer, the data is known as frames. The size of a frame can be from 64 bytes to 1522 bytes. There are some fields in the frame whose size is fixed. The information about these fields is given below.

以太網數據鏈路層技術。 在數據鏈路層中，數據稱為幀。 幀的大小可以從64字節到1522字節。 框架中的某些字段的大小是固定的。 這些字段的信息在下面給出。

Preamble

前言

The size of this field is 7 bytes. This field is used for synchronization purpose.

該字段的大小為7個字節。 該字段用于同步目的。

Start of Frame

幀開始

The size of this field is 1 byte. This field shows the starting point of the frame.

該字段的大小為1個字節。 此字段顯示幀的起點。

Destination MAC Address

目的MAC地址

The size of this field is 6 bytes. This field holds the destination host's MAC address.

該字段的大小為6個字節。 此字段保存目標主機的MAC地址。

Source MAC Address

源MAC地址

The size of this field is also 6 bytes. This field source hosts the MAC address.

該字段的大小也是6個字節。 該字段源托管MAC地址。

802. 1Q Tag

802. 1Q標簽

The size of this field is 4 bytes. This field is optional. This tag is used to show VLAN configuration.

該字段的大小為4個字節。 該字段是可選的。 此標記用于顯示VLAN配置。

Length

長度

The size of this field is 2 bytes. This field shows the size of the whole frame.

該字段的大小為2個字節。 此字段顯示整個幀的大小。

Payload

有效載荷

The size of this field can be from 42 bytes to 1500 bytes. This is your actual data.

該字段的大小可以從42字節到1500字節。 這是您的實際數據。

CRC (Cyclic Redundancy Check)

CRC(循環冗余校驗)

The size of this field is 4 bytes. This shows the errors in the field frame.

該字段的大小為4個字節。 這顯示了字段框架中的錯誤。

Inter-Frame Gap

幀間間隙

The size of this field is 12 bytes. It shows the time gap between field frames.

該字段的大小為12個字節。 它顯示了場幀之間的時間間隔。

翻譯自: https://www.includehelp.com/computer-networks/types-of-network-topology-in-ethernet-connection-and-its-frame.aspx

網絡拓撲 令牌環網 以太網