Every device uses two addresses. The MAC address is physically burned into a card in the device. The IP address is set by software based on the network the device is connected to.
每个设备使用两个地址。MAC地址被物理地刻入设备中的一张卡中。IP地址由软件根据设备所连接的网络设置。
看完视频后，在TCP/IP指南中回顾一下这些主题:
IP解决概念和问题
IP Addressing Overview and FundamentalsIP Address Size, Address Space and "Dotted Decimal" NotationIP Basic Address Structure and Main Components: Network ID and Host IDIP Addressing Categories (Classful, Subnetted and Classless) and IP Address Adjuncts (Subnet Mask and Default GatewayNumber of IP Addresses and MultihomingIP Address Management and Assignment Methods and AuthoritiesIP寻址概述和基本原理
IP地址大小、地址空间和“点十进制”表示法
IP基本地址结构和主要组成部分:网络ID和主机ID
IP地址类别(有类、子网和无类)和IP地址附件(子网掩码和默认网关)
IP地址的数目和多重寻址
IP地址的管理和分配方法及权限
>> There are two addresses every device uses: MAC --media access control, and IP -- internet protocol.
每个设备都有两个地址:MAC——媒体访问控制，IP——互联网协议。
MAC addresses are physical addresses are physical addresses burned into the NIC --network interface card -- which is the chipthrough which all network communications enters and exits a machine.
MAC地址是物理地址，是刻入网卡的物理地址，网卡是所有网络通信进出机器的芯片。
MAC addresses are 48 bits long, represented with 12 base 16 hexadecimal characters,and are separated into two sections.
MAC地址是48位长，用12个以16为底的十六进制字符表示，并被分成两个部分。
The first six hex characters represent the manufacturer of the NIC assignedby the I triple E -- the Institute of Electrical and Electronic Engineers.
前六个十六进制字符代表由itriple E(电气和电子工程师协会)指定的NIC制造商。
This OUI -- organizationally unique identifier -- is never duplicated.
这个OUI(组织上惟一的标识符)从不重复。
The last six hex characters, the device ID, is a unique value assignedto a manufacturer to each of its NICs.
最后六个十六进制字符，设备ID，是分配给制造商的每个nic的唯一值。
The I triple E won't give out duplicate blocks of identifiers to manufacturersand the manufacturers won't duplicate the device IDs.
itriple E不会将重复的标识块分发给制造商，而制造商也不会复制设备id。
So we can say that MAC addresses are globally unique.
我们可以说MAC地址是全局唯一的。
No two MAC addresses are the same across the entire world.
全世界没有两个MAC地址是相同的。
IPv4 addresses are logical addresses, bound to NICs through software.
IPv4地址是逻辑地址，通过软件绑定到nic。
They are 32 bit addresses, represented with four base 10 decimal numbers,and are also separated into two sections.
它们是32位地址，用4个以10为底的十进制数表示，并且被分成两个部分。
The first section represents the network ID, the starting string of bits that all nodeson a shared network have in common.
第一部分表示网络ID，这是共享网络上所有节点共有的起始位串。
The second section represents a host ID, a unique string --like the MAC address device ID -- for each host on a shared network.
第二部分代表一个主机ID，一个独特的字符串，就像MAC地址设备的ID一样，每个主机都有一个共享网络的主机。
Unlike MAC addresses, it is not as simple as splitting the two parts down the middle.
与MAC地址不同，它不像将这两部分从中间分开那么简单。
An entity known as a subnet mask -- another 32 bit value --identifies where the breakup of network ID and host ID occurs.
一个被称为子网掩码的实体，另一个32位的值，识别出了网络ID和主机ID的位置。
The subnet mask always has a string of ones, followed by a string of zeros.
子网掩码总是有一串1，后面跟着一串0。
The ones represent network bits and the zeros represent host bits.
1表示网络位，0表示主机位。
In other words, when you line up an IP address with its subnet mask in binary,if there is a one in the subnet mask row, it means that the corresponding bitin the IP address row in the same column is a network bit,shared by all hosts on the same network.
换句话说，当您以二进制形式将IP地址与其子网掩码排成一行时，如果子网掩码行中有一个掩码，则意味着同一列中的IP地址行中对应的位是一个网络位，由同一网络中的所有主机共享。
A zero for a subnet mask bit means that the corresponding bit in the IP address rowin the same column is a host bit.
子网路掩码位的零表示同一列中IP地址行的对应位是主机位。
In the next video, we'll see exactly how this subnet mask is used.
在下个视频中，我们将确切地看到这个子网掩码是如何使用的。
转载于:https://www.cnblogs.com/sec875/articles/10344618.html
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