Original Address: https://blog.csdn.net/lu_embedded/article/details/80519898
618 electricity providers Festival, two-eleven shopping carnival, in the end is what tens of thousands in support of spike activity? This must mention has been incognito CDN, and attention is not CSDN, but CDN, CDN, CDN! It stands for Content Delivery Network, ie, content delivery network.
CDN is that in the end what the hell, we had to start from the Buddhist sutras ......
1300 years ago, the monk teacher and student learn to trek thousands of miles apart, after Hong eighty-one hard, all the way Daguai upgrade, and ultimately to fruition, Wukong crowned "fighting over the Buddha."
After 1300, the Internet has opened Journey to the West, raids the monastery official online line, to learn just open the site, click to download, mortal can also easily made Scriptures.
At first, Tang master feel quite hard year's worth paying, lament things change, the spell is no match for high-strength and technological progress.
However, many four continents men and women, get together and go to the official website to download raids the monastery by the book, website overwhelmed, believers complain incessantly, the magic and the Tathagata resorted to "Scacleup + Scaleout" Heart, expansion Leiyin official website, still puzzled, then Wukong sent a check exactly.
Wukong eyes, took a long while to check a crystal clear reason, the original believers in order to access Mimi Lei Yin network, you need to defeat four monsters:
The first strange, Shuri magic
"Shuri Magic" also known as "the first kilometer magic," holding web server access to the Internet Journey intersection of bandwidth, this bandwidth determines the speed of access can be provided for the believers and the amount of concurrent access.
The second strange, fine backbone
"Backbone fine" Journey hidden in the Internet long-distance transmission routes and haunted IDC, backbone, metro, access and other caves, use the "delay" and "congestion" Two witchcraft practices.
The third strange, interconnected demon
Journey Internet covering four continents, continents ministries operate independently of the network, "Internet demon" the ability to sow discord, let interconnect bandwidth between the continent and the continent become a bottleneck.
Fourth strange beast in the end
“末里兽”又称“最后一公里兽”，蹲守在上网信徒的家门口，把持用户访问西游互联网的通路，收取买路钱，钱少只能走羊肠小道。
悟空看罢大怒，原来是这些妖孽作怪！
于是拔下一根毫毛，使出“CDN”大法，变作几百只小猴子，一声令下，每猴背熟一些经文，纷纷潜入到各大部洲的 IDC 山洞中，就近为善男信女们提供讲经服务，这些小猴子被俗称为“cache猴”。
小猴子们基于这样的规则干活：
A．当某个信徒需要阅读经书，大家就挑选能最快到达信徒家的猴子前去讲经（可能距离最近，也可能是路最好走）；
B．如果某部经书被很多信徒需要，它就会被距离这些信徒最近的小猴子烂熟于心。
可是猴子很多又生性顽劣，管好还是很费神的，于是悟空叫来了师父和师弟们帮忙，师徒同心，其利断金。
沙和尚任劳任怨，悟空让他承担“分发服务”：
老沙的主要职责是将经书内容从雷音寺中心向各部洲的“cache猴”推送和存储，承担实际的佛经流量全网分发工作和面向最终信徒的阅读请求服务。
猪八戒肠肥肚圆，悟空让他承担“负载均衡”：
八戒负责对所有发起阅经请求的信徒进行访问调度，确定提供给信徒的最终实际访问地址，告诉信徒那个小猴子最适合他。
唐三藏高瞻远瞩，悟空请他承担“运营管理”：
Monk responsible for the supervision of daily affairs, revenue accounting, check the status of the team, analyze, and bear with major clients - Buddha "facilitating" role relationships.
In the co-operation of mentoring four, four monster is defeated, the Buddha of heart disease cure, world common people to learn Mimi drops online.
Raids the monastery earn pours, has introduced a new service, only the original scriptures download can now be viewed online through the book, you can also live video, watch online Buddha preaching.
So Tang master's CDN service is only available from the original file transfer acceleration services, and later increased to speed up streaming services, web browsing acceleration services.
Since then, the world is no longer difficult to get through, get Fozu Jia Wukong award, an upgrade from "fighting over the Buddha" to "stop fighting wins Buddha"!
Well, the story Journey to the West is finished, small partners also understand what is a CDN.