Digital Signal Processing, Internet, IT, Telecomunications

How internet works? (Part 1, data center)

This is the first of a series of posts showing operation of internet. The first part is about data center.

What is data center?

Is a structure where are processed and stored internet data like sites, videos, archives, images, etc. Also transmit these data to internet through optic fibers. It is very important to operations of IT (Information Technology) sector, for that has a high level of security and restrict access.

There are three types of data centers.

  • Private data center (PDC): Used by corporations and government agencies, government sites are stored in this type.
  • Internet data center (IDC): Is managed by companies like Google, Apple and etc, which provide services of website hosting, internet connection, e-mail service, content storage, etc. IDCs are much bigger and consume more energy than PDCs.
  • Virtual data center: It is the option to organization which can’t, or don’t want, spend with physical infrastructure. Has the same functions and can be stored in one or more physical data centers.

How it works?

Server

Inside a data center there are many servers. A server is a computer without mouse, keyboard and monitor, whose function is manage content and transmit to clients.

Server’s memory stays in a solid state device (SSD). Electrical e-Library and all its content are in a SSD inside a server. The latter is in a data center of Locaweb in São Paulo city.

In addition to servers, a data center also has many switches, routers and memory storage, they serve as auxiliary components. The equipment is stacked in closets or stacks.

DNS

How a content in a server is accessed? Every computer, smartphone or any object connected to internet has an IP (Internet Protocol) address. This is a set of numbers analog to a home address. Every domain has an IP address, which indicates the server, it is difficult for a human to remember a series of numbers. The domain has a URL name like http://www.electricalelibrary.com/. DNS translate domain name in IP and vice-versa, receives the domain’s name written by somebody in a browser and translate to IP to find the server.

One server can store many different sites, so domains need a host reader to distinguish sites in a same server.

Architecture

This is a typical data center architecture. The core layer is formed by routers, aggregation layer is formed by interconnection and server switches, the later are linked with servers. Access layer is where stay the servers, some sources put access switches in this layer.

The router is the network’s gateway, connects with other networks, determines which is the best route to transmit data package and send packages to other networks.

While the switch makes connection with all devices in a network.

Infrastructure and security

Data center consumes a lot of energy, needs to operate uninterrupted because if there is a blackout, all the content inside will be inaccessible by internet. For that, has UPS system, with its own substation, reserve batteries and emergency generators in case of blackout. In addition high power sources to equipment.

All these servers and auxiliary components produce heat, therefore need cooling air system to not damage servers. In addition to humidity control, protection against fire and natural disasters, alarm system and camera closed circuit. This is an example showing inside data center facility. NOC room is network operations center.

More details about components will be explained in the future.

 

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About Pedro Ney Stroski

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