Mạng cơ bản: Mạng hoạt động như thế nào

Mạng là một hệ thống các thiết bị được kết nối với nhau để trao đổi thông tin nhằm hoạt động đúng cách. Điều này có thể bao gồm máy tính xách tay, máy chủ, điện thoại thông minh và hơn thế nữa. Các thiết bị này giao tiếp với nhau thông qua các mạng đặc biệt được gọi là Router và Switch. Khi số lượng thiết bị kết nối với Internet tiếp tục tăng, chúng ta cần hiểu cách chúng giao tiếp với nhau. Trong bài viết này, chúng ta sẽ xem xét các thành phần mạng khác nhau và cách chúng phối hợp để cho phép chúng ta duyệt web, gửi email và nhiều hơn nữa.

Có nhiều loại mạng khác nhau, mỗi loại có mức độ phủ sóng khác nhau. Hãy bắt đầu khám phá các loại mạng khác nhau:

Các Loại Mạng:

LAN – Mạng Cục Bộ

LAN, hay Local Area Network, là một loại mạng nhỏ hơn và được giới hạn trong một tổ chức hoặc gia đình. Ví dụ, số lượng thiết bị kết nối với mạng gia đình của bạn bị giới hạn so với một loại mạng khác. Một mạng trường học, mặc dù lớn hơn mạng gia đình, vẫn được coi là LAN vì nó kết nối nhiều thiết bị trong cùng một không gian vật lý. Điều này bao gồm máy tính, máy chủ, v.v.

MAN – Metropolitan Area Network

MAN là một mạng lưới mở rộng bao phủ toàn bộ thành phố.

Bằng cách kết hợp và kết nối nhiều mạng trong một thành phố, chúng ta sẽ tạo thành một mạng MAN hoặc mạng khu vực đô thị. Loại mạng này toàn diện hơn và bao phủ toàn bộ thành phố. Một loại mạng cung cấp tốc độ dữ liệu nhanh hơn tương đối so với kết nối internet trung bình được gọi là Mạng Khu vực Đô thị, hay MAN.

WAN – Mạng diện rộng

WAN (wide area network) là một mạng máy tính lớn kết nối các mạng nhỏ hơn, chẳng hạn như LAN (local area networks).

WAN là một mạng lưới kết nối nhiều thành phố hoặc quốc gia với nhau để mọi người có thể sử dụng internet hoặc giao tiếp với nhau một cách dễ dàng trên một diện tích rộng lớn. Khi nhiều LAN của một tổ chức được kết nối, nó hình thành một WAN.

WWAN

Basically, the internet is a worldwide area network (WWAN).

WLAN – Wireless LAN

A Wireless LAN, or Wi-Fi for short, is a network that’s typically created by our home router.

A WLAN is a type of LAN that we can connect to wirelessly from our smartphones, tablets, laptops, or any other device. The wireless environment, which uses radio waves to transmit data instead of cables or other physical media, has different characteristics than the wired cable-based network in terms of speed, security and coverage. One of the best advantages to wireless connectivity is that it’s very flexible.

In addition to the network types mentioned above, there are other networks of different sizes or purposes. For example,

• SAN- Storage Area Network.
• EPN – Enterprise Private Network.
• VPN – Virtual Private network.

Networks can be represented in two ways:

Networks are typically represented by a “network topology”, which refers to the way devices on the network are connected. There are two main types of network topologies: logical and physical.

Logical topologies

Logical topologies illustrate the logical aspects of a network, such as IP addresses, the connection between devices, and the routing protocols being utilized.

Physical topology

The physical topology of a network is the way in which it is physically arranged. This includes where devices are placed, what type of cables are used, how many ports are needed, and to which ports/switches servers will be connected. The physical topology is a diagram showing the equipment’s location and purpose in the network.

However, the purpose of a device will result in different network topologies.

Network Topologies

There can be multiple ways to represent devices in a network environment. They can be grouped based on their different purposes.

Starlike Topology

The most popular topology used for LANs is the Star Topology. Star topology works best for smaller networks, like those used by small businesses.

For example, if we only need network connectivity or internet access, we can group the devices in a starlike topology. All the machines in this network are connected to the central HUB. If any node fails, it doesn’t harm or damage the entire network because they are very easy to maintain and grade.

However, the problem with this scenario is the lack of redundancy, which is essential for computer networking.

Mesh Topology

A Mesh Topology is best for a reliable network, such as an ISP – Internet Service Provider. With this design, everything is backed up. So if something goes wrong with a cable or switch, there are other ways to access the internet or wherever you’re trying to connect. Remember that full redundancy means you’ll need more devices and longer cables, equating to higher costs. A full Mesh Topology generally costs more to implement than a Starlike Topology.

Some examples of Mesh Topology are Google Wi-Fi, Google Home or Networks in military devices.

Partial Mesh Topology

The Partial Mesh Topology is a more affordable network topology that only provides redundancy for some of the switches and parts of the network. The other switches are left with no alternative paths.

Hub and Spoke Topology

The Hub and Spoke Topology is utilised frequently in the WAN (internet) design. The three routers in this topology are unacquainted with each other by default. So that data will arrive at its destination, both R1 and R3 will have to send their traffic to R2, who knows how to redirect it correctly. For example, if R1 wants to send traffic to R3, they will do it by sending it through the Hub (R2). The Hub then knows how to process and redirect that traffic.

Network components

The pieces that come together to make a network are:

End-device

Any physical device we use to connect to the internet is known as an end device. This includes PCs, laptops, smartphones, servers and more. The connection can be made through multiple channels, such as electricity, light impulses, or radio waves. We can connect to the Internet wirelessly from our smartphones, laptops, and PCs. If we’re using a laptop or PC, we can also use a Network cable (UTP).

Switch

A Switch interconnects multiple end devices, like computers and printers, within a network (LAN).

This device is popular for its ability to handle many ports, with speeds between 1 and 10 Gbps per port. The switch uses MAC addresses to identify the end devices connected to the network. This makes it easy for you to track which devices are connecting to your network and ensures that only authorized devices can access your data.

Router

A router connects multiple smaller networks (LANs) to form one large network (WAN- Wide Area Network). The Router is a device that connects us to the internet by handling packet delivery from any network source to any destination network. The Router uses IP addresses to identify devices sending and receiving data. A Router typically has between 2 to 5 ports, as opposed to a Switch which can have many more. Additionally, both devices have comparable speeds of 100 Mbps- 10 Gbps, depending on the model.

Firewall

We are better equipped to halt possible virtual break-ins by having a firewall.

Transmission medium

The transmission medium is the means by which information is transmitted, e.g. through a cable or wirelessly.

How do computers communicate over the Internet?

Traffic must have a unique identifier to communicate with sites like Facebook and Google. This is called IP or Internet Protocol. IP, or Internet Protocol, is how we identify a device either in a network or on the internet. This number must be unique. You cannot have two identical IP addresses on the same network or the Internet because it will create a conflict, and your connection will not work correctly.

Growth of the Internet

In recent years, the number of connected devices worldwide has exploded. Did you know that in 2020, there were approximately 50 billion devices connected to the internet? And out of those 50 billion devices, an increasingly high number is part of the Internet of Things (IoT).

The Internet of Things (IoT) describes devices that can collect data from each other and use the internet to communicate. Some examples of common IoT devices include sensors, smart home devices, payment terminals and smart wearables. These devices also need to have an IP address.

IP addresses are of two kinds:

Public IP VS Private IP

Public IP addresses

Just as their name suggests, public IP addresses are used for communication over the internet. Organizations like NIC (Network Information Centre) and IANA register public IP addresses, which are then assigned to Internet Service Providers (ISPs) or other groups.

Private IP addresses

Private IP addresses are normally used in Local Area Networks (LANs), like home or school networks. Consequently, Private IP addresses cannot be found on the Internet. In order to allow computers to communicate with one another over the Internet, a protocol was designed known as NAT (Network Address Translation.) This converts private IP addresses into public IPs.

NAT can improve our network’s security by making it difficult for an attacker to access private IP addresses.

In brief

As the number of devices connected to the internet continues to grow, we must understand how they communicate with one another. This article looks at the different network components and how they work together to allow us to browse the web, send emails, and more. We also looked at how IP addresses play a role in identifying devices and why private IPs are used in local area networks. Understanding how these technologies work is more important as we move into an increasingly interconnected world.