What Are Access Networks?

Network Interface Adapter

The network interface adapter enables a computer to attach to a network. Since there are so many different types of networks, network adapters are used so that the user can install one to suit the network to which they want to attach.

Network interfaces also usually have an address associated with them. One machine may have multiple such interfaces.

These interfaces are essentially the physical gateways that connect devices to the Internet.

Most machines then have external ports which network cables can be plugged into. The type of access network depends on the physical media involved. Here are some common access networks:

1. Digital Subscriber Line (DSL)
2. Cable Internet
3. Fiber To The Home (FTTH)
4. Dial-Up
5. Satellite
6. WiFi

We’ll go through the what and how of most of these access network in the next few lessons.

But first, how is the speed of a network measured? What exactly is the unit of speed of a network? Let’s have a look!

Transmission Rates

The rate at which data is transmitted from one point to another in a network is called the transmission rate. In other words, the speed of the network is its transmission rate.

The smallest unit that digital data can be divided into is a bit: a $1$ or a $0$. Transmission rates are measured in units of bits/sec. However, since bits/sec is a really small unit, multiples/prefixes are commonly used. Common prefixes and their interpretation is given below:

For example, a speed of $240$ Mbit/second means that $240,000,000$ or $240$ million bits get transmitted every second!

There are essentially two ways that data flows in a network: from an end system or to an end system. The outgoing transmission rate is called the upload rate, and the incoming transmission rate is called the download rate.

Some networks have varying upload and download transmission rates, called asymmetric transmission rates. This is useful because traffic going out from end hosts generally consists of small requests which solicit comparatively much larger responses.

Note You can check the upload and download transmission rate of your Internet connection from https://www.speedtest.net!

Quick Quiz!

---

Now that we’ve covered the basics, let’s move on to some detail about the physical media that actually make up these networks.