What is DOCSIS?

If you want to upgrade some of the hardware in your network setup, the modem is one of the most important components to consider. As important as the router, the modem determines whether you can make the most of your Internet connection or have to pay for unused bandwidth.

What is DOCSIS?

DOCSIS stands for Data Over Cable Service Interface Specification. It is a telecommunications standard developed in the 1990s by CableLabs, a nonprofit cable research corporation. This standard is intended for high-speed data transmission using existing coaxial cable (CATV) infrastructure.

Previously, cable companies that wanted to provide Internet to customers would have to use incompatible standards, which was a problem for both the company and the customer.

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DOCSIS enabled local cable providers to evolve into ISPs, eventually providing both cable TV and Internet over a single connection, which is great considering the future of Television cable. Simply put, if you get your Internet connection from your local cable provider then you are using DOCSIS.

Since its introduction in 1997 with DOCSIS 1.0, the standard has gone through many versions, each adding higher data transfer speeds or better security. DOCSIS 1.0 provides theoretical download and upload speeds of 40Mbps and 10Mbps respectively. This was improved with DOCSIS 2.0 in 2001, which had maximum theoretical download and upload speeds of 40Mbps and 30Mbps respectively. This means a significant improvement for connections like VoIP calling or anything that uses a two-way connection.

DOCSIS 3.0 launched in 2006 and offers much higher potential download speeds of 1Gbps and upload speeds of 200Mbps. This is also when DOCSIS started implementing channel binding, allowing modems to use multiple up or downstream channels for transmission. It also implements 128-bit AES encryption to the previously insecure 56-bit encryption in older DOCSIS formats.

The next version, DOCSIS 3.1, was released in 2013 and improved power management and network stability. Data transfer speeds also increased to 10Gbps download and 1.5Gbps upload.

The latest version of the standard, DOCSIS 4.0, launched in 2017 but has yet to be widely adopted by consumers. It retains the same download speed, but upload speed can be up to 6Gbps.

Compare DOCSIS 3.1 and DOCSIS 3

DOCSIS 3 and 3.1 are the two most popular versions today. DOCSIS 1.0 and 2.0 modems have been discontinued for a long time, so you may be using a DOCSIS 3.0 modem.

Here is a quick summary of the differences between them.

Besides data transfer speeds, one of the biggest differences between DOCSIS 3.0 and DOCSIS 3.1 modems is the number of channels they can use for upstream or downstream transmission.

As mentioned before, DOCSIS 3.0 allows modems to use multiple upload or download channels for higher speeds. Compatible modems are required to use at least 4 channels for both upstream and downstream connections. However, many modems can support up to 32 channels for download and 8 channels for upload. They are often referred to in "download x upload" format such as 4x4, 16x4, 24x8 or 32x8.

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On the other hand, DOCSIS 3.1 requires a minimum of 32 channels for download and 8 channels for upload (32x8). This means that even slow DOCSIS 3.1 modems are faster than leading DOCSIS 3.0 modems.

The channel system is also structured in DOCSIS 3.1, which contributes to higher data transfer speeds. So while a 32x8 DOCSUS 3.0 modem can theoretically provide download speeds of 1.4GBPS, a 32x8 DOCSIS 3.1 modem can go up to 10Gbps.

Is DOCSIS 3.1 needed?

Although DOCSIS 3.1 modems are faster than 3.0 modems, the bandwidth of your Internet connection will determine whether you can use that speed or not.

If you have a 500Mbps download connection and a 30Mbps upload connection, just a 16x4 DOCSIS 3.0 modem is enough. If you have a faster Internet connection, you'll need a DOCSIS 3.0 modem to get the most out of your bandwidth.

However, if your Internet connection provides download speeds of 800Mbps or more, you should spend more money to buy a DOCSIS 3.1 modem. Technically, DOCSIS 3.0 can be pushed to 1Gbps, but almost all ISPs require DOCSIS 3.1 modems.

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It's best to buy a modem that's faster than your current Internet connection provides, as that allows you to upgrade your Internet package without needing to change the hardware later.

The prices of cheap, slow and faster modems don't differ much, so a little extra cost for the modem isn't too bad. Of course, the router also plays an important role (there is a difference between a modem and a router), but it cannot do much if the modem cannot handle the Internet connection bandwidth.

Which model should I choose?

As mentioned above, unless you have an 800 Mbps or higher Internet connection, you should be fine with the DOCSIS 3.0 model. Depending on Internet speeds, DOCSIS 3.0 modems may be available for several more years. However, a DOCSIS 3.1 modem is a must if you have a Gigabit Internet connection.

Although purchasing a DOCSIS 3.1 modem will be future-proof, depending on your Internet connection, it may be possible to save a few hundred thousand by purchasing a DOCSIS 3.0 modem today. However, if you don't mind the additional cost, a faster DOCSIS 3.1 modem isn't a bad idea.

Samuel Daniel

Update 03 May 2024