What is DOCSIS?
Cable Internet is still one of the popular broadband internet access systems in the U.S. In this system, the existing cable television infrastructure is used to provide internet access to the user, using either a coaxial cable or a hybrid fiber-coaxial cable. In order to access internet over coaxial cable, the user must have a cable modem, a device that is responsible for modulation and demodulation of the digital signals and allows communication between the user’s computer and the ISP (internet service provider). DOCSIS is short for Data Over Cable Service Interface Specification. It is an international telecommunications standard developed by CableLabs with significant contribution from several network and communication companies such as Cisco, Broadcom, ARRIS, Comcast, Intel, Netgear, Motorola, etc. All the cable modems in the market are designed and developed as per the DOCSIS standards as these standards lay out the rules and regulations for internet access over existing cable television infrastructure. Starting with DOCSIS 1.0, which was released in March of 1997, each iteration of the DOCSIS standard has introduced (or standardized) several features in terms of fundamental functionality, transfer speeds (upstream and downstream), IPv6 support etc. So, it is very important to check for the DOCSIS version of your cable modem if you want to know the maximum upstream and downstream speeds you can expect from your modem.
What is DOCSIS 3.0?
The DOCSIS version 3.0 was released in August of 2006 and offered a significant upgrade from the previous DOCSIS versions (DOCSIS 2.0 was released in December of 2001). Until DOCSIS 2.0, the downstream speeds are limited to 40Mbps, while the upstream speed in DOCSIS 2.0 was 30Mbps. The DOCSIS 3.0 version redefined these speeds and introduced the high-speed internet over cable for the first to the users. In DOCSIS 3.0, the downstream speed limit was 1Gbps and the upstream speed limit was 200Mbps. DOCSIS 3.0 also introduced support for IPv6. Due to the increased speeds, DOCSIS 3.0 introduced data transfer through multiple channels. At least 4 channels for upstream and downstream is required but the maximum no. of channels can go as high as 32 for downstream and up to 8 for upstream. All the features introduced in earlier versions of DOCSIS (2.0, 1.1 and 1.0) such as VoIP, QoS, etc. are further improved in DOCSIS 3.0.
What is DOCSIS 3.1?
The DOCSIS 3.0 brought very high-speed internet to the users and it allowed several internet related activities such as streaming videos, gaming, browsing the internet, etc. to become very fast. DOCSIS 3.1 was released in October of 2013 and it introduced further improvements to DOCSIS 3.0. The first and foremost upgrade was the upstream and downstream transfer speeds. The maximum downstream transfer speed in DOCSIS 3.1 is 10Gbps and the maximum upstream transfer speed is 1 – 2Gbps. Apart from the transfer speeds, DOCSIS 3.1 also introduced new channels bandwidths and modulation techniques. While DOCSIS 3.0 used 6MHz channel bandwidth for downstream and 6.4MHz channel bandwidth for upstream, DOCSIS 3.1 used 192MHz channel bandwidth for downstream and 96MHz channel bandwidth for upstream. Coming to the modulation, DOCSIS 3.0 used 256-level QAM (Quadrature Amplitude Modulation) and DOCSIS 3.1 uses 4096-level QAM. Some other upgrades in DOCSIS 3.1 are enhanced security features (protection against malware), low latency (important for online gaming), improved VoIP call quality and sleep mode (for low power consumption).
Pros and Cons of DOCSIS 3.0 vs 3.1
Pros of DOCSIS 3.0
Cheaper to implement Enough if you have slow internet plan Variety of modems are available from different manufacturers Cost of modems is low
Cons of DOCSIS 3.0
Not future proof Slow downstream and upstream speeds Less secure Latency is high
Pros of DOCSIS 3.1
Future proof Fastest internet speed possible over cable internet Low latency Sleep mode (for low power consumption) Integrated security features
Cons of DOCSIS 3.1
Not as widespread as DOCSIS3.0 Cost of modems is higher
Difference between DOCSIS 3.0 vs 3.1
Let us now see some of the differences between DOCSIS 3.0 vs 3.1 in the following table.
DOCSIS Versions Compared
The following table shows different DOCSIS versions along with their main specifications and features.
When is DOCSIS 4.0 Coming?
After the success of DOCSIS 3.1, CableLabs started working on the next version of DOCSIS with the aim of symmetrical multi-gigabit speeds (both downstream and upstream), enhanced security and reliability and also low latency. An initial specification, called DOCSIS 3.1 Full Duplex was released in October of 2017. It was rebranded as DOCSIS 4.0 and an updated specification was released in 2019. As of today, there are no devices that are compatible with DOCSIS 4.0 specification. We predict it will take another 5 – 7 years for DOCSIS 4.0 to become mainstream and available to the users.
Conclusion: DOCSIS 3.0 vs 3.1 – Which is Best for You?
This depends on two things: your current internet speeds and budget. If your current internet plan has less than 1Gbps downstream transfer speeds and you don’t intend to upgrade your plan anytime soon, then DOCSIS 3.0 is more than sufficient as you can save a couple of bucks on it. But if you are planning for downstream speeds over 1Gbps and want to utilize your internet to the maximum, then look for cable modems which are DOCSIS 3.1 compliant. These modems are definitely future proof (up to 5 years) and you can easily get the maximum downstream speeds that is possible over cable internet right now. That being said, DOCSIS 3.0 modems are cheaper than DOCSIS 3.1 modems and if you want to use that extra downstream and upstream speeds, then you have to spill your pockets. Comment * Name * Email * Website
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