Document Maintainers: Chris Shipley
Overview
We answer a lot of questions about what type of bandwidth is appropriate. The answer is a little more complicated depending on the use case.
Identifying Terms
Latency
Latency is the metric used to define how long it takes for data to traverse through all the connections it has to from source to end point. The lower the latency, the faster the response time. You can have a low-latency network that doesn’t have a lot of bandwidth. You can have a high-latency network that has a lot of bandwidth. Most high speed Internet connections you see advertised on TV for homes or small offices are high latency, high bandwidth connections. The more expensive versions most people don’t use (but are usually commercial) are fiber based (but not always, I’ve helped deploy WiMAX in the Boston area).
Bandwidth
This is the amount of data that can be pushed through a low or high latency. They are definitely related, but they are different metrics. What we are most often advertised to (DSL, Cable) are billed as high bandwidth. But high bandwidth with a high latency is not the same type of network performance we see in high bandwidth low-latency networks.
Synchronous vs Asynchronous
Most of the bandwidth we are advertised is asynchronous: the download speed is greater than the upload speed. Synchronous bandwidth has the download and upload at the same level.
Guaranteed vs Best Effort
Most of the Internet connections we receive advertising on are Best Effort (Cable, FiOS, DSL). Look for terms like “up to 300mbps”. This means they have a best effort service to deliver that speed to you, but are relying on a technology variable in its ability to deliver that speed to you and depends on factors like neighborhood congestion or distance to a NOC. A guaranteed bandwidth (fiber, WiMAX) is just that, guaranteed to be at the level to which you are paying for and relies on technology to deliver that to you.
Applications for bandwidth types
High latency, high bandwidth (Cable, 4G, FiOS) – Best Effort
These are typically asynchronous connections, i.e. 300 mbps down / 20 mbps up (FiOS is synchronous like 500 mbps down/ 500 mbps up). Having these in our homes gives us a bit of an unreasonable expectation for what the technology is capable of in a larger environment. The technology doesn’t scale particularly well. It’s also usually a variable bandwidth. When you have a lot of people connected and the available bandwidth suddenly drops, you have to make a sacrifice somewhere: it usually shows symptoms like “My computer says I’m online, but that call was just dropped”. Or “the video in this call is really slow and the audio is unintelligible”. It does have it’s uses, though, especially when dealing with these use cases:
- Streaming video – Amazon, Netflix, etc – it’s really good with this because when you have great bandwidth available to you, your system can cache the video of the next few minutes you haven’t watched yet. Once your video starts, you don’t even notice when your bandwidth goes down or up because it’s constantly caching future minutes you haven’t watched.
- Web browsing – most web browsing benefits well from this type of connection
If your office doesn’t use VoIP, live video meetings, etc very often, you can get away with this. Unless you’re looking at a lot of people (over 20) – and in that case if you can separate your VoIP (not video, just voice) traffic over a low latency, low bandwidth connection this can be a viable solution.
Yes, FiOS is fiber, but it’s not guaranteed bandwidth. It is the step between this category and the next, it only promises what cable promises with best-effort service, but does deliver more consistently.
Low latency, high bandwidth (fiber) – SLA Guaranteed
Fiber, and other types of connections our clients don’t deal with, falls under this category. It’s typically the most expensive. The connections are typically synchronous. This is just the best type of Internet connection all-round, but it’s not necessary for all people pending their use case. You should do this type of connection if you consistently rely on the following:
- Over 20 people consistently using your connection
- VoIP Service
- Live video calls (Zoom, Skype, WebEx, GoToMeeting)
- Hosting Webinars
These connections are best for live video because you need to have the packets travel as fast as possible between end points. A live video feed can’t cache your yet-unwatched video because it hasn’t been recorded yet. This also gives more bandwidth available on upload for more people if it’s a synchronous connection, benefitting file sharing systems like Dropbox, OneDrive, Egnyte, etc.
Low latency, low bandwidth (fiber, HFC, T1) – SLA Guaranteed
These networks have a limited application, but for those applications they are very good at what they do. They are typically synchronous. You might be looking at HFC (hybrid fiber over coax) or fiber for this type of connection. The low bandwidth may not be great for a large number of people trying to browse the web these days, but it’s fantastic at VoIP (Voice Over IP). A blend of these types of bandwidth with a high-latency, high bandwidth connection might be a good compromise to save your company money over needing a low latency, high bandwidth network – pending your need.
Applications:
- Voice Over IP
- Backup connection for business critical apps
High latency, low bandwidth (DSL, 3G) – Best Effort
Even though it’s billed out as a high speed Internet, DSL is a fairly low bandwidth option in today’s landscape. You can also get wireless 3G connections as well. It does have it’s place though, and it’s good for:
● Web browsing
● Small offices (5 or less)
● Backup connections
More Control
Firewalls
Some firewalls can give you more control over your bandwidth and how it’s used. Proper configuration of the firewall can manage applications and give them a different priority over other traffic. Or even route specific traffic over a different type of Internet connection. Sadly, this usually is not your $100 router from Staples or Best Buy.
Summary
By comparison, a 100mbps/100mbps fiber connection (low latency, high bandwidth, synchronous) will perform better and more consistently than a 300Mbps/20mbps cable connection (high latency, high bandwidth, asynchronous) – even though advertising leads us to believe that the larger the bandwidth number the better, it’s not all about bandwidth. As the landscape of our use of the Internet changes and we add more interactive features (like live video), the need for more upload bandwidth becomes painfully clear when we have Internet connections that are inadequate to the task at hand, especially in offices with more staff.