What’s the Bandwidth Ceiling on an Internet / WAN circuit?

It seems like every single year bandwidth needs are rising, recently compounding by >30% annually! Meanwhile, researchers broke the world record for data transmission speed over a fiber line, sending data at 402 terabits per second. All of this lends itself to the question - what is the theoretical “bandwidth ceiling” when buying a dedicated internet / WAN circuit from a major ISP? What are the constraints on what they can deliver? 

Understanding this “bandwidth ceiling” is crucial for network planning and optimization. While much can be achieved with smart network engineering and capacity planning, there's also a hard cap on the total volume of data any one channel can carry at a given time. In this blog article, the Lightyear team will put the bandwidth ceiling under the microscope and unpack everything you need to know about how much you can theoretically get from an ISP circuit.

What is the Bandwidth Ceiling, Anyway?

The bandwidth ceiling refers to the maximum amount of data that can be transmitted over a network or communication channel in a given amount of time. It is measured in bits per second (bps), kilobits per second (Kbps), megabits per second (Mbps), or gigabits per second (Gbps). When you use a wired internet service, you will see line speeds associated with your package. These are a great indicator of the bandwidth ceiling for that specific service. No matter how optimized your network or how great your services, you usually can't get more bandwidth than the maximum advertised by the line you are using!

Several factors can affect the bandwidth ceiling for any given service:

• Network Hardware / Cables: The quality and capacity of hardware components such as routers, switches, and cables can limit the maximum bandwidth regardless of service provider performance.

• Technology Standards: Different network technologies and protocols have varying maximum bandwidth capacities. For example, Ethernet standards like 100Base-T and 1000Base-T (Gigabit Ethernet) have different bandwidth ceilings.

• Service Provider Limits: Internet service providers (ISPs) and telecommunication companies often impose bandwidth caps or limits on their customers. These can serve as an artificial ceiling.

• Regulatory Constraints: Government regulations may also limit bandwidth, sometimes just for specific applications or services.

• Environmental Factors: Physical conditions such as electromagnetic interference, distance between network nodes, and signal attenuation can also impact your effective bandwidth ceiling.

What are the Maximum Available Bandwidths on the Market?

Understanding the bandwidth ceiling starts by understanding the readily available bandwidths. These change all the time as technology evolves. However, as of mid-2024, this is the general state of bandwidth availability for dedicated circuits from major ISPs:

• 100 Mbps is available almost everywhere.

• 1 Gbps is available almost everywhere.

• 10 Gbps is widely available in most major markets.

• 100 Gbps is available in select markets.

• 400 Gbps is available in select markets.

• There are experimental networks offering speeds of 1 Tbps or more.

Does that mean you can walk into an ISP tomorrow and demand 100 Gbps? Not quite. Remember that not all speeds are available from all carriers, and some carriers throttle bandwidth. And even if a carrier does offer 100 Gbps lines, they may only provide them in some areas. Most 100 Gbps and 400 Gbps require specialized hardware and are primarily sold as IP transit circuits in data centers, making these speeds harder to get in commercial buildings. Also, remember that bandwidth is different than speed, and other metrics like latency, jitter, and packet loss will matter too!

However, we are seeing interesting new developments. Combining multiple 100 Gbps links is gaining traction, for example, using 8 x 100 Gbps circuits for 800 Gbps throughput. This developing strategy could be a great way for enterprises to tailor their available bandwidth more effectively and prevent the bandwidth ceiling from impacting mission-critical operations.

An Overview of Wired Connection Types

Now, let's take a little trip down memory lane regarding wired connections. 

Dial-up (DS0): Provided a whopping 56k to 64k wired connection using copper telephone lines. It was first introduced in the late 1980s. While it is still around (are you surprised?), it's a legacy technology that is being phased out. Today, we only really see it used in POTS lines, typically for emergency connectivity in infrastructure like elevators. The biggest incremental increase in speed for dial-up, at least for a few years, was the jump from 56K dial-up to 64K via ISDN.

DSL lines: First introduced in the late 1990s and now being phased out, these can still be found widely. Speed for these lines was highly dependent on the type of DSL installed. There have been several evolutions in the DSL type over the years. Typically, DSL would be in the 1 Mbps to 20 Mbps range but can reach as high as 100 Mbps. However, it still relies on copper telephone lines. DSL modems/routers connected to phone lines delivered the massive benefit of “always on” internet instead of dial-up requiring the user to reconnect for each session.

T1 (DS1): DSL may have been the iconic internet connection of the '90s and '00s, but it wasn't the only one. T1 provided 1.5 Mbps for a single T1, and 12 Mbps could be achieved by bonding eight T1s. Like DSL, it relies on copper telephone connections and is currently being phased out. Most modern bandwidth options rely on coaxial cables or fiber lines.

T3 (DS3): Introduced in the late 1980s, this is still available, with speeds of 45 Mbps. This high-capacity, reliable connection is typically used as a backbone connection by ISPs. A router with a DS3 interface is required.

Coax Cable: Although introduced in the 1990s, it is still available in most markets. Speeds vary from 1 Mbps to 1 Gbps or higher. Coax uses the coaxial cable infrastructure originally developed for cable television services. A cable modem is needed to terminate the coax cable and deliver internet services via Ethernet and WiFi.

Fiber Optic Ethernet: This is today's dominant wired connection, with speeds from 10 Mbps to 100 Gbps, or more. Powered by fiber optic cable, fiber has been available in most major markets since the 2000s. The speeds that different carriers offer vary greatly. Fiber optic cable terminates to carrier-grade equipment on site, with several handoff options based on speed, distance, and user preference. There are several options for terminating equipment, like routers, SD-WAN equipment, firewalls, and switches.

The Lightyear platform is used to request and procure all kinds of modern wired connectivity services. In our experience, enterprise businesses often request and install coax broadband and dedicated fiber. The coax broadband services used are virtually identical to residential services. If you're curious, you can read more about what's trending in connectivity.

How to Beat the Bandwidth Ceiling 

As we've seen above, the underlying network infrastructure and carrier-offered connection speeds determine the bandwidth ceiling. To get the best performance (100 Gbps) from your connectivity, several factors must align:

1. The end user’s equipment must be capable of processing at 100 Gbps throughput. Factors like CPU, RAM, and the Ethernet interface must be considered.

2. The site’s infrastructure must be suitable and efficient, including switches, WiFi, and cable distance.

3. The premise firewall/perimeter security devices can also affect bandwidth, as can the termination equipment (routers or SD-WAN devices)

4. The equipment that the provider installs at the customer site must also be capable of handling 100 Gbps. Service providers use ROI (Return on Investment) calculations to determine the type of equipment they install in buildings, and it isn’t always capable of handling 100 Gbps.

5. The fiber optic/transport network also matters. This network brings the service through the poles or underground to the customer site from the service provider. Everything must be 100 Gbps capable.

6. The service provider’s edge router and core router need to have 100 Gbps capability.

In short, even if your chosen service provider can support 100 Gbps throughput from your site to the Internet, whatever you’re connecting to must also be capable of 100 Gbps. So, to achieve 100 Gbps at your site, all the factors listed above must be in place and purchased on the other end of whatever you’re connecting to.

If you need to procure the speediest bandwidth options in your area, why not try the Lightyear platform? After all, slow and unreliable internet can be a major revenue killer for businesses, so evaluating your options with software can perhaps help you save time and avoid pain down the line.