Cloud Math: Converting Network Throughput to Network Consumption

ByJanuary 26, 2016
NetworksOne of the challenges in moving from an on-premise data center into the cloud is capacity planning. Common elements monitored on-premise for capacity planning include the utilization of CPU, RAM, storage, and network. At iland, our Enterprise Cloud Services billing is also based upon the consumption of CPU, RAM, storage, and network.

On-premise, it is common for network utilization to be measured in the network throughput, or megabits per second (Mbps). When your network does not have sufficient throughput to support the application in your data center, the result is network congestion. Network congestion can lead to poor application performance, end-user frustration, and even application outages.

One of the advantages of moving your applications into the iland Cloud is that you get to take advantage of a reliable, high-performance data center network with ample spare throughput both within the data center network and to the Internet. We want you to be able to experience the benefits of our amazing network. So, rather than limit your throughput to some contracted level of bandwidth like a cable company might, we decided to recoup the costs for our network by measuring gigabytes (GB) transferred to and from the Internet over the month.

Internal communication between your VMs within the iland cloud is included as part of the service. Data transfer to and from the Internet is the only bandwidth that is measured for billing. When planning for running your applications in the cloud, all you need to do is estimate what your needs are to get an average monthly throughput for your Internet connection and apply some math to convert that number into an estimated network consumption value.

In addition to the quick table I provide here, I explain the math behind my calculations below the table.

Average Monthly Throughput (Mbps) Expected Monthly Consumption (GB).

1 Mbps 329 GB
5 Mbps 1643 GB
10 Mbps 3285 GB
20 Mbps 6570 GB
40 Mbps 13140 GB
100 Mbps 32850 GB

Here is a spreadsheet formula you’re welcome to use which given the throughput value (in cell A1) in megabits per second converts the value to gigabytes per month:

=ROUNDUP(A1 * (((((60 * 60) * 24) * 365) / 12) * (10^6)) / (8 * (10^9)), 0)

Allow me to explain the formula and values in the table above. The expected monthly consumption value comes from using the throughput value in Megabits per second (Mbps) and converting that value to Gigabytes (GB) transferred over a month. For all calculations we’re using the standard definitions of the Mega and Giga prefixes (e.g. 1 Megabit is 1,000,000 bits, 1 Gigabyte is 1,000,000,000 bytes), and 1 byte is equal to 8 bits.

Because months can have 28, 30, or 31 days in them, I decided to calculate the annual consumption and divide by 12 to get a monthly value. I ignored leap years in this calculation as it did not add a noticeable difference to the final values. Finally, all consumption values are rounded up to the nearest whole number.

Start with determining the number of seconds in a month:

60 seconds per minute
× 60 minutes per hour
× 24 hours per day
× 365 days per year
÷ 12 months per year
= 2,628,000 seconds per month

Next calculate the bits per gigabyte:

1,000,000,000 bits per gigabit
× 8 bits per byte
= 8,000,000,000 bits per gigabyte

Convert the throughput from megabits per second into bits per second:

average throughput (megabits per second)
× 1,000,000 bits per megabit
= average throughput (bits per second)

Now we know how many bits are passing through the network every second. Multiply by the number of seconds in a month so we know how many bits would pass through the network each month:

average throughput (bits per second)
× 2,628,000 seconds per month
= consumption (bits per month)

Finally we convert the bits per month value into gigabytes per month so the number is more reasonable:

consumption (bits per month)
÷ 8,000,000,000 bits per gigabyte
= consumption (GB per month)

The final value we get out of the calculations is the estimated monthly bandwidth consumption. It’s useful whether you are trying to estimate a pay-as-you-go price or come up with a good starting point for reserving network resources.

Looking for a cloud service that provides straight-forward, predictable pricing combined with visibility into your cloud costs and billing through an intuitive console? Check out http://www.iland.com/services/pricing/ and contact us so we can show you how.
Jeff Polczynski

Jeff Polczynski

Jeff Polczynski is the Director of Solutions Architecture at iland. Formerly, Jeff was a Network Engineer with iland who helped design and build the network infrastructure upon which the iland Cloud runs. Jeff loves to regale IT war stories from his 20 years as a Network and Security Engineer in government, financial services, and service provider sectors. Today he helps iland customers by tailoring the iland services into a personalized cloud solution.