Posts Tagged 'Data Transfer'

August 12, 2015

Network Performance 101: What is latency, and why does it matter?

We’ve all been there. Waiting for a web page to load can be so frustrating that we end up just closing out. You might ask yourself, “Hey, I have high-speed Internet. Why is this happening to me?” Well, there are a lot of factors outside your control that … control page loads. And whether you have an online store, run big data solutions, or have your employees set up on a network accessing files around the world, you never want to hear that your data, consumer products, information, or otherwise, is keeping you from a sale or slowing down employee productivity because of slow data transfer.

So why are some pages so much slower to load than others?
It could be that poorly written code or large images are slowing the load on the backend, but slow page loads can also be caused by network latency. This might sound elementary, but data is not just floating out there in some non-physical Internet space. In reality, data is stored on hard drives … somewhere. Network connectivity provides a path for that data to travel to end users around the world, and that connectivity can vary significantly—depending on how far it’s going, how many times the data has to hop between service providers, how much bandwidth is available along the way, the other data traveling across the same path, and a number of other variables.

The measurement of how quickly data travels between two connected points is called network latency. Network latency is an expression of the amount of time it takes a packet of data to get from one place to another.

Understanding Network Latency
Theoretically, data can travel at the speed of light across optical fiber network cables, but in practice, data typically travels slower than light due to the variables we referenced in the previous section. If a network connection doesn’t have any available bandwidth capacity, data might temporarily queue up to wait for its turn to travel across the line. If a service provider’s network doesn’t route a network path optimally, data could be sent hundreds or thousands of miles away from the destination in the process of routing to the destination. These kinds of delays and detours lead to higher network latency, which lead to slower page loads and download speeds.

We express network latency in milliseconds (that’s 1,000 milliseconds per second), and while a few thousandths of a second may not mean much to us as we’re living our daily lives, those milliseconds are often the deciding factors for whether we stay on a webpage or give up and try another site. As consumers of high-speed Internet, we like what we like, and we want what we want when we want it. In the financial sector, milliseconds can mean billions of dollars in gains or losses from trade transactions on a day-to-day basis.

Logical conclusion: Everyone wants the lowest network latency to the greatest number of users.

Common Approaches to Minimize Network Latency
If our shared goal is to minimize latency for our data, the most common approaches to addressing network latency involve limiting the number of potential variables that can impact the speed of data’s movement. While we don’t have complete control over how our data travels across the Internet, we can do a few things to keep our network latency in line:

  • Distribute data around the world: Users in different locations can pull data from a location that’s geographically close to them. Because the data is closer to the users, it is handed off fewer times, it has a shorter distance to travel, and inefficient routing is less likely to cause a significant performance impact.
  • Provision servers with high-capacity network ports: Huge volumes of data can travel to and from the server every second. If packets are delayed due to fully saturated ports, milliseconds of time pass, pages load slower, download speeds drop, and users get unhappy.
  • Understand how your providers route traffic: When you know how your data is transferred to users around the world, you can make better decisions about where you host your data.

How SoftLayer Minimizes Network Latency
To minimize latency, we took a unique approach to building our network. All of our data centers are connected to network points of presence. All of our network points of presence are connected to each other via our global backbone network. And by maintaining our own global backbone network, our network operations team is able to control network paths and data handoffs much more granularly than if we relied on other providers to move data between geographies.

SoftLayer Private Network

For example, if a user in Berlin wants to watch a cat video hosted on a SoftLayer server in Dallas, the packets of data that make up that cat video will travel across our backbone network (which is exclusively used by SoftLayer traffic) to Frankfurt, where the packets would be handed off to one of our peering or transit public network partners to get to the user in Berlin.

Without a global backbone network, the packets would be handed off to a peering or transit public network provider in Dallas, and that provider would route the packets across its network and/or hand the packets off to another provider at a network hop, and the packets would bounce their way to Germany. It’s entirely possible that the packets could get from Dallas to Berlin with the same network latency with or without the global backbone network, but without the global backbone network, there are a lot more variables.

In addition to building a global backbone network, we also segment public, private, and management traffic onto different network ports so that different types of traffic can be transferred without interfering with each other.

SoftLayer Private Network

But at the end of the day, all of that network planning and forethought doesn’t amount to a hill of beans if you can’t see the results for yourself. That’s why we put speed tests on our website so you can check out our network yourself (for more on speed tests, check out this blog post).

TL;DR: Network Latency
Your users want your data as quickly as you can get it to them. The time it takes for your data to get to them across the Internet is called network latency. The more control you (or your provider) have over your data’s network path, the more consistent (and lower) your network latency will be.

Stay tuned. Next month we will be discussing Network Performance 101: Security, where we’ll discuss all things cloud security—including answering your burning questions: Can other people see or access my data in a public cloud? Is my data more prone to hackers? And, what safeguards do SoftLayer have in place to protect data?


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