Published: 03 Oct 2013
BYOD is all the rage these days. According to a recent Cisco survey, 78% of U.S. white-collar workers use a mobile device for work purposes, and 65% of the respondents say that those workers require mobile connectivity to do their jobs.
Much has been written about the benefits of bring your own device (BYOD) for both workers and companies, as well as the swarm of security requirements that BYOD engenders. However, the problem of corporate network bandwidth consumption has taken a bit of a back seat. Meanwhile, a recent Gartner Inc. study found that 80% of recently installed corporate wireless networks will become obsolete in the next year because of poor infrastructure planning.
Fortunately, there are things you can do to prevent BYOD from wreaking havoc on the corporate network: You can add and upgrade network resources, and you can control or restrict access to devices, sites and applications.
Corporate network bandwidth 101
First, it's important to define bandwidth because the term is widely used and abused. I was recently in a meeting where someone said that an entire hospital only used 200 MB of bandwidth. This statement begs the question, "What in the heck were you measuring?" One radiological survey can consume multiple gigabytes, and one patient record can far exceed that.
Others express corporate network bandwidth as a port utilization percentage. To say a port is only utilized 20% of the time and therefore doesn't require much bandwidth is analogous to saying, "I'm only in the car 20 minutes a day and therefore only need a car that goes 20 miles an hour." It's not how often a port is used, but how fast and reliable the port is when you need it.
The correct definition of bandwidth is the overall capacity of a channel or circuit to pass bits of data. Thus, a 1 gigabit (Gb) connection refers to one gigabit of bandwidth, which can be consumed by any number of resources with access to that connection. If that connection's access is controlled by a wireless access point (WAP), then any device that connects to the WAP will share that bandwidth, and the total corporate network bandwidth available to all the devices remains 1 Gb.
Beyond corporate network bandwidth, another consideration is the number of packets passed. Packets passed will tell us the amount of data that is moving across the circuit. If a 1 Gb circuit is shared by 10 users, then each user has up to 1 Gb, assuming no one else is transmitting data. If all the users are transmitting data, then their speed will decrease based on sharing the packets that the pipe can forward over the gigabit connection; approximately one tenth of the bandwidth, or about 100Mb/s.
The more users that share a network connection, the greater the potential for bottlenecks. Imagine multiple lanes of traffic converging on a single tollbooth, where the toll booth represents a shared channel. A truck will take longer to pass through the toll booth than a car. Likewise, packets come in various sizes depending on the payload, or what is being transmitted. And just as all lanes don't have the same number of cars converging on the tollbooth, neither will packets converge on a channel at the same rate.
BYOD dramatically increases the number of cars hitting that toll booth, which can only process cars at a fixed rate. Today, users typically have 2.8 devices, according to the same Cisco stud. But in 2016, that number is expected to increase 18% to 3.3 devices per user.
In the case of the toll booth, to process more cars and decrease the wait times, you would need to add more toll booths, increase the speed at which the booth can process traffic, or both. Likewise, if enterprise network resources remain stagnant, then traffic delays will occur. Users will wait longer to get and process data.
BYOD and bandwidth
- Part one: How BYOD strains corporate network bandwidth
- Part two: Limiting mobile bandwidth consumption to improve network performance