How much bandwidth is a Gigabit?
It's a lot more than your users can use...
By Michael Morris, Network World | Network World US | Published: 01:00, 12 September 2007
Do you understand how much bandwidth 1Gbit/s is? That's the question I often find myself asking users.
At our largest sites we have deployed Gigabit to the desktop - not because users need it, but because the price difference between 10/100/1000 and 10/100 cards in Cisco 6500s is small. Plus, there are better features in the 10/100/1000 blades than in the older 10/100 cards. So, might as well get the Gig blades.
Now, that doesn't mean users always get Gigabit. Some older PCs only support 100Mbit/s. However, most of our PCs and laptops have Gigabit NICs and users have become accustomed to seeing "Connected 1.0Gbit/s" when their PC boots up. And once users have Gigabit, they just assume they need it.
Last year we refreshed the network switches at our small sales offices. To save money we purchased Cisco 3750 10/100 switches. In the 3750 line there is a significant price difference between 10/100/1000 and just 10/100. Most of these field sites have sales people and connect to the datacentre over two 3Mbit/s WAN circuits. 3Mbit/s!
But the outcry when these users lost their Gig ports was intense. "How can I work with only 100Mbit/s?" "There's no way I can get my testing done without Gig." It was unreal.
Then it happened again over the last few weeks. As I mentioned above, our largest sites have been outfitted with 10/100/1000 for a while and users have come to expect their PC connected at 1Gbit/s. Then, over the last few weeks, we started deploying Cisco IP phones with only 10/100 ports. User PCs connect to the phone which connects to the network. Here comes the outrage again: "My team cannot support this change. Deploy new ports to our cubes so we can have Gig again." "This is going to impact our ability to support customers, my testing will slow down." "IT just doesn't understand our needs."
After several minutes of trying to explain to no avail to users they don't need 1Gbit/s since their network traffic patterns are not intense or sustained enough; or trying to explain there are no PCs that could even push 1Gbit/s; or explaining the study we did a few months ago that showed the highest user port averaging around 40Mbit/s I found myself asking them "Do you understand how much bandwidth 1Gbit/s is? You don't need it. 100Mbit/s is fine! In fact, 10Mbit/s would probably be OK."
Yes, there are definitely servers, databases, and network storage in a datacentre that can fill and benefit from 1Gbit/s ports, but not users. Any traffic over WAN links is going to be limited by lower WAN bandwidth and effect delay has on TCP. So, unless you're sitting on the same LAN as the datacentre with a home-built, water-cooled super-PC running your own compiled version of Linux......you don't need a Gig port!