posted on December 26, 2008 22:14
During 2008 Verizon offered FIOS with 10 Mb download and 2 Mb upload in my neighborhood as an upgrade to DSL. Most of my neighbors thought that their new network connections would be at least 10 times faster. They were disappointed. This post is intended to explain the factors that are part of network performance to your home.
Performance over any network has to do with several factors - Latency and Bandwidth and the performance of the connectioning hardware and software at each endpoint.
Latency can be thought of as the time it takes for a request for a small amount data to make a round trip from the requesting computer to the source of the data and back. For example, from Seattle I click on a web page located in NYC and I start to get data back. This time for this is almost completely dependent on the round trip physical network distance between Seattle and NYC which is about 80% the speed of light. Using a satellite connection could make this distance about 50,000 miles per hop. The double-hop satellite delays to distant places you occasionally on TV are the same latency issue.
Since most web pages are small files, latency is the dominant component of what people see as performance of the web. Latency is the reason that Amazon, Microsoft and many other large companies use Content Delivery Networks to distribute their web pages physically to additional sites in Asia and Europe. Physical closer to the customer is faster because there is less latency!
Bandwidth can be thought of as the maximum amount of data that can be sent over a connection, using all available techniques to keep the data pipeline full. Bandwidth is the dominant component when transferring very large files.
Endpoint Network Performance - When I transfer a 1 GB backup of this web site from Omaha to Seattle, bandwidth is more important than latency. I had hoped that this was one area that FIOS would improve for me. The data center in Omaha where we house the systems that host Aging Safely’s web site don’t want to allow a few high bandwidth users to consume all of the network capacity thereby denying service to other customers. They limit the bandwidth that any single user can have to about 1 Mb. As a result I still only receive DSL-like speeds on these transfers. Downloading large kits from Microsoft is one of the few times I actually see the full FIOS performance. Businesses, such as Netflix, that depend on delivering large amounts of video data online to their customers are likely to have networks that that can give to 10 Mb performance. Hopefully other sites will increase their network bandwidth in the furure.
I must still make local software optimizations, even though I have a modern computer with a local gigabit network . Windows XP’s default TCP/IP interface settings don’t allow for high bandwidth performance. When Windows XP first shipped in 2001, today’s high bandwidth networks at home were not a consideration. One must optimize the Windows XP’s TCP/IP settings using a tool like TCP Optimizer before you will be able to see the performance better than DSL. Vista and Windows 7 are smart enough to set the TCP/IP settings automatically.
Many Speed-test sites don’t measure accurately at above 5 Mb for performance reasons at their sites. Initially Verizon installed a 5 Mb connection at my home. Rapid System speed testing tool, which I like, indicated that I was getting about 5 Mb. When Verizon upgraded me to 10 Mb, Rapid System’s tool still showed 5 Mb. I discovered that I had been upgraded when Netmeter showed that I was actually downloading data from Microsoft a close to 10 Mb.
I hope that this post helps you understand the issues with high speed network performance at your home.