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Networking Problems

by Benjamin Anderson 4. January 2009 20:34

I’ve always known that there was a problem with the Auto Negotiations for my 1Gb network, but I’ve never looked into it much because there were a lot of other factors playing into the problem.  My newest desktop is an HP Elite m9180f, which has a Core 2 Quad Q6700 and 4GB of RAM, so it is plenty fast and it can really take a beating during development work.  But it has been the slowest device on my network, including the wireless and 100Mb devices.  It has a Broadcom 1Gb chipset, but while diagnosing the problem it ran faster at 100Mbps Full Duplex than it did at 1Gb.

Here were the issues that contributed to the slowness:

  • Vista’s network buffer and auto management.  In order to improve performance Vista will auto manage the communication buffer so that it can expand and shrink it as it sees fit.  I’ve disabled this completely and have seen drastic improvements.  The settings also disable several of the more advanced communications changes in Vista’s new network and IP stack, but my old network equip doesn’t support any of it anyways.  I also saw improvements at 100Mbps after disabling it as well.
  • Disable the wireless chipset on the desktop.  This model includes a 802.11n chipset, which works well, but Vista gets confused as to which network it should communicate with when both NICs are on the same network and subnet.  This might not be as big a deal now that I have the duplex issues resolved, but I haven’t tested it yet.
  • Removed an old Netgear 1Gb switch.  It was my first 1Gb switch, but I’ve had it for at least 5 or 6 years, and it isn’t working correctly.  The iMac won’t even communicate with it at any speed.  In order to remove the switch I had to rewire most of my network and move some of my equipment to another room in the house, but everything is running much faster now.
  • Part of the problem was covered up by bad Time Warner Cable service, which slowed down all of my systems when accessing the Internet.  This is still an issue a lot more than I’d like, but it isn’t related to this system.  It did how ever cover up the biggest internal networking issue.
  • Concurrent back ups.  I have two Home Servers, an older smaller one used for my business machines and a newer larger capacity one for my personal machines and Rebecca’s desktop.  The backups with running on top of each other, and were saturating the network since both machines are on a switch on the on the other side of the house connected with an up link to my main switch at my desk.  I also have other backup devices scattered out on the network that kicked off around midnight till 2:00AM and everything ended up running over the top of each other.  I’ve rearranged the backup scheduled to speed them all up some.


The issue was really only noticeable when transferring data from one of the NASs or from the Windows Home Server for my personal machines, but today it started impacting everything, including dropping my transfer rates to and from the internet to below 500kbps.  That makes working on a project over the VPN impossible.  I tried to watch some streams on Hulu, but it was so slow that the videos could never even buffer.

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Categories: troubleshooting


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About the author

Benjamin is a software developer in the DFW area.  He spends his free time playing video games, programming, doing graphics design and photography, and reading.

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