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The network at my work has about 40 computers on it and a quite a few printers. When there are a lot of people working the network will be slow.
I can test the ping between my computer and the router and it will keep rising, sometimes to the point that it times out.
The router we are using is running Ubuntu on a atom processor and it has 4gb of ram.
When the network slows the process Ksoftirq
will be using most if not all of the processing power. I have found that Ksoftirq
is a process that handles irq requests. Also when the network slows down I have captured packets from the router and using tshark and looked at it using wireshark on my laptop. With the capture show a lot of packets with TCP Dup ACK and TCP Retransmissions. The destinations of the TCP Dup and TCP retransmissions are to most of the computers on the network but there are some that are far more than others.
What could this problem be caused by?
1Dup acks and retransmissions are a typical a sign of timeouts due to network congestion, but can mean other things. Network performance issues are not always as simple as looking at a pcap. What is your workflow like (ie, what type of data/applications, how much do you move across the network, how often are new connections made, do you use encryption anywhere)? And for setup, what protocol are you using? what is the link rate of the clients? what is the mtu on clients and router, how long are your cable runs, number of hops between clients? There is a lot more to clarify, but that is a start. – MaQleod – 2012-07-09T20:06:26.430
there doesn't seem like there is ever lot of bandwidth being used when i look at a iftop. Almost all of the traffic is though the web but there is a lot of traffic that we use a vpn with ipsec. – monkthemighty – 2012-07-09T21:56:55.630