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ITGround >> Cisco Gig Ethernet Throughput Question


5/7/10 12:34 PM
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JBALL
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I have a Cisco 3750G switch. Ive been running some throughput tests using a small program called netspeed. I send a gig worth of data from a workstation to a server. It calculates how quickly the traffic is sent over the wire. The best Im getting over the Gig switch is 307.67 Mbps. 

Can anyone speak to what speeds I should expect out of a Gig switch? I'm plugging directly into the switch using a cat 6 cable.

Thanks!

JBall
5/7/10 5:40 PM
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big_slacker
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Any layer 3 or process switched stuff running on the switch?
5/7/10 5:58 PM
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tycoon
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What is the bus speed of the storage?

http://en.wikipedia.org/wiki/Serial_ATA#Comparisons_with_other_interfaces


5/9/10 10:59 PM
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JBALL
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big_slacker - Any layer 3 or process switched stuff running on the switch?
Its a pretty basic config. When I get into the office I'll try to post some of it. 

In terms the bus speed of the storage, the test Im running is a network speed test. Its not copying an actual file but sending a whole shit load of packets over the wire. They are 15k SAS drives though.
 
5/15/10 2:19 AM
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Bryan Reese
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Not familiar with how well that test would saturate the wire. I'm familiar with a single host on a benchmark like this going to another single host not causing the network to be saturated. Do you have more hosts you can plug in? Run multiple servers to receive the data on one host, and then run 2-4 other hosts going to those servers.

iperf

If the test you are using can not do that, try out something like iperf. There are a lot of variables that go into data transmission such as the switch, NIC, data loss at any point (bad or questionable cable), and the OS and drivers you are using. Are you using offloading on the NIC?

Also, I believe the 3750 is a blocking switch. Just an FYI, but you won't get all ports running at line rate. Cisco is pretty bad for price performance.
5/17/10 5:16 PM
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StephenL
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where are you measuring the speed?

stephen

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