# Understanding RMON Statistics

I am really, really confused understanding RMON statistics. As a test in hopes to figure it out I copied a huge file from my server to my computer and tham took a look at the RMON statistics:

Computer Port      TX=15,348,122     RX=2,448,417

Server Port           TX=2,449,684      RX=15,245,929

I have to be looking at it wrong. This huge file went from the server to the computer but the computer (port) sent a whole lot more then it reveived. Can someone give me a little better understanding of what I am looking at when I look at the RMON statistics?

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Commented:
I think you have it. The sent and received in the RMON stats, which are from the switch, is relative to the switch port not the device. So sent by the port is received by the device and sent by the device is received by the port.

I know it's confusing because in your mind you want to look at it as sent and received by the server.
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Commented:
RMON statistics are just counters collected on the switch and then sent to the management application for each time period.
Your counters are showing the information's direction relative to the switch port not the server's nic which is the reverse.
So you are transmitting out the computer's switch port at the high rate that was received in the server's port.
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Author Commented:
Thanks Rick. I started out yesterday looking at it from the switch port standpoint and that is where the confusion started. Take the above number. I copied a larger file from the server to my computer. The Server switch port received 15,245,929 (which is close to the file size) but onlt sent 2,449,684  and that is what is throwing me. I figured is the server port would have received 15,000,000 (the file from the server) that it would have sent 15,000,000 getting it to the workstation. But it only sent 2,000,000. Even looking at it from the switch port standpoint I and still looking at something wrong.
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Commented:
I think the numbers are looking correct.
Look at the 15MB sent by the server this way:

server NIC TX ----RX server port---switch---computer port TX----RX NIC computer
15MB ----15MB----------------------------------------15MB----15MB

The 2mb sent by the PC is what is received by the server but it too is reversed relative to the switch port at each end.
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Author Commented:
I new I was going to have a problem explaining my confustion :) I am looking at something backward. If the server port recieved RX 15,000,000 (from the server) how come the server port transmit TX is only 2,000,000? To me that would imply that there are still 13,000,000 sitting in the server port waiting to be transmitted. I know I am missing something simple. I just can't put my finger on it...
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Author Commented:
Maybe a light bulb has come on and I have over killed the thought process. Are the numbers you see in the statistics simple what was sent and recieved from the device attached to that port?

Take the server port. It has sent 2,000,000 to the server and received 15,0000 from the server

The computer port has sent 15,000,000 to the computer and received 2,000,000 from the computer

So the RMON statistics are what was sent to/received from the device attached to that port?
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Author Commented:
Thanks Rick. I kind of tested it. I sent a bunch of stuff to a network printer and then looked at the RMON on the printer's switch port. The TX was high and the RX was almost zero. You have supplied the missing link...
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