SPAN over fiber

Unanswered Question
Mar 21st, 2007

I am trying to set up SPAN over fiber. I have the server that I want to do the monitoring for a switch port. I am trying to get the tx and rx of a port and send it to the server. Since the link i am monitoring is over fiber i connected the link from the destination port to the server with 2 tx's because all i want to do is get the traffic that the source port is collecting and i am using 2 tx's because with the link i am monitoring being a 1Gbps that means 1G tx 1G rx. I only have the 2 tx's hooked to a fiber nic's rx ports (it has 2 tx/rx). but i get no link. will just plugging in the the other connections on the cable to the tx ports on the nic solve this to get a actual link?

sorry this is so confusing. please ask if you need more clarification or more specific questions. thanks alot.

I have this problem too.
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MZydorczyk2 Thu, 03/22/2007 - 06:52

I put up a diagram if anyone to look at to help me solve my problem. Thanks.

nyr.hakeem-habeeb Thu, 03/22/2007 - 07:26


do you get a tx signal out each fiber core on the last patch panel before your monitor?

If not trace back along each pp to see where it broke; could be patch cords? or fiber cores?

Hoping to hear from you.


MZydorczyk2 Thu, 03/22/2007 - 07:41

Yes I am getting the light through the cable fine. Is it possible to do this though, that is, use one fiber cable and send 2 tx over it instead of 1 tx 1 rx? Would it still create a connection if the recieves are not plugged in even though both tx's are going to both rx's on the end point?

nyr.hakeem-habeeb Thu, 03/22/2007 - 08:02


In my opinion, since this is optics you should be able to read data of the fiber (i.e. monitor)

In this setup you have;

Switch Monitor

tx rx

rx tx (not connected)

tx rx

rx tx (not connected)


nyr.hakeem-habeeb Thu, 03/22/2007 - 09:25

This is the scenario that i believe should allow the monitor to pickup data. If this is'nt what you have :-)


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