Multiple Copies of same frame using RSPAN

Unanswered Question
Jan 30th, 2007

Hi,

I am monitoring tx/rx on two ports on two separate switches. I am reflecting to a remote vlan, where I have my ethereal cable connected.

My trace shows 3 copies of every packet. Is there any way to eliminate this problem, or is it simply the best I can get when I want to use RSPAN?

Thanks,

Steve

I have this problem too.
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lujohnso Tue, 01/30/2007 - 19:13

How many links are carrying the RSPAN VLAN? If you are truly only spanning these two ports and not an entire VLAN, that doesn't quite sound right. Are these two ports in the path of the packets that you are spanning? Are you certain these are the same packets? Look at the source/destination MAC addresses, are they all the exact same?

svick2771 Wed, 01/31/2007 - 07:55

Hi,

They are copies of the same packets, because they are rtp packets, and the ssrc and timestamps are the same.

I have one router with 5 switches. It's a basic stub. I am not using redundant links between each of the switches, so there are no loops in my network.

I might have it configured wrong, so let me ask a couple questions.

1. Do I need to create a sub int on the router, or do I simply create the VLAN on my VTP Server?

2. Do the ports I am reflecting from need to exist in the remote span vlan?

3. Does the port to which I am reflecting need to be in that rpsan vlan too?

In terms of my configuration, I am only monitoring 2 ports, not vlans. Those ports exist on two different switches, and the reflected port is on a 3rd switch.

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