Switches, Hubs, and Modems
Showing results for 
Search instead for 
Did you mean: 

Problems with Monitoring Port Settings

Adam Cavaliere
Occasional Contributor

Problems with Monitoring Port Settings

I have a network of ProCurve 4000M switches. On one of them I am setting up a Monitoring port.

So right now I am trying to monitor 4 servers and one other port.

2 of the 4 servers have multiple NICs on them.

If I only monitor one of the NICs on each server, so a total of 5 ports I do not have any dropped packets.
If I monitor more than one of the NICs attached to the same server I have two things happen.
First I have had a message pop up warning that monitoring multiple ports may cause the same broadcast messages appear on the monitoring port. Then when I am monitoring the port with a packet sniffer I get A LOT of dropped packets maybe about 38%.
Do you have any ideas as to why I am running into this problem? Is it something to do with Automatic Broadcast Control?

Any ideas on what I should try to solve this problem?
Les Ligetfalvy
Esteemed Contributor

Re: Problems with Monitoring Port Settings

What are you saying, that you can monitor five ports without drops as long as they are not trunked ports but if you monitor just two trunked ports you have drops?

Or do you get drops when you add trunk members to the other five you are monitoring?
Adam Cavaliere
Occasional Contributor

Re: Problems with Monitoring Port Settings

The ports that I am adding are not trunked. The servers are doing routing (sad, I know). So I am trying to watch each interface.

I get the drops when I add more than one interface per server. So all is fine with the 5 ports. But if I add another interface from one of the servers it gives me dropped packets (monitoring 6 ports).

I can add other ports and not have any problems, only when I start monitoring ones that are hooked up to the same machine do I get errors.
Ron Kinner
Honored Contributor

Re: Problems with Monitoring Port Settings

Any chance you are just getting more packets than one port can handle? How busy are the server connections?

I don't know if Automatic Broadcast Control is in effect on a Monitor port but it would be easy to turn it off and see if that made a difference.

Adam Cavaliere
Occasional Contributor

Re: Problems with Monitoring Port Settings

I was wondering the same thing about the port having way to much traffic going through it. Any way that you know of for me to tell that? I have watched the Java interface that is supposed to show how busy the network interfaces are. None seem to be pushing very high at all. Haven't seen them sustain more than 20% each - no one was even in when I was testing this and so network traffic would have been light too (we only have at most 500 machines).

Re: Problems with Monitoring Port Settings


Exactly *where* do you get drops?
Is it on the switch itself or on the device that is doing the monitoring?

Also, you say 20% load each. Is that the ports you are monitoring? 5x20%=100% so packetrate could be a problem.