topic Re: problems with a HP4108 GL switch in Switches, Hubs, and Modems

problems with a HP4108 GL switch

Stern_1 — Mon, 14 Oct 2002 13:28:22 GMT

Hello,

I have some problems with one of my HP4108 switch. It seems that it work as a hub !!! unicats traffic that i'm not the destination are sending to my network card !
I don't understand.
Can you help me ? is it possible to turn a HP4108 switch into a hub operating mode ?
I have the last firmware.

Re: problems with a HP4108 GL switch

Ron Kinner — Mon, 14 Oct 2002 19:44:40 GMT

Most switches have the ability to select one port as a monitor port and to send copies of traffic on other ports to the monitor port. That would make it appear that it was acting as a hub but I'm not sure the port would be two way. Could be you could only listen.

Some switches let you statically assign a MAC to a port. The MAC stays assigned to the port after the PC has been removed. Could be you are seeing something like that but the extra traffic would be limited to only certain MACs.

If it thought your port were a trunk it might try to send all kinds of stuff to you.

Finally and most likely, if the switch receives a message for a MAC address and it doesn't know where the MAC is I presume it would act like a bridge and flood the message out every port to see if it would get a response. This could happen if the MAC table on the switch expires before the ARP table on a PC or router or if a static ARP table entry has been added to the arp table of a pc or router. Assuming something responds to the flood you shouldn't see any more traffic to that MAC until the table expires again.

What are you using to monitor the traffic with? Can you move to a different port to see if it has any effect?

Ron

Re: problems with a HP4108 GL switch

ASSIST — Wed, 06 Nov 2002 09:41:31 GMT

Hi!
I'm experiencing the same problem with a 4108gl.
I have heard some ports of the switch with Sniffer Pro (NAI) and it happens in all the ports. The monitoring port is disabled.
Have you found a solution to the problem?
Thank you.

Re: problems with a HP4108 GL switch

Arimo Laine_2 — Tue, 19 Nov 2002 13:53:04 GMT

Hi.

Turning a switch to "hub mode" is not possible at all.

Is the device flooding all unicast traffic, or is this a question of some specific application, is all this traffic directed to same destination?

Arimo

Re: problems with a HP4108 GL switch

Romeo Chance — Thu, 05 Dec 2002 21:34:59 GMT

Hi,

I had the same problem (unicast flood)
on my Procurve 4000M switch.

After months of battling, i found that
changing the MAC-AGE time on the switch
from the default setting of 5mins to 30mins
solved the problem.

If you havent solved it, try that and
it should stop the unicast flood.

Romeo

Re: problems with a HP4108 GL switch

OLARU Dan — Thu, 13 Feb 2003 12:26:05 GMT

The october firmware was buggy. HP solved many issues in 16th December 2002 with G.07.21, which you can find at http://www.hp.com/rnd/software/switches.htm