topic Re: Excessive Broadcasts in Switches, Hubs, and Modems

Excessive Broadcasts

Alberto Frosi — Thu, 25 Jan 2007 06:18:33 GMT

Hi,
There's this error too in the same swicth!My question is, what can i do for reduce the broadcast on this switch?
Where can i operate for solving this problem? In the switch or in the instruments (PC, client or anything else)?
Thanks a lot.
Best regards
Alberto

Re: Excessive Broadcasts

Matt Hobbs — Thu, 25 Jan 2007 07:20:06 GMT

The switch only reports what it sees, but you may be able to reduce the sensitivity of the switch logging these events with the 'fault finder' command. Set it to the lowest sensitivity. You can do this through the CLI or the web interface.

Re: Excessive Broadcasts

Alberto Frosi — Thu, 25 Jan 2007 08:00:13 GMT

I've posted here my first problem:
Hi all
Last night a hp switch 4108 for more port report
this error: Excessive CRC/Alignment Errors on port XX.In the same switch are connected more instrument HPLC and 1 server.
The server at 2.11AM has last the connection with all instruments and with another server connected in another switch.This error are appeared for any port too in the same switch.
What can i check for resolve the problem?
Till 15 January what this problem on the switch apperead!
Thanks a lot in advance.
Regards...
Alberto Frosi

Re: Excessive Broadcasts

Lei.Ma — Thu, 25 Jan 2007 20:58:54 GMT

You can disable the CDP RUN , interface all , disable the LACP, no flowcontrol . then show logging again.

when you see the CRC error, other option you need check the cable or the computer's NIC.

Re: Excessive Broadcasts

Ron Kinner — Fri, 26 Jan 2007 11:19:14 GMT

CDC errors are often caused by manually setting a port to 100 FULL then leaving the others at AutoNegotiate. AutoNegotiate is only allowed to work correctly if both ends are set to AutoNegotiate. If you set one end to Full the other side will not be able to AutoNegotiate to FULL and will be stuck at HALF. (It's in the AutoNegotiate specs that way. I guess they were afraid of it making a mistake back when most people just had hubs)

The side set to FULL will show high CRC errors. The AutoNegotiate HALF side will show a large number of collisions. The CRC errors come about because the Half side sees incoming traffic when it is transmitting and thinks it's a collision so it stops sending immediately which results in an unfinished packet reaching the FULL side. This unfinished packet is interpreted by the FULL side as a CRC error.

Ron