I don't think we can stress enough how important the speed/duplex mismatch and autonegotiation problems are. If you are having a LAN problem, this is one of the first things you should consider. The interesting thing thing about duplex mismatch errors is that things can seem like they are working okay, but you notice problems once in a while.
Every day, probably hundreds of thousands of users and servers are experiencing less-than-optimal performance because of this kind of problem. Are some or all of your IP phones rebooting every once in a while? Even this could have something to do with a duplex mismatch problem somewhere between your IP phones and your Call Manager. One question I have for folks is is whether duplex mismatch errors between a switch and one device on a segment (network printer, PC, server, etc.) could substantially degrade performance on the switch so that other links would be impacted in a noticeable way. Tom Larus ""John Neiberger"" wrote in message news:[EMAIL PROTECTED] > Orlando Palomar Jr CCIE#11206 wrote: > > > > Well said, John. I guess we'll still be seeing a lot of these > > until they standardize auto-negotiation accross all vendors. > > And that's the funny thing. Autonegotiation *is* the standard! ;-) It's > when you don't use auto that you've strayed from the standard. However, I > still find about get auto to work right. Most of those I suspect bad cabling but it would > have been too difficult to fix at the time. > > Here's a tip that I've found helpful, even if things seem to be running > fairly well after you upgrade to a newer switch. From time to time, clear > the counters and wait a while, then check for alignment errors, late > collisions, and CRC errors. Any of those are a good sign that you might > have a speed and/or duplex mismatch. > > I've been using this technique to slowly fix the connections to some of our > servers. Quite often the servers will appear to be working just fine but > they still need to be fixed. Other times, our LAN group spends weeks of > intermittent troubleshooting trying to solve a problem and it never occurs > to them that it might be a speed/duplex issue. They're always looking for > application or OS problems and they sometimes don't think to ask me about it > until they've run out of ideas. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=66448&t=66402 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
