>Elijah Savage wrote: >> >> I have been trying to follow this, and I still do not see why >> we should >> get away from the old Cisco switch courses that if you set both >> sides to >> 100 full duplex if they are capable you will be fine. I have >> not seen >> any situation where hard setting both sides caused problems (am >> I >> missing something?). Question I ask is why even fool with the >> unpredictable auto negotiate. > >Setting both sides manually to 100 full works (as long as you don't have Cat >3 cabling), but it's not a maintainable solution. > >Say you get laid off (heaven forbid) without a chance to document your >procedures. Your replacement, fresh out of the newer Cisco courses, has the >job of replacing a NIC in a workstation or server. She doesn't set the speed >and duplex manually, since there *should* be no need. > >The switch is set to manual. This means, as John has said, that it may not >participate in autonegotiation. Why should it? It knows what it should be >since you manually configured it. The behavior is undefined in the specs, >but that would be OK behavior and is something we see in the real world. > >The new NIC doesn't see any autonegotiation going on and decides that the >device at the other end must be so old that it doesn't support >autonegotiation and, in fact, if it's that old, it must be 10 half. The NIC >sets itself to 10 half. > >You have a mismatch. > >Priscilla
It's actually even worse than this! Let's say you currently have a 2924XL switch and all attached hosts are manually set to 100/Full on both the switch and the end device. If you replace the 2924XL with a 2950 using the EXACT same configuration, you might run into problems because the 2950 disables autonegotiation completely when you manually configure the speed, which might cause an end device to assume it's connected to a hub and downgrade its connection to 10/Half. So, with a 2924XL things might be running just fine with both sides manually configured, but if you upgrade to a 2950 you might end up with speed/duplex mismatches. I've seen this more times than I can count in the last six months. I'm not exaggerating when I say that at least two or three times a week we run into another device that is having problems, and about 97% of the time setting both sides to auto clears up the problem. John Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=65076&t=64931 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
