No, that's not at all what I was referring to. I'm speaking of the behavior of switch interfaces when they're set to AUTO. Nortel switches (at least the ones that we used) and some older Cisco switches like the 2924XL seemed to behave like Option #1 below, while the 2950 behaves like Option #2.
If both the switch and the device are using Option #1 you'll be fine. If you then upgrade to a Catalyst 2950 that uses Option #2, you'll have all sorts of issues that need to be resolved. We've had a mixture of 2924XL and Bay 303/310 switches at our branchse for quite a while with no issues. When we started replacing the Bays with Catalyst 2950s we started having all sorts of problems, and it took quite a bit of research into FastEthernet NWAY/Autonegotiation to determine the problem. Just a forewarning. :-) >>> Scott Roberts 3/10/03 12:12:48 PM >>> if I understand what you're saying, I think its always been like that, cisco hasn't changed it. you're refering to the fact that the IOS switch don't let you change the speed? I think thats strange also, the set based switch can allow you to change speed, but after the IOS "upgrading" of switches they don't allow you to change a 10/100 at the switch, but rather require you to configure the desktop to 10 or 100 speed manually. I suppose the idea is that everyone should be using autonegotiation according to cisco. scott ""John Neiberger"" wrote in message news:[EMAIL PROTECTED] > I wanted to mention that we've been in the process of upgrading our > switches, as well, and I discovered that since we've started using the new > Cisco switches we've been having all sorts of problems getting the speed and > duplex settings set correctly. > > We've discovered that if you have relatively new NICs with updated drivers, > set both sides to AUTO. Never, ever, set only one side to AUTO. I'd also > avoid manually configuring the speed and duplex unless you have to do so to > fix a specific problem. Here's why: > > There is no standardized behavior for 100BaseTX when you manually configure > settings! The only setting mentioned in the specification is AUTO; the > behavior of the NIC with any other setting is up to the vendor and not > everyone handles it the same way. Cisco appears to have changed the way > they handle it, which is the cause of a lot of our problems. > > If you hard-set the speed and duplex there are two ways to handle this: > > 1. Use the configured settings and still participate in autonegotiation > only offering the configured settings. > > 2. Use the configured settings and do not participate in autonegotiation > > Cisco's new switches seem to use option #2, while a great number of our end > devices use option #1. Why is this a problem? Here's what happens when you > connection an option #1 device to an option #2 device: > > #1 participates in autonegotiation, only offer the configured settings. > #2 does not participate in autonegotiation at all and will forcefully use > the configured settings. > #1, seeing that there's nothing on the other side using auto assumes it is > connected to a HUB, and just might set itself to 10/Half regardless of the > manually configured settings! > > As you can guess, this is bad mojo. The moral of the story is that you > should try to start using AUTO on BOTH sides if you're using newer Cisco > switches, in particular the 2950 series. In some cases this won't work and > you'll have to resort to manual settings. > > HTH, > John > > > >>> Priscilla Oppenheimer 3/10/03 10:58:56 AM >>> > Mike Momb wrote: > > > > To all, > > > > We recently replaced our Nortel switches and routers with Cisco > > 2980 switches and 6509 routers. We have two buildings, 10 > > floors each and a router in each building. We have a > > combination of NT and Novell servers. After replacing all > > this equipment, we have noticed that when we access files on > > the NT servers, the speed is acceptable. When we access files > > on the Novell servers, it is very very slow. Could the > > switches or routers be configured incorrectly for IPX. Is > > there something that we can change. On Cisco's web page it > > mentioned something about enabling ipx > > broadcast-fastswitching. Any input or comments would be > > appreciated. > > I doubt that ipx broadcast-fastswitching will help you unless you are using > an ipx helper-address. With ipx helper-address (just like ip helper-address) > you can tell a router to forward a broadcast, which it normally doesn't do. > This would be useful for some rare IPX application that sent broadcasts that > needed to reach the other side of the router. In typical IPX networks, > there's no such need. When there is a need, you can speed it up with the ipx > broadcast-fastswitching command. > > You titled your message "10 half or 100 full." I think this was a Freudian > slip. I bet your problem is related to a full-duplex mismatch. Perhaps the > NICs in the NT servers negotiated correctly but the NICs in the Novell > servers did not and you have a mismatch. > > With a mismatch, the full duplex side will send whenever it wants. The half > duplex will get upset if it sees the other side sending while it is also > sending and will backoff and retransmist, leaving behind a CRC-errored runt. > That side will reports a collision. The other side will report runts and CRC > errors. > > So, look for lots of Ethernet errors when you do a show int or show port. > > Also feel free to send us the output of various show commands and your > router config. There are some IPX gurus on this list. > > _______________________________ > > Priscilla Oppenheimer > www.troubleshootingnetworks.com > www.priscilla.com > > > > > > > thanks > > Mike Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=64948&t=64931 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
