Hi Kevin, Sounds like your facing a well known problem in a switched network in my opinion. I guess your clients where previous on a shared network ? So 9/10 there was no STP running on every port. But in a switched network all port's will run STP. The problem that you will get on switched networks is the following. Window PC's are seeing that there NIC is up and start sending DHCP requests. The port on the switch is unluckily still in the listen / learning phase. So all these DHCP request are just getting dropped by the switch port. Windows PC just thinks that he can't reach the DHCP server. A simple release / renew will fix the problem indeed. The port will be in forwarding state by now. A lot of user will try to reload their pc's but will be facing the same issue again. (Port goes down on the switch)
I just hope that you are aware of a feature called spanning-tree portfast. This will make the port on the switch to skip the listen / learning state and go immediately to forwarding. This should be enabled on all user cats anyway to avoid TCN msg. (could cause unnecessary floodings) On the catalyst there is even a build in command that will optimize the user ports further. "Set port host mod/port" That will even turn trunking and channeling of. SO it will even minimize the total time for a packet can be forwarded. Regards Joachim -----Original Message----- From: Kevin Cullimore [mailto:[EMAIL PROTECTED]] Sent: 28 September 2002 20:46 To: [EMAIL PROTECTED] Subject: Re: OT: Serves Me Right - DHCP problem [7:54402] Your customer would probably be gravely offended and unbelieving at the prospect that most major changes in digital computing connectivity involve a trade-off of some kind, but that doesn't render it any less accurate. In this case, since the trade-off is between exposure to non-unicast traffic and level of interactive involvement with the address procural process, why not shrink the relevant timers? Would they notice the extra traffic? If they're not happy with either scenario, then both the issue & its resolution catapult way above the OSI layers that fall within the IS manufacturer's purview, usually leading to a rather ungraceful resolution. I've found that opponents of major redesigns will leverage the reality that many types of changes do NOT result in situations featuring only benefits and no drawbacks to fight or impede the cutover as vociferously as possible, forcing an appeal to the economic considerations that motivated the project in order to squelch the dissensiion. ----- Original Message ----- From: "Chuck's Long Road" To: Sent: 28 September 2002 1:28 pm Subject: Re: OT: Serves Me Right - DHCP problem [7:54402] > I see I should have made this one a "Friday Folly" :-> > > In a Big Flat Bridged Network, a mobile user unplugs the laptop at one > office, drives over to the next office, plugs back in, and no further action > is required. The Windoze PC has retained it's IP address, and the network > doesn't care about location, because it is one big flat network. > > However, in the brand new ATM based AVVID ready routed network, said mobile > user is now in a different segment in each location. With Windoze, you have > to manually intervene. Sometimes you have to release the IP address, reload > the computer, and then get your new DHCP assignment. Users don't like this. > After all, now they have to do something, whereas before they did not. Never > mind the higher speed, the failover capability of the routers, the new 100 > mbs switches rather than 10mbs. They have to take an extra step or two in > order to log in. > > This is normal behaviour for Windoze machines, and maybe for DHCP clients in > general. I have had to do this release / renew for years. > > But to the customer, who is pretty naive in terms of networking, there is a > "problem" that was caused by the new routers. To the users, there is a > problem that never existed before. > > Like I said, serves me right. You give a customer a great new network, and > you break something so rudimentary that it never would have occurred > otherwise. :-> > > -- > > www.chuckslongroad.info > like my web site? > take the survey! > > > > ""Priscilla Oppenheimer"" wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Spare us the mystery and tell us what you're getting at. :-) Did you > forget > > to tell the DHCP server to provide the correct default gateway address to > > the PCs? That's my guess, since you say everything else like helper > > addresses, etc. is configured correctly. Just a late-night theory, > waiting > > for Jay Leno to come on..... > > > > Thanks, > > > > Priscilla > > > > Chuck's Long Road wrote: > > > > > > The AVVID solution I sold a few months ago is gong through > > > implementation. > > > This project has been problematic for a lot of reasons, so it > > > is not unusual > > > for a round of e-mails from the customer complaining about one > > > thing or > > > another. > > > > > > Today was a good one, however. Shows to go you have to ask > > > things you > > > normally wouldn't think about. > > > > > > DHCP - no big deal. Works fine. All of us have probably used it > > > or > > > configured it. All of us probably have experience with running > > > several small > > > sites off a single DHCP server at a central site. > > > > > > So why is the customer complaining about DHCP not working, and > > > it's because > > > our routers are screwed up and Microsoft told them that they > > > would have to > > > change their network addressing to a single class B rather than > > > subnets of > > > /16 space, the way I designed it? > > > > > > The routers are configured correctly. The network is designed > > > correctly - no > > > overlapping subnets. IP helpering is configured correctly. > > > > > > Problem occurs with several users, different NIC's, either > > > Win2K or WinXP. > > > No one common factor. Worked just fine before we put the new > > > routers in. > > > > > > Recognizing that Microsoft is full of C**P and their TCP stack > > > is S**T, > > > still, why the problem. > > > > > > Gee, what happens to DHCP when you go from a single flat > > > bridged network to > > > a segmented routed network? Especially to mobile users, who > > > travel from site > > > to site for various reasons on a regular basis? > > > > > > Serves me right > > > > > > Chuck > > > > > > -- > > > > > > www.chuckslongroad.info > > > like my web site? > > > take the survey! Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=54442&t=54402 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
