Date: Sun, 15 Dec 2002 19:21:46 -0600 From: Dan Nelson <dnelson@allantgroup.com> To: Scott Robbins <scottro@nyc.rr.com> Cc: "Greg 'groggy' Lehey" <grog@FreeBSD.ORG>, FreeBSD-questions@FreeBSD.ORG Subject: Re: Hubs and switches (was: uninformed qstn...) Message-ID: <20021216012146.GC8563@dan.emsphone.com> In-Reply-To: <20021214060454.GA2291@scottro11.homeunix.net> References: <20021213060718.GA8054@tao.thought.org> <20021214034131.GH503@wantadilla.lemis.com> <20021213214850.D9342@seekingfire.com> <20021214040557.GA1797@scottro11.homeunix.net> <20021214054534.GK503@wantadilla.lemis.com> <20021214060454.GA2291@scottro11.homeunix.net>
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In the last episode (Dec 14), Scott Robbins said: > On Sat, Dec 14, 2002 at 04:15:34PM +1030, Greg 'groggy' Lehey wrote: > > On Friday, 13 December 2002 at 23:05:57 -0500, Scott Robbins wrote: > > > ... is that if one moves a computer from one location to another, > > > the switch seems to take its time flushing its tables and the box > > > won't immediately be able to get an address. It's only happened > > > once or twice with a VERY cheap Linksys (again, the switch is > > > probably 1-2 years old, and this problem might be fixed by now). > > > > This is probably a feature, not a bug. It's part of the spanning > > tree algorithm used to detect and avoid link-level routing loops. > > My expensive Cisco switch has the same feature, but I found > > somebody with enough Cisco-foo to turn it off. Check the > > documentation of your switch. > > Thank you, I'm glad you told me that. We're going to be moving some > machines around after the new year, and had thought that with the > higher priced switches we've been getting, that wouldn't be an issue. Remember that all these low-priced switches are unmanaged, which means that they come with a basic feature set that cannot be changed (you can't lock a port at a particular speed, enable/disable spanning-tree, etc). Part of the price of those expensive switches is their ability to be configured. Some Cisco switches can take up to 60 seconds to forward packets in a newly-activated port, because of all the features available on high-end hardware that has to be tested for. You can drop the activation time down to 2-6 seconds by telling the switch that a plain PC is on the other end. http://www.cisco.com/warp/public/473/12.html -- Dan Nelson dnelson@allantgroup.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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