On Mar 26, 2010, at 4:33 PM, Mark Foster wrote: > >> "Desktop" switches. You know, those 4 or 5 port Gigabit Ethernet >> switches. Apparently, many of them don't do any kind of STP at all. >> Recommendations on ones that do STP? > > If the network fabric you're on is important enough to cause you grief in the > event of a STP event, you shouldn't be fielding 'dumb' switches. > > Even the 'dumbest' switch I would ever place into user-space is fully > managable, layer 2 with VLAN's and STP support. That is, it's in a cabinet > or TC and fed by infrastructure cabling, and the only folks who can get at it > are the engineers and techs supporting the site. > > The other side of things is that if DHCP times out once during STP > negotiation, it rarely times out twice. Users whos machines are 'dynamically > connected' often enough to have STP related glitches in their DHCP grab > should know enough to hit 'repair' or run ipconfig /renew - or should be told > to reboot :-) > or reboot is problematic in many cases. Many systems drop link-state during reboot for a long-enough period that the bridge-port restarts its spanning tree process, making results across reboots consistently bad.
>> RSTP: is it any better than traditional STP in regards to "edge" ports >> and blocking before a loop gets out of hand? Or perhaps blocking for >> 5-10 seconds before going into Forwarding state, hopefully preventing >> loops before they happen but also allowing DHCP clients to get an >> address without timeouts? Recommendations on "Desktop" switches that >> do RSTP? > > There's plenty of desktop switches out there which are close to 'fully > featured' - but obviously there's money involved. If your uplink switch (at > the very least) supports STP then at least you can isolate the problem if the > switch itself can't handle, but I wouldn't recommend this. > With the additional advantage that the uplink switch link to the conference-room switch doesn't flap often enough to cause DHCP issues, but, will shut down the port if properly configured and the conference-room switch at least passes the BPDUs around the loop. Owen
