cisco vs. dell switch on fedora

Les Mikesell les at
Fri Jan 7 17:41:56 UTC 2005

On Fri, 2005-01-07 at 09:20, Paul Stewart wrote:
> Use *real* switches..;)  Cisco all the way...

Ummm, have you priced Cisco gig-capable ports compared to Dell...

> I *believe* that Dell gets their switches from 3com but could be 
> mistaken... if that's true it would explain more... we rip 3com's out of 
> production all the time to replace with Cisco...:)

No, it has to be SMC - the specs are identical.

> > i am having a heck of a time getting a dell 5324 switch to dhcp 
> > directly to a couple linux boxes i have hung off it.
> >
> > enabling portfast on the cisco switches instantly fixed this problem, 
> > so i was suprised to see no change on the dell 5324. it's like i 
> > changed nothing at all.

Just guessing: you probably have Ciscos on the same LAN and they
are refusing to use the Rapid Spanning tree standard with
other vendors, preferring to first attempt their proprietary

> > i have also disabled STP on the ports in question, but it still takes 
> > 1-7 seconds or more for the link to come up. this conflicts with a 5 
> > second timeout in the network scripts.

You really don't want to (and maybe can't) disable spanning tree
completely on a switch.  It is what keeps the network from melting
when someone accidentally - or intentionally - makes a loop among
the switches.  The Cisco portfast setting just makes it forward
packets while making the decision, which is still a little dangereous.

> > for now we have upped the timeout to 15 seconds in the network scripts 
> > while we hunt for a real solution.

Here is a link to a pdf describing how to make the Ciscos cooperate.
I'd think it would make sense for a dhcp client to check for
link before sending anything, but that's just me...

  Les Mikesell
   les at

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