What switch and OS? I'm wondering if Cisco hasn't changed some thing since
you ran into this. I think on a 6500 install we had it at about 10 seconds
after power-on that a PC would be up (tcp/ip stack loaded) and successfully
requesting a DHCP'd address (and not have any problems once portfast was
set).
--
Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+
List email: [EMAIL PROTECTED]
Homepage: http://jason.artoo.net/
wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> Believe it or not it's true! We did some test/research on it and we had
to
> modify some of our login processes to allow the switch to go the STP
> process for login, it appeared we were requesting to quickly for the
switch.
>
>
> -----Original Message-----
> From: Priscilla Oppenheimer [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, May 02, 2001 1:42 PM
> To: [EMAIL PROTECTED]
> Subject: Re: Spanning Tree Protocol [7:2564]
>
>
> If it really takes 15-30 seconds for a switch to forward even when
portfast
> is enabled, I can see why AppleTalk nodes would hate this. An AppleTalk
> node sends messages right away to make sure its own address is unique, and
> to find the nearest router, and verify the network number(s) and zone
> name(s) for its local network. If the switch isn't forwarding these
frames,
> the Mac will think it's on a non-routed single network, when it probably
> isn't. Worst of all, it might end up with the same address as some other
> AppleTalk device.
>
> However...... I find it hard to believe that even with portfast enabled a
> switch takes 15-30 seconds to forward traffic. Is that really true?
>
> Priscilla
>
> At 01:22 AM 5/2/01, Jim Gillen wrote:
> >I have had plenty of experience with this problem when I updated a token
> ring
> >network to a fully switched ethernet network.
> >
> >CISCO has a document on spanning tree and these types of problems.
> >
> >Enabling portfast still means that it takes 15-30sec for the port on a
> switch
> >to come up. If you workstation needs to attach to a server (as with the
> >Novell
> >Client) by sending GetNearestServer (or the like packets) and it needs a
> >reply
> >to attach during that 15 - 30 sec then it will fail to connect. There may
> be
> >other problems with the Mac's -???
> >
> >I would read the document on the CISCO site and then if that doesn't help
> let
> >us know what is the nature of the problem.
> >
> >
> >
> >
> >
> > >>> "Jason Roysdon" 2/05/01 13:30:21 >>>
> >This message has been scanned by MAILSweeper.
> >************************************************************
> >
> >The customer claims that even with portfast enabled the Macs won't
function
> >due to Spanning tree. Has anyone else heard any such rumors about this?
> My
> >guess, as you suggested, is that portfast would solve it, but supposedly
it
> >was tried before disabling spanning tree.
> >
> >--
> >Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+
> >List email: [EMAIL PROTECTED]
> >Homepage: http://jason.artoo.net/
> >
> >
> >
> >""Leigh Anne Chisholm"" wrote in message
> >[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> > > It's a symptom of the problem I wrote about earlier in this thread.
> When
> >a
> > > MAC becomes active on the network, the computer isn't able to
> communicate
> >for
> > > the first 50 seconds the port detects the end-system is active. The
> port
> > > begins in blocking mode, then transitions to listening, then learning.
> > > Finally, once STP determines that a looped topology hasn't occurred,
the
> >port
> > > is set to forwarding mode. This creates havoc with any end-system
that
> > > expects to receive over-the-network information within the first 50
> >seconds.
> > > IP, IPX, AppleTalk - all face the same issue.
> > >
> > > The simple solution isn't to kill Spanning Tree on all switches -
that's
> >the
> > > "I don't understand the problem so I'll do whatever works and create a
> >bigger
> > > problem" solution. The real solution is to enable portfast on all
> switch
> > > ports that have end-systems directly connected. The caveat to this is
> to
> > > ensure none of the end-systems are capable as acting as a bridge,
> >forwarding
> > > packets between LAN segments. Enabling portfast essentially disables
> > > Spanning
> > > Tree on a port - and Spanning Tree is used to ensure a loop-free
> >environment.
> > >
> > >
> > > -- Leigh Anne
> > >
> > > > -----Original Message-----
> > > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
> > > > Sent: April 30, 2001 7:15 PM
> > > > To: [EMAIL PROTECTED]
> > > > Subject: Re: Spanning Tree Protocol [7:2564]
> > > >
> > > >
> > > > Oh, speaking of AppleTalk. We've got a customer (not mine, but one
of
> >the
> > > > engineers working the account bounced this off me): They claim
their
> >new
> > > > Macs can't access the network if Spanning Tree is enabled.
Supposedly
> >this
> > > > has been verified by Apple and TAC (but we've never had a customer
lie
> >to
> > > > us, so that must be gospel, right. Heh, not). I don't know what
> >exactly
> > > > the details are, but basically it just doesn't function. The simple
> > > > solution is to kill spanning-tree on all the switches, but this is
at
> a
> > > > number of public schools, and I can't wait to hear about a kid
> bringing
> >in
> > > > his Linksys 8 port 10/100 switch and melting their network.
> > > >
> > > > Anyone else hear such rumors?
> > > >
> > > > --
> > > > Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+
> > > > List email: [EMAIL PROTECTED]
> > > > Homepage: http://jason.artoo.net/
> > > >
> > > >
> > > >
> > > > ""Priscilla Oppenheimer"" wrote in message
> > > > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> > > > > At 11:08 AM 4/30/01, Phil Barker wrote:
> > > > > >Strongly in favour,
> > > > > >
> > > > > >A similar problem occurs in an IPX environment.
> > > > > >Make sure all Servers/Clients are 'portfast' and
> > > > > >switch/switch disable 'portfast'.
> > > > >
> > > > > A similar problem happens with AppleTalk too. That's what we get
for
> > > > > expecting switches to replace hubs in a topology. ;-) They were
> >designed
> > > > as
> > > > > bridges and to talk to other bridges. Despite switches being the
> > > > > new-fangled thing (well, sort of new), a lot of their
functionality
> is
> > > > > vintage 1980s.
> > > > >
> > > > > Priscilla
> > > > >
> > > > >
> > > > > >Regards,
> > > > > >
> > > > > >Phil.
> > > > > >--- John Gotti wrote: > Hey
> > > > > >all...we are having a problem where workstations
> > > > > > > sporatically will not
> > > > > > > be able to obtain an IP address from our DHCP
> > > > > > > server. After about 4 minutes,
> > > > > > > you can perform a manual renew from WINIPCFG and you
> > > > > > > get your IP address.
> > > > > > > This has baffled me for quite some time and I have
> > > > > > > recently been told it is
> > > > > > > our Cisco 2924 Switch to blame. The story I was told
> > > > > > > is below. I welcome any
> > > > > > > comments for or against this opinion. Thank you for
> > > > > > > your time.
> > > > > > >
> > > > > > >
> > > > > > > "It appears the problem is connected to the
> > > > > > > spanning tree algorithm used
> > > > > > > by the CISCO switches. By default, ports on the
> > > > > > > switch block as they are
> > > > > > > initialised; during this phase the port is in its
> > > > > > > spanning tree algorithm
> > > > > > > learning and listening state - it is not
> > > > > > > forwarding. This is specifically
> > > > > > > aimed at ports that will be used to connect to other
> > > > > > > switches/routers in a
> > > > > > > stack. After a default time (4 mins?) they switch to
> > > > > > > the standard forwarding
> > > > > > > mode and everything seems normal, the problem is
> > > > > > > that you have missed all
> > > > > > > the important DHCP broadcast and acknowledgment from
> > > > > > > client to DHCP server
> > > > > > > during this period.
> > > > > > >
> > > > > > > You can change this default state by changing the
> > > > > > > PORT-FAST setting on
> > > > > > > each port. The port is then immediately in the
> > > > > > > FORWARDING mode as it is
> > > > > > > initialised. By default this setting is DISABLED,
> > > > > > > I have ENABLED all
> > > > > > > ports except the ports doing the linking to other
> > > > > > > switches"
> > > > > > >
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> > > > > ________________________
> > > > >
> > > > > Priscilla Oppenheimer
> > > > > http://www.priscilla.com
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> ________________________
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> Priscilla Oppenheimer
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