Chuck, you do like living dangerously, don't you?!! :)
Prof. Tom Lisa, CCAI
Community College of Southern Nevada
Cisco Regional Networking Academy
Chuck Larrieu wrote:
> The other way to solve the problem would be to delete AppleTalk and use
> native IP on your Mac's ;->
>
> ( can't wait for PO's response to this one! )
>
> chuck
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, May 02, 2001 1:39 PM
> To: [EMAIL PROTECTED]
> Subject: Re: Spanning Tree Protocol [7:2564]
>
> It took me 10 times to get the thing to allow me to create a new account
> (each time, it would time out when I hit Continue, and when I'd go back all
> the form would be blank). Anyway, from the Knowledgebase at
> http://www.apple.com/support/ it appears that portfast or tuning the
> spanning tree learning->forwarding time down would solve the problem
instead
> of just disabling spanning tree. Also, it appears to not affect TCP/IP
> services at all, only AppleTalk (which does it's little song-and-dance at
> boot to get a unique address):
>
> http://www.info.apple.com/kbnum/n30922
>
> TITLE
> Spanning Tree Protocol: AppleTalk Issues
> Article ID: 30922
> Created: 3/10/99
> Modified:3/22/01
>
> TOPIC
> When the Spanning Tree Protocol is enabled on an Ethernet bridge or switch
> port to which a Macintosh computer is directly connected the computer may
be
> unable to use AppleTalk services.
>
> Enable Fast Convergence
>
> Several switch manufacturers have extended the Spanning Tree Protocol to
> allow the convergence time to be reduced. One of the enhancements usually
> available is the ability to safely and quickly move the port from the
> blocked state (listening and learning) to the forwarding state. For
example,
> if the bridge detects a single device attached to a port it can quickly
> assume that no other bridges are attached to that port and move the port to
> the forwarding state almost immediately. Check the manufacturer's
> documentation for specific information on how to configure this option for
> your switch. For example, Cisco has an option called 'portfast' that can be
> enabled on most of their switches. For additional information on this
> feature, see: http://www.cisco.com/warp/public/473/12.html
>
> Tune the Forward Delay Timer
>
> The Forward Delay timer can be tuned down to the minimum value. This value
> can usually be tuned down to a few seconds, which would give the switch
> enough time to move to the forwarding state before the address allocation
> packets were sent by the computer. If you choose to use this solution you
> must set these timers in the root bridge. The root bridge is the bridge
that
> transmits these timer settings to all other designated bridges. Although
you
> can set these timers on any bridge only the root bridge can effect the
> overall environment.
>
> Products affected
>
> AppleTalk services
> Macintosh computers ranging from the PowerBook 3400 to the latest Power Mac
> G4 computers.
> Note: TCP/IP based services are not affected.
>
> Question: Why does this only affect later Macintosh computers?
>
> Answer: Later computers start up faster causing the packets used for
> AppleTalk address assignment to be sent while the port is still in the
> blocked state.
>
> Question: Is Apple planning to change the way AppleTalk addresses are
> allocated to fix the problem?
>
> Answer: Apple has no plans to change the algorithms used for AppleTalk
> address assignment.
>
> --
> Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+
> List email: [EMAIL PROTECTED]
> Homepage: http://jason.artoo.net/
>
> ""Hire, Ejay"" wrote in message
> [EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> > There is an Apple knowledgebase article about this issue.
> >
> > It is Doc#30922.
> >
> > Ejay Hire
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
> > Sent: Wednesday, May 02, 2001 2:01 PM
> > To: [EMAIL PROTECTED]
> > Subject: RE: Spanning Tree Protocol [7:2564]
> >
> >
> > 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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