Thanks for the testing! I have bad news for you. ;-) Three or 4 seconds is
a lot of time.
An AppleTalk device sends its AARP frame to see if its address is unique 10
times, with only 1/5 of a second between tries. Then it sends a
ZIPGetNetInfo. It tries that 3 times, I think with the same timeout. This
could happen before the switch is forwarding, even with portfast enabled it
seems. (These timeout values may be dated. I haven't looked at AppleTalk in
a while! But I bet it's still really fast, perhaps even faster on a G4? ;-)
My guess is that IPX and DHCP are really fast too. ARGH.
Priscilla
At 03:15 PM 5/2/01, Jason Roysdon wrote:
>I wonder what switch and software version you were running at the time? I'm
>trying this on a Catalyst 3524 XL Inline Power running 12.0(5.2)XU (I
>haven't upgraded it, so that's whatever it shipped with).
>
>I did a number of tests (but not enough samples to make it 100% accurate on
>the timing, but a general idea +/- 2 seconds). The digits "00:16:47," are
>time since boot, while the dated timestamps are accurate GMT. For each of
>my tests, I would attempt to physically plug in the patch cable at :00
>seconds based on the clock on my laptop, and both the laptop and switch are
>accurate from ntp (the log is not timestamped at :00 seconds, but just for
>your reference).
>
>The first with the port in the "out of the box" state with it left at
>defaults:
>00:16:54: ST: FastEthernet0/6 vlan 1 -> listening
>May 2 11:33:02.985 PDT: %LINK-3-UPDOWN: Interface FastEthernet0/6, changed
>state to up
>May 2 11:33:03.986 PDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface
>FastEthernet0/6,
>changed state to up
>00:17:09: ST: FastEthernet0/6 vlan 1 -> learning
>00:17:24: ST: sent Topology Change Notice on Port Group 1 vlan 1
>00:17:24: ST: FastEthernet0/6 vlan 1 -> forwarding
>! 32 seconds
>
>At 32 seconds I had ping replies at my desktop (using a static address, as
>DHCP wouldn't be accurate to see how fast it comes up).
>
>Next, I wanted to see if the inline power slowed bringing the power up. It
>doesn't appear to (of course, thinking about it, the only time it applies
>power is if it sees a certain loop/load between a pair of wires, the details
>I don't recall):
>
>Cat3524(config-if)#power inline never
>00:18:54: ST: FastEthernet0/6 vlan 1 -> listening
>May 2 11:35:02.497 PDT: %LINK-3-UPDOWN: Interface FastEthernet0/6, changed
>state to up
>May 2 11:35:03.498 PDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface
>FastEthernet0/6,
>changed state to up
>00:19:09: ST: FastEthernet0/6 vlan 1 -> learning
>00:19:24: ST: sent Topology Change Notice on Port Group 1 vlan 1
>00:19:24: ST: FastEthernet0/6 vlan 1 -> forwarding
>!32 seconds
>
>Again, 32 seconds with spanning tree left to the defaults. 30 seconds as
>far as the switch was concerned.
>
>Now lets enable portfast:
>
>Cat3524(config-if)#span portfast
>00:20:54: ST: FastEthernet0/6 vlan 1 ->jump to forwarding from blocking
>May 2 11:37:02.483 PDT: %LINK-3-UPDOWN: Interface FastEthernet0/6, changed
>state to up
>May 2 11:37:03.485 PDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface
>FastEthernet0/6,
>changed state to up
>! 3 seconds
>
>In 3 seconds my PC was pinging with portfast set.
>
>My final test, I wanted to see if locking to speed and duplex would increase
>the time at all:
>
>interface FastEthernet0/6
> duplex full
> speed 100
> power inline never
> spanning-tree portfast
>
>Cat3524#
>00:22:54: ST: FastEthernet0/6 vlan 1 ->jump to forwarding from blocking
>May 2 11:39:03.165 PDT: %LINK-3-UPDOWN: Interface FastEthernet0/6, changed
>state to up
>May 2 11:39:04.166 PDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface
>FastEthernet0/6,
>changed state to up
>May 2 11:39:06.622 PDT: %RTD-1-LINK_FLAP: FastEthernet0/6 link down/up 5
>times per minsh
>int
>
>Oops, the switch doesn't like all the flapping of my tests and left it in an
>down/up state (good thing to know though!).
>
>Ok, give it a moment without the cable connected and try again:
>
>Cat3524#
>00:26:54: ST: FastEthernet0/6 vlan 1 ->jump to forwarding from blocking
>May 2 11:43:03.200 PDT: %LINK-3-UPDOWN: Interface FastEthernet0/6, changed
>state to up
>May 2 11:43:04.201 PDT: %LINEPROTO-5-UPDOWN: Line protocol on Interface
>FastEthernet0/6,
>changed state to up
>!4 seconds
>
>I think this time I was a little slow getting the cable in, but basically
>the same results, 3-4 seconds and the port is up and pinging from my
>connected laptop. That shouldn't be a problem for any network devices, I
>wouldn't think. The only way I could see it affecting is if during boot the
>NIC is not activated until the drivers load, and then within 1-2 seconds the
>protocol stack gets access to the NIC before the switch takes the port
>up/up, but I don't think this would be any different with or without
>spanning-tree enabled.
>
>
>--
>Jason Roysdon, CCNP+Security/CCDP, MCSE, CNA, Network+, A+
>List email: [EMAIL PROTECTED]
>Homepage: http://jason.artoo.net/
>
>
>
>""Jim Gillen"" wrote in message
>[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> > 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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http://www.priscilla.com
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