Hi,
Thanks all for your infos. I did a search through a appletalk website and I
found some thing strange information. The website is
http://til.info.apple.com/techinfo.nsf/artnum/n30922.
It says that when the spanning tree protocol is enabled on an switch port to
which a mac system is directly attached the system may be unable to use
appletalk services.
Issues observed range from no AppleTalk services, local (to this specific
network) AppleTalk services, degraded performance, and intermittent network
services.
If the Spanning Tree protocol is enabled on the port to which a Macintosh
system is attached packets necessary for AppleTalk address assignment and
network discovery can be dropped by the switch. This causes the Macintosh to
acquire invalid or incomplete network information resulting in the behavior
discussed above. Fortunately there are some things you can do to resolve the
issue.
But the website also says that the TCP/ip services are not effected.
Anyway, I tried disabling STP and kept all the ports to auto mode in the
switch, to the surprise all the mac sys started negotiating and they are
running at full duplex and 100 mbps now and their is no complaint from the
users from past 2 days.
I don't know whether the problem was really beacuse of STP or something
else, I could not any R&D as users are online now.
Thanks
imrna
>From: "Chuck Larrieu" <[EMAIL PROTECTED]>
>To: "Leigh Anne Chisholm" <[EMAIL PROTECTED]>, "imran obaidullah"
><[EMAIL PROTECTED]>, <[EMAIL PROTECTED]>
>Subject: RE: Network Troubleshooting
>Date: Fri, 2 Jun 2000 18:01:28 -0700
>
>Hope you don't mind me butting in here. These kinds of design questions and
>capacity planning issues continue to intrigue me, and I want to continue to
>broaden my perspective by examining the thought processes of others.
>Comments below:
>
>-----Original Message-----
>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of
>Leigh Anne Chisholm
>Sent: Thursday, June 01, 2000 12:11 PM
>To: imran obaidullah; [EMAIL PROTECTED]
>Subject: RE: Network Troubleshooting
>
>It honestly sounds as if your first floor switch is having difficulty
>moving
>data between its ports and the server.
>
>When you're deploying switches in what has traditionally been a shared
>environment, you must be careful to ensure that you haven't oversubscribed
>your uplinks (whether they be uplinks to servers, or between switches).
>Plugging 24 100 Mbps (half-duplex) connections into a switch with a 100
>Mbps
>(half-duplex) uplink spells disaster. The 100 Mbps uplink contends with a
>theoretical (24 x 100 Mbps) 2,400 Mbps capacity. Using the same analogy,
>but lowering the client data rate to 10 Mbps results in a theoretical 240
>Mbps throughput for the 100 Mbps uplink to contend with. And when
>full-duplex is used on the client side, the magnitude of the
>oversubscription increases again.
>
>CL: In general, I would find it difficult to believe that all machines at
>all times would be pumping 100 mbs into the switch. So that gets into the
>issue of the applications involved. So I guess my question is how one goes
>about determining capacity requirements. I suppose that if LAN based
>videoconferencing is used widely, one's conclusions would be different than
>if the primary application was some kind of TN3270 application. Rule of
>thumb - uplink requirement is X% of the theoretical maximum of the sum of
>all connected workstations and servers?
>
>Properly deploying switches in a shared network environment requires that
>you understand how your network functions--what capacity is required, where
>Fast EtherChannel should be deployed, when 100 Mbps throughput should be
>used and when should 10 Mbps be sufficient... and finally, when should you
>use full-duplex, and when should you use half?
>
>CL: In general, what are some of the considerations that would lead one not
>to prescribe full duplex? Or 10 rather than 100? My own thought is that one
>would create the capability of bandwidth so that it is there when needed.
>Kinda like a stereo system with 350 watts per channel output to the
>speakers. Not that the full 350 is being used all the time, but so that
>during those crescendos, the power is there to deliver the sound without
>distortion.
>
>Capacity planning is the **most** important aspect of a successful
>switch-fabric deployment. Undersubscription of links is always preferable
>to oversubscription.
>
>CL: in this case, I am guessing that you would agree that consideration of
>the backplane capacity of the switch enters into the picture as well. Same
>question as above. Do you folks experienced in switched networks have some
>rule of thumb you use? Or is it as we all do - figure out how much you can
>spend before management's eyes start to pop? :->
>
>Chuck
>----------------------------
>
>
> -- Leigh Anne
>
> > -----Original Message-----
> > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
> > imran obaidullah
> > Sent: Thursday, June 01, 2000 10:58 AM
> > To: [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED]
> > Subject: RE: Network Troubleshooting
> >
> >
> > Hi,
> >
> > Thanks for your information.
> >
> > The server and the clients in the 1st floor are on the switcha
> > and there is
> > a uplink which connects the 2nd floor. But to the surprise the
> > people in 2nd
> > floor are not complaining onlt the clients in the 1st floor started
> > complaining as soon as I changed them from hub to switch .I tried
> > enabling
> > port fast for all the ports except uplink and still they have
> > same problem.
> > Sometimes they can see their neighbour and after few secs you can't see
> > anyone through NN. Know all ports led is howing green colour but
> > when I try
> > it to keep to the auto it completely disable or permanently it
> > shows orange.
> > The NICs are set to auto mode for both the duplex and speed modes.
> >
> > regards
> >
> > imran
>
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