Sure but networks are never built on human delay factors if they were we
would still be using 2mb ARCNet.
Surely clearing a CAM entry takes no time at all and is the path of less
resistance. Also no one had mention spanning tree. The duplicate MAC entries
will force spanning tree to converge (50 seconds) assuming they are moved to
the same VLAN on the same switch but different ports. Also if the server is
routing and participating in level three dynamic routing protocol (Unix
running route-d - rip v1) you have to factor in layer three convergence as
well. Not to mention if you are dual homing to two core switches HSRP
becomes a factor as well because you have to ensure that layer (spanning
tree) and layer three convergence (HSRP and dynamic routing)are configured
properly so that the active layer two links matches the active core switch
from a layer three perspective. All are factors in convergence.
Mike
-----Original Message-----
From: Chuck Larrieu [mailto:[EMAIL PROTECTED]]
Sent: Friday, July 07, 2000 12:20 AM
To: Jorge Rodriguez; [EMAIL PROTECTED]; Roberta J. Flinn
Cc: Jay Cann; BURGESS, MICHAEL (AIT)
Subject: RE: Fw: Easy Brain Teaser (Switching)
Realistically, how much time does it take to move a department? Some folks
do things like this evenings or weekends. By the time the movees get back to
work, the CAM table is no longer an issue.
Chuck
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of
Jorge Rodriguez
Sent: Thursday, July 06, 2000 1:13 PM
To: [EMAIL PROTECTED]; Roberta J. Flinn
Cc: Jay Cann; Michael Burgess
Subject: RE: Fw: Easy Brain Teaser (Switching)
This is a very interesting issue that must have a work around,
specially when moving workstation/servers to other locations.
Sure, one server is ok, what about moving a whole department
from one Cat5000 to another ? or if you schedule Station moves
on a weekly basis ? Do you want to clear cam all the time ?
I don't think so !-:) Maybe Cisco has some answers to these type of
scenarios.
In the server scenario I would instead of "Clear cam dyn ", issue
a "clear cam Mac_Address Vlan#"" for that server if is going to a different
port on the same switch, this way the switch will not have to rebuild the
MAC table.
------Original Message------
From: "Roberta J. Flinn" <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
Sent: July 6, 2000 6:43:42 PM GMT
Subject: Fw: Easy Brain Teaser (Switching)
This has to do with the learning (cam table) in the switch. The entries are
set to age out of that table after a preset number of minutes. Until the
older entry "ages out" the switch will see the same MAC address on two
different ports. It cannot make a switching decision so it does not send to
either port. To solve this issue - you can issue a "clear cam dynamic"
command. This will flush the CAM table and force the switch to rebuild it
with the correct information. (Note: can cause additional traffic for a few
moments because the switch will flood packets destined for unknown MAC
addresses out all ports except the one from which it received the packet.)
Roberta J. Flinn
CCDP, CCNA, MCNE, MCSE
----- Original Message -----
From: "John Neiberger" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, July 06, 2000 8:04 AM
Subject: Easy Brain Teaser (Switching)
> Here's an easy one, because I'm nicer than Chuck. :-) Even though it's
> easy, it's still practical. And for those of you who immediately know the
> answer, let the less experienced people mull this one over for a bit.
>
> You have a Catalyst 5000 with several servers connected and you've decided
> to rearrange the port assignments. You disconnect one server in
> particular
> > and move it to another port, then quickly discover that it now has no
> > network connectivity. You attempt to access the network for a couple of
> > minutes to no avail. In supreme frustration, you head to the break room
> for
> > coffee and donuts.
> >
> > When you come back several minutes later you find that the server now
has
> > network connectivity and all is well, no problems.
> >
> > What is the most likely cause of this behavior and what could you have
> done
> > to remedy the situation immediately?
> >
> > Good luck!
> >
> > John
> >
> >
> >
> >
> >
> > _______________________________________________________
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>
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Jorge Rodriguez /CCNA
Network Analyst
R&S Networks Inc
1112 Boylston Street
Suite 222
Boston, MA 02115
1-781-614-1294
http://www.netwire.n3.net/
http://www.learncisco.n3.net/
........................................................
iWon.com http://www.iwon.com why wouldn't you?
........................................................
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