[124231] in North American Network Operators' Group
Re: Auto MDI/MDI-X + conference rooms + bored == loop
daemon@ATHENA.MIT.EDU (Mike Lyon)
Fri Mar 26 18:14:29 2010
In-Reply-To: <20100326220922.GH12189@angus.ind.WPI.EDU>
Date: Fri, 26 Mar 2010 15:13:43 -0700
From: Mike Lyon <mike.lyon@gmail.com>
To: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Disable the jacks all together and go wireless? Have them put in a trouble
ticket if they absolutely need a port activated in a conference room for a
one-time meeting.
-Mike
On Fri, Mar 26, 2010 at 3:09 PM, Chuck Anderson <cra@wpi.edu> wrote:
> Anyone have suggestions on Ethernet LAN loop-prevention? With the
> advent of Auto MDI/MDI-X ports on switches, it seems way too easy to
> accidentally or maliciously create loops between network jacks. We
> have bored or inattentive people plugging in patch cords between
> adjacent network jacks. STP for loop-prevention isn't working so well
> for us.
>
> STP "edge" or "portfast" or "faststart" modes are required for
> end-station ports (with normal STP, DHCP often times out after 30+
> seconds it takes to go into Forwarding state). Since the "edge" STP
> mode goes into Forwarding state immediately, there is a period when
> loops will form, causing havok with upstream gear until STP blocks the
> port (if it ever does see below).
>
> "Desktop" switches. You know, those 4 or 5 port Gigabit Ethernet
> switches. Apparently, many of them don't do any kind of STP at all.
> Recommendations on ones that do STP?
>
> RSTP: is it any better than traditional STP in regards to "edge" ports
> and blocking before a loop gets out of hand? Or perhaps blocking for
> 5-10 seconds before going into Forwarding state, hopefully preventing
> loops before they happen but also allowing DHCP clients to get an
> address without timeouts? Recommendations on "Desktop" switches that
> do RSTP?
>
> Thanks for your suggestions/discussion.
>
> --
> - Chuck (354 Days until IPv4 depletion: http://ipv4depletion.com/)
>
>
