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<TITLE>RE: [cisco-voip] Switch Hanging off Phone</TITLE>
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<P><FONT SIZE=2>Like Mike suggested.<BR>
<BR>
We use spanning-tree bpduguard enable on all of our access ports.<BR>
I also have ip dhcp snooping enabled on all 3560/3750 in our network and only<BR>
trust the uplinks and valid ports.<BR>
<BR>
<BR>
Just a standard part of my switch configs, can save you some<BR>
headaches in the future because of end user cabling errors or rouge DHCP servers.<BR>
<BR>
I once had a cleaning person wanting to move the CAT5 cable out of the way connect<BR>
the other end of the cable back to the second port in the wall jack, flattened that network.<BR>
<BR>
<BR>
hth<BR>
John Truelove<BR>
<BR>
<BR>
<BR>
<BR>
-----Original Message-----<BR>
From: cisco-voip-bounces@puck.nether.net on behalf of Mike Louis<BR>
Sent: Sun 9/21/2008 11:14 AM<BR>
To: Todd Franklin; Mike Brooks<BR>
Cc: cisco-voip@puck.nether.net<BR>
Subject: Re: [cisco-voip] Switch Hanging off Phone<BR>
<BR>
Why is there no priority out command on this voice port. That could cause issues if you had a broadcast storm on the port from a loop on the network<BR>
<BR>
________________________________<BR>
From: Todd Franklin <toddnh65@gmail.com><BR>
Sent: Saturday, September 20, 2008 3:48 PM<BR>
To: Mike Brooks <2xccie2b@gmail.com><BR>
Cc: cisco-voip@puck.nether.net <cisco-voip@puck.nether.net><BR>
Subject: Re: [cisco-voip] Switch Hanging off Phone<BR>
<BR>
Thanks Mike. The config of the switchport:<BR>
<BR>
interface FastEthernet0/4<BR>
switchport trunk encapsulation dot1q<BR>
switchport mode dynamic desirable<BR>
switchport voice vlan 6<BR>
srr-queue bandwidth share 10 10 60 20<BR>
srr-queue bandwidth shape 10 0 0 0<BR>
mls qos trust device cisco-phone<BR>
mls qos trust cos<BR>
auto qos voip cisco-phone<BR>
spanning-tree portfast<BR>
<BR>
It really screwed around with the phones. The data stayed ok.<BR>
<BR>
He came off from the switchport, into the 7940. From there into the Linksys (which has a built in 4 port switch) and one of those ports he had plugged into his PC.<BR>
<BR>
What do you think?<BR>
<BR>
Todd<BR>
<BR>
On Sat, Sep 20, 2008 at 3:38 PM, Mike Brooks <2xccie2b@gmail.com<<A HREF="mailto:2xccie2b@gmail.com">mailto:2xccie2b@gmail.com</A>>> wrote:<BR>
What was the configuration of the switchport ? Also was the data vlan<BR>
affected at all or just devices on the voice vlan ? A common issue we<BR>
have seen with hubs plugged in is them getting mis-cabled by the<BR>
enduser and getting looped up causing major issues on the network. I<BR>
do not believe the linksys devices send BPDUs. If it was a cabling<BR>
issue on the linksys ..then enabling bpduguard on the port will<BR>
errdisable the port..because the port will receive its own bpdu if the<BR>
linksys is miscabled.<BR>
<BR>
Also, the linksys could have been acting as a rouge dhcp server. Not<BR>
knowing how your network is set up or the symptoms you were<BR>
experiencing it would be hard to tell.<BR>
<BR>
Just a few guesses ;-)<BR>
<BR>
hth,<BR>
<BR>
Mike Brooks<BR>
CCIE# 16027 (R&S)<BR>
<BR>
On Sat, Sep 20, 2008 at 3:10 PM, Todd Franklin <toddnh65@gmail.com<<A HREF="mailto:toddnh65@gmail.com">mailto:toddnh65@gmail.com</A>>> wrote:<BR>
> Phone system went "kerflunk" yesterday. Found a 7940 with a Linksysy<BR>
> wireless router plugged into the PC port of the phone. Could that have done<BR>
> it? I seem to remember one VAR telling me this was a grand way to take an<BR>
> IPT network down.<BR>
><BR>
> Also, is there any configuration I can add to the 3560s that would<BR>
> "disallow" this configuration?<BR>
><BR>
> Thank you!<BR>
><BR>
> Todd<BR>
> _______________________________________________<BR>
> cisco-voip mailing list<BR>
> cisco-voip@puck.nether.net<<A HREF="mailto:cisco-voip@puck.nether.net">mailto:cisco-voip@puck.nether.net</A>><BR>
> <A HREF="https://puck.nether.net/mailman/listinfo/cisco-voip">https://puck.nether.net/mailman/listinfo/cisco-voip</A><BR>
><BR>
><BR>
<BR>
<BR>
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