[cisco-voip] IP Phone Ports

[Stephen Welsh]

I thought that this would be prevented by default because of spanning tree/BPDU, but it’s common practice to disable spanning tree for access ports (i.e. using portfast) so that may allow the loop to occur, so maybe just disable port-fast?

Kind Regards

Stephen Welsh
CTO

[cid:CBBF0493-235C-43D2-A874-9FB3D95AF598 at b2.unifiedfx.com]

On 10 Nov 2016, at 13:35, Ahmed Elnagar <ahmed_elnagar at hotmail.com<mailto:ahmed_elnagar at hotmail.com>> wrote:

That is not nice at all ☹

Did you figure out a way to prevent it from switch side?

From: Matthew Loraditch [mailto:MLoraditch at heliontechnologies.com]
Sent: Thursday, November 10, 2016 3:34 PM
To: Ahmed Elnagar <ahmed_elnagar at hotmail.com<mailto:ahmed_elnagar at hotmail.com>>; 'cisco-voip at puck.nether.net<mailto:cisco-voip at puck.nether.net>' <cisco-voip at puck.nether.net<mailto:cisco-voip at puck.nether.net>>
Subject: RE: IP Phone Ports

Yes it will create a loop. Not a fun time trying to track these things down. I’ve had some non-Cisco IP phones completely down a LAN.

Matthew G. Loraditch – CCNP-Voice, CCNA-R&S, CCDA
Network Engineer
Direct Voice: 443.541.1518
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From: cisco-voip [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Ahmed Elnagar
Sent: Thursday, November 10, 2016 8:28 AM
To: 'cisco-voip at puck.nether.net<mailto:cisco-voip at puck.nether.net>' <cisco-voip at puck.nether.net<mailto:cisco-voip at puck.nether.net>>
Subject: [cisco-voip] IP Phone Ports

Dear all;

I want to know what will happen if a user connect “by mistake” both the PC port and Switch port to the network switch? Will this create a loop? Anyone tried it before?


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