[cisco-voip] Switch Hanging off Phone

[Todd Franklin]

no, not plugged back into the walljack.

But the whole phone setup went wild yesterday around 6PM, and he "moved the
network equipment on my desk around" around 6PM yesterday.  Sure seems a
likely culprit!

On Sat, Sep 20, 2008 at 2:58 PM, Matlock, Kenneth L <MatlockK at exempla.org>wrote:

> Are you sure that one of the ports off the linksys wasn't 'accidentally'
> plugged back into a wall jack (and essentially into the upstream switch)?
>
> Very easy to bridge 2 VLANs doing that, and that will almost definitely
> affect one (or both) of them.
>
> What VLAN is used for the data traffic? I believe by default most 'switch'
> gear uses VLAN 1 by default, and if it was spitting out STP or VTP data,
> that could cause serious issues, depending on your topology.
>
> Ken Matlock
> matlockk at exempla.org
> (303) 467-4671
> Network Analyst
> Exempla Healthcare
>
> ________________________________
>
> From: cisco-voip-bounces at puck.nether.net on behalf of Todd Franklin
> Sent: Sat 9/20/2008 1:47 PM
> To: Mike Brooks
> Cc: cisco-voip at puck.nether.net
> Subject: Re: [cisco-voip] Switch Hanging off Phone
>
>
> Thanks Mike.  The config of the switchport:
>
> interface FastEthernet0/4
>  switchport trunk encapsulation dot1q
>  switchport mode dynamic desirable
>  switchport voice vlan 6
>  srr-queue bandwidth share 10 10 60 20
>  srr-queue bandwidth shape  10  0  0  0
>  mls qos trust device cisco-phone
>  mls qos trust cos
>  auto qos voip cisco-phone
>  spanning-tree portfast
>
> It really screwed around with the phones.  The data stayed ok.
>
> 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.
>
> What do you think?
>
> Todd
>
>
> On Sat, Sep 20, 2008 at 3:38 PM, Mike Brooks <2xccie2b at gmail.com> wrote:
>
>
>        What was the configuration of the switchport ?  Also was the data
> vlan
>        affected at all or just devices on the voice vlan ?  A common issue
> we
>        have seen with hubs plugged in is them getting mis-cabled by the
>        enduser and getting looped up causing major issues on the network.
>  I
>        do not believe the linksys devices send BPDUs.  If it was a cabling
>        issue on the linksys ..then enabling bpduguard on the port will
>        errdisable the port..because the port will receive its own bpdu if
> the
>        linksys is miscabled.
>
>        Also, the linksys could have been acting as a rouge dhcp server.
>  Not
>        knowing how your network is set up or the symptoms you were
>        experiencing it would be hard to tell.
>
>        Just a few guesses ;-)
>
>        hth,
>
>        Mike Brooks
>        CCIE# 16027 (R&S)
>
>
>        On Sat, Sep 20, 2008 at 3:10 PM, Todd Franklin <toddnh65 at gmail.com>
> wrote:
>        > Phone system went "kerflunk" yesterday.  Found a 7940 with a
> Linksysy
>        > wireless router plugged into the PC port of the phone.  Could that
> have done
>        > it?  I seem to remember one VAR telling me this was a grand way to
> take an
>        > IPT network down.
>        >
>        > Also, is there any configuration I can add to the 3560s that would
>        > "disallow" this configuration?
>        >
>        > Thank you!
>        >
>        > Todd
>
>        > _______________________________________________
>        > cisco-voip mailing list
>        > cisco-voip at puck.nether.net
>        > https://puck.nether.net/mailman/listinfo/cisco-voip
>        >
>        >
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/cisco-voip/attachments/20080920/35667b38/attachment.html>