VoIP Mailing List Archives

[Guest]

Hi all,

I have been googling and testing without any luck and would appreciate
any guidance from anyone.

A port has already been configured on the CISCO switch with the
following:
interface FastEthernet2/0/1
description VOIP VLAN 100
switchport access vlan 100
switchport mode access
duplex full
speed 100

I plugged the phone into the port and everything worked as far as VOIP
is concerned.

Then I plug a PC into the PC port of the Polycom phone with the hope
that I only need one port to support 2 devices.
(I wanted the VOIP phone to use VLAN 100 and PC just the native VLAN)

PROBLEM: However, I found that I could not get the PC (using DHCP) to
get an IP address at all. It seems to be that the traffic from the PC is
also tagged as VLAN 100 as well.
I was told by others that there is a setting on the Polycom phone which
allows the traffic of the PC, under this type of settings, to go native.

Can anyone please help?

Thanks.

[bobg at techie.com]

You can paste and copy nterface FastEthernet2/0/1 switchport access vlan
20 switchport mode access switchport voice vlan 120 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

----- Original Message -----
From: "Lee, John (Sydney)"
To: asterisk-users at lists.digium.com
Subject: [asterisk-users] Polycom IP600 + PC share same switch port
with VLAN
Date: Fri, 29 Feb 2008 16:39:24 +1100
Hi all,

I have been googling and testing without any luck and would
appreciate
any guidance from anyone.

A port has already been configured on the CISCO switch with the
following:
interface FastEthernet2/0/1
description VOIP VLAN 100
switchport access vlan 100
switchport mode access
duplex full
speed 100

I plugged the phone into the port and everything worked as far as
VOIP
is concerned.

Then I plug a PC into the PC port of the Polycom phone with the hope
that I only need one port to support 2 devices.
(I wanted the VOIP phone to use VLAN 100 and PC just the native VLAN)

PROBLEM: However, I found that I could not get the PC (using DHCP) to
get an IP address at all. It seems to be that the traffic from the PC
is
also tagged as VLAN 100 as well.
I was told by others that there is a setting on the Polycom phone
which
allows the traffic of the PC, under this type of settings, to go
native.

Can anyone please help?

Thanks.

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[Guest]

Thanks very much for the quick response.

However, "switchport voice vlan.." I thought is only valid for CISCO phones
and I am using Polycom and thus it would not work.

Furthermore, I have already tried "switchport voice vlan..." before I emailed to the list.
________________________________________
From: asterisk-users-bounces at lists.digium.com [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Bob G
Sent: Friday, 29 February 2008 5:02 PM
To: Asterisk Users Mailing List - Non-Commercial Discussion
Subject: Re: [asterisk-users] Polycom IP600 + PC share same switch port with VLAN

You can paste and copy
?
innterface FastEthernet2/0/1? switchport access vlan 20 switchport mode access?switchport voice vlan 120 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
----- Original Message -----
From: "Lee, John (Sydney)"
To: asterisk-users at lists.digium.com
Subject: [asterisk-users] Polycom IP600 + PC share same switch port with VLAN
Date: Fri, 29 Feb 2008 16:39:24 +1100
Hi all,

I have been googling and testing without any luck and would appreciate
any guidance from anyone.

A port has already been configured on the CISCO switch with the
following:
interface FastEthernet2/0/1
description VOIP VLAN 100
switchport access vlan 100
switchport mode access
duplex full
speed 100

I plugged the phone into the port and everything worked as far as VOIP
is concerned.

Then I plug a PC into the PC port of the Polycom phone with the hope
that I only need one port to support 2 devices.
(I wanted the VOIP phone to use VLAN 100 and PC just the native VLAN)

PROBLEM: However, I found that I could not get the PC (using DHCP) to
get an IP address at all. It seems to be that the traffic from the PC is
also tagged as VLAN 100 as well.
I was told by others that there is a setting on the Polycom phone which
allows the traffic of the PC, under this type of settings, to go native.

Can anyone please help?

Thanks.

_______________________________________________
-- Bandwidth and Colocation Provided by http://www.api-digital.com --

asterisk-users mailing list
To UNSUBSCRIBE or update options visit:
http://lists.digium.com/mailman/listinfo/asterisk-users

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[jsneerin at gmail.com]

As far as I can tell, with Polycom phones you cannot do what you're
asking (which is for the PC and the phone to be in the same VLAN while
the PC is connected to the phone). I don't know how they handle it
when the voice frames are untagged, but they definitely won't pass
tagged voice frames to the PC port:

http://knowledgebase.polycom.com/KanisaPlatform/Publishing/616/12526_f.SAL_PUBLIC_1_2.html

Your switch port is configured for untagged frames on a single VLAN
(that's what "access" mode is). Polycom phones need voice and data to
be on separate VLANs in order for you to use the PC port. Since
Polycom phones apparently don't support the Cisco Voice VLAN feature,
you need to configure the port as a trunk port, which will allow you
to send multiple VLANs to the phone. The phone will take frames tagged
for your designated voice VLAN, and will pass the rest on to the PC
port. For example:

interface FastEthernet2/0/1
switchport trunk encapsulation dot1q
switchport trunk native vlan XXX
switchport trunk allowed vlan XXX,100
switchport mode trunk
spanning-tree portfast trunk

Replace XXX with whatever your PC VLAN is. Setting XXX as the native
VLAN for this port will cause frames in that VLAN to be untagged for
that port, which is what your PC probably expects. If it happens to be
1, then it's the native VLAN by default. The last command may or may
not be available, depending on your version of IOS. If it isn't,
portfast just won't work and you're just stuck with STP negotiation
anytime the port bounces.

-James
On Fri, Feb 29, 2008 at 12:13 AM, Lee, John (Sydney)
<John.Lee at compuware.com> wrote:

[cunningpike at gmail.com]

Have you set the VLAN tag on the phone?

CP

Lee, John (Sydney) wrote:

[Guest]

James, thanks for the suggestion. I am just using native vlan and I did
what you said and I believe it works

interface FastEthernet2/0/2
description VOIP VLAN 100
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,100
switchport mode trunk
duplex full
speed 100

However, when I entered "spanning-tree portfast trunk", I received a
warning message which says:

"Warning: portfast should only be enabled on ports connected to a single
host. Connecting hubs, concentrators, switches, bridges, etc... to this
interface when portfast is enabled, can cause temporary bridging
loops.
Use with CAUTION"

As the polycom phone is acting like a switch, I decided not to put that
option in.

***Also, can I just confirm that with the current QOS (quality of
service) settings on the polycom phones, the phone should have priority
over the PC?

Thanks in advance.

[jsneerin at gmail.com]

Glad it worked for you. The warning is normal for Cisco switches.
Basically, the "portfast" setting disables Spanning Tree (802.1d &
friends) negotiation for the ports. It is only dangerous if you
actually connect that port to another bridging device that could
potentially have an alternate layer-2 path back to the switch (i.e. a
loop).

In the case of your Polycom phones, it is completely safe. It would
only be unsafe if you connected both ports of your phone (the uplink
*and* PC ports) into the switch, which you are unlikely to do. It's up
to you, of course. Without portfast, you're looking at about 30
seconds for STP to negotiate whenever the port bounces, during which
time higher layer protocols are unavailable. This may interfere with
CDP and DHCP, if you're using those.

-James
On Mon, Mar 3, 2008 at 8:57 PM, Lee, John (Sydney)
<John.Lee at compuware.com> wrote: