From: Church, Chuck (cchurch@multimax.com)
Date: Mon Jul 10 2006 - 17:10:24 ART
Thanks. I've been doing it like this as a workaround. I thought it
would be auto-negotiated, as all the docs for the 2900XL seem to
indicate it will. This workaround seems to keep everything working, but
I had an odd issue crop up. It seems that the phones 'exist' on both
VLANs when I use the manually-configured trunk. Here is one:
Non-static Address Table:
Destination Address Address Type VLAN Destination Port
------------------- ------------ ---- --------------------
000f.8fa4.981e Dynamic 251 FastEthernet0/5
000f.8fa4.981e Dynamic 252 FastEthernet0/5
That MAC add belongs to the Cisco phone. I suppose it could be the
phone just sending out BPDUs on the native VLAN that is causing it to
populate both VLANs. The odd part that I was trying to fix was that a
phone booting up seems to pull a DHCP address from the non-VoIP VLAN.
I'm wondering if I have the switch ports do CDP announcements for
frequent than once a minute, if it'll help the phones learn the Voice
VLAN quicker and not try to use untagged packets for DHCP requests...
Thanks,
Chuck
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Guyler, Rik
Sent: Monday, July 10, 2006 10:31 AM
To: 'ccielab@groupstudy.com'
Subject: RE: OT - Cisco phones and Voice VLAN
Chuck, as I recall you need to add the "switchport native vlan 251" and
"switchport mode trunk" lines to your config. The old 2900s don't use
DTP
so you have to manually config the interface to be trunk and then use
the
native vlan concept to define the data vlan. Here's the config from a
production 3524XL I setup a few years ago, which should be about the
same:
interface FastEthernet0/3
switchport trunk encapsulation dot1q
switchport trunk native vlan 10
switchport mode trunk
switchport voice vlan 20
spanning-tree portfast
Rik
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Church, Chuck
Sent: Monday, July 10, 2006 9:20 AM
To: Cisco certification
Subject: OT - Cisco phones and Voice VLAN
Hey all,
Sorry about the OT, but I'm having trouble getting some Cisco IP
phones to work correctly with older 2900XL switches. The switches are
the 8
mb variety, and running the latest 12.0 software. The config on the
switch
looks like this:
interface FastEthernet0/16
switchport access vlan 251
switchport trunk encapsulation dot1q
switchport voice vlan 252
spanning-tree portfast
Looking around CCO seems to indicate this is the correct way to
do
it. From the phone's menu, I can see it's being given VLAN 252 for it's
admin VLAN. But when I look on the switch, the phone's MAC address
shows up
in VLAN 251 only. So the phone is being told correctly about voice
VLAN,
but it's either not tagging it's traffic with 252 like it should, or the
switch is ignoring it. Any ideas?
Thanks,
Chuck Church
Network Engineer
CCIE #8776, MCNE, MCSE
Multimax, Inc.
Enterprise Network Engineering
Home Office - 864-335-9473
Cell - 864-266-3978
cchurch@multimax.com
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