From: Vincent Mashburn (vmashburn@fedex.com)
Date: Wed Mar 22 2006 - 11:56:51 GMT-3
I am not saying that it is totally dependant on CDP. I am just saying
that you don't need to configure 802.1q trunks when utilizing a complete
Cisco environment. The new enhancements to CDP allow voice VLAN info to
be propagated. Why would this be included if it is not to be used? The
Data VLAN is applied to the switchport via "switchport access vlan
<vlan>" and the voice VLAN is applied via "switchport voice vlan
<vlan>". When you are using Cisco phones and using the integrated
switchport within the Cisco phone, the VLAN information is indeed
propagated to the phone via CDP. I know this because you configure the
switchport as an access port and not a trunk port. The phone then
assigns the switchport connecting to the PC to the "switchport access
vlan <vlan>" and the phone assigns itself to the "switchport voice vlan
<vlan>". DHCP can be utilized in this fashion, but I have only been
able to get the TFTP server info to be propagated to the phones via the
option 150 (or option 60). I have not seen an option to propagate VLAN
information. Could you send me that config? I would be very interested
to learn how to do that. Also, whenever I hardcode the voice VLAN on
the phone, it gets overridden by the CDP propagated voice VLAN.
Vince Mashburn
Voice / Data Engineer
901-263-5072
Cisco IP Telephony Support Specialist
CCIE (R&S Written), CCNP, CCDA,Network +
________________________________
From: James Ventre [mailto:messageboard@ventrefamily.com]
Sent: Wednesday, March 22, 2006 8:42 AM
To: Vincent Mashburn
Cc: Vishal Patel; david robin; Cisco certification
Subject: Re: Voice vlan
Using the voice vlan is not dependent on CDP! How you tell the
telephone about the trunk is dependent on CDP, DHCP or hardcoding it. I
happen to be using DHCP.
The native vlan is the access vlan and the tagged vlan is the voice
vlan.
James
Switch>sh int fa0/1 trunk
Port Mode Encapsulation Status Native vlan
Fa0/1 off negotiate not-trunking 1
Port Vlans allowed on trunk
Fa0/1 209,227
Port Vlans allowed and active in management domain
Fa0/1 209,227
Port Vlans in spanning tree forwarding state and not pruned
Fa0/1 209,227
Switch#sh run int fa0/1
Building configuration...
Current configuration : 442 bytes
!
interface FastEthernet0/1
description { phone and pc }
switchport access vlan 227
switchport mode access
switchport voice vlan 209
service-policy input IP-Telephony
no logging event link-status
no logging event power-inline-status
no mdix auto
storm-control broadcast level 4.00
storm-control multicast level 2.00
no cdp enable
spanning-tree portfast
spanning-tree bpduguard enable
spanning-tree guard root
end
Vincent Mashburn wrote:
If you are using Avaya Phones, then you can't use cdp. Trunking is your
only option.
Vince Mashburn
Voice / Data Engineer
901-263-5072
Cisco IP Telephony Support Specialist
CCNP, CCDA,Network +
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