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Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
OL-8978-04
Chapter 55 Configuring a VoIP Network
Configuring VoIP on a Switch
Auxiliary VLAN Configuration Guidelines
This section describes the guidelines for configuring the auxiliary VLANs:
•
An auxiliary VLAN port is operationally a trunk, even though it is not treated like a “normal” trunk
port. When an auxiliary VLAN is added to a port and the
set dot1q-all-tagged
command is enabled,
the
set dot1q-all-tagged
command tags the native VLAN on the port where the auxiliary VLAN is
configured. A port with an auxiliary VLAN configured is not viewed as an 802.1Q trunk in the
show
trunk
command output, but the port acts like an 802.1Q trunk if the
set dot1q-all-tagged
command
is enabled.
•
The IP phone and a device that is attached to the phone are in the same VLAN and must be in the
same IP subnet if one of the following occurs:
–
They use the same frame type.
–
The phone uses 802.1p frames, and the device uses untagged frames.
–
The phone uses untagged frames, and the device uses 802.1p frames.
–
The phone uses 802.1Q frames, and the auxiliary VLAN equals the native VLAN.
•
The IP phone and a device that is attached to the phone cannot communicate if they are in the same
VLAN and subnet but use different frame types, because the traffic between the devices in the same
subnet is not routed (routing would eliminate the frame type difference).
•
You cannot use the switch commands to configure a frame type that is used by the traffic that is
received from a device that is attached to the phone’s access port.
•
With software release 6.2(1) and later releases, the dynamic ports can belong to two VLANs—a
native VLAN and an auxiliary VLAN. See
Chapter 19, “Configuring Dynamic Port VLAN
Membership with VMPS,”
for the configuration details for the auxiliary VLANs.
Configuring the Auxiliary VLANs
To configure the auxiliary VLANs, perform this task in privileged mode:
This example shows how to add the voice ports to the auxiliary VLANs, specify an encapsulation type,
or specify that the VLAN will not send or receive CDP messages with voice-related information:
Console> (enable)
set port auxiliaryvlan 2/1-3 222
Auxiliaryvlan 222 configuration successful.
AuxiliaryVlan AuxVlanStatus Mod/Ports
------------- ------------- -------------------------
222 active 1/2,2/1-3
Console> (enable)
set port auxiliaryvlan 5/7 untagged
Port 5/7 allows the connected device send and receive untagged packets and without 802.1p
priority.
Console> (enable)
set port auxiliaryvlan 5/9 dot1p
Port 5/9 allows the connected device send and receive packets with 802.1p priority.
Console> (enable)
set port auxiliaryvlan 5/12 none
Port 5/12 will not allow sending CDP packets with Voice VLAN information.
Console> (enable)
Task
Command
Configure the auxiliary VLANs.
set port auxiliaryvlan
mod
[
/ports
] {
vlan
|
untagged
|
dot1p
|
none
}
