44-20
Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
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Chapter 44 Configuring a VoIP Network
Configuring VoIP on a Switch
Auxiliary VLAN Configuration Guidelines
Follow these guidelines when configuring 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 a dot1q trunk in the
show
trunk
command output, but the port acts like a dot1q trunk if the
set dot1q-all-tagged
command is
enabled.
•
The IP phone and a device attached to the phone are in the same VLAN and must be in the same IP
subnet:
–
If they use the same frame type
–
If the phone uses 802.1p frames and the device uses untagged frames
–
If the phone uses untagged frames and the device uses 802.1p frames
–
If the phone uses 802.1Q frames and the auxiliary VLAN equals the native VLAN
•
The IP phone and a device attached to the phone cannot communicate if they are in the same VLAN
and subnet but use different frame types, because traffic between devices in the same subnet is not
routed (routing would eliminate the frame type difference).
•
You cannot use switch commands to configure the frame type used by traffic received from a device
attached to the phone’s access port.
•
With software release 6.2(1) and later releases, dynamic ports can belong to two VLANs—a native
VLAN and an auxiliary VLAN. See
Chapter 18, “Configuring Dynamic Port VLAN Membership
with VMPS,”
for configuration details for auxiliary VLANs.
Configuring Auxiliary VLANs
To configure auxiliary VLANs, perform this task in privileged mode:
This example shows how to add voice ports to 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 auxiliary VLANs.
set port auxiliaryvlan
mod
[
/ports
] {
vlan
|
untagged
|
dot1p
|
none
}
