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Cisco ME 3400 EthernetAccess Switch SoftwareConfiguration Guide
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Chapter11 Configuring VLANs
Creating and Modifying VLANs
•UNI community VLAN—Local switching is allowed among UNIs on the switch that belong to the
same UNI community VLAN. If UNIs belong to the same customer, and you want to switch packets
between the ports, you can configure the common VLAN as a UNI community VLAN. There is no
local switching between ports in a UNI community VLAN and ports outside of the VLAN. The
switch does not support more than eight UNIs in a UNI community VLAN.
Network node interfaces (NNIs) are not affected by the type of UNI VLAN to which they belong.
Switching can occur between NNIs and other NNIs or UNIs on the switch or other switches that are part
of the same VLAN, regardless of VLAN type.
In the configuration in Figure11-2, if VLAN 10 is a UNI isolated VLAN and VLAN 20 is a UNI
community VLAN, local switching does not take place among Fast Ethernet ports 1-4, but local
switching can occur between Fast Ethernet ports 6-10. The NN Is i n b oth VLA N 10 a nd V LAN 2 0 ca n
exchange packets with the UNIs in the same VLAN.
Figure11-2 UNI Isolated and Community VLANs in the Cisco ME Switch
A UNI can be an access port, a trunk port, a private VLAN port, or an IEEE 802.1Q tunnel port. It can
also be a member of an EtherChannel.
When a UNI configured as an IEEE 802.1Q trunk port belongs to a UNI isolated VLAN, the VLAN on
the trunk is isolated from the same VLAN ID on a different trunk port or an access port. Other V L ANs
on the trunk port can be of different types (private VLAN, UNI comm unit y VLA N, an d s o o n) . For
example, a UNI access port and one VLAN on a UNI trunk port can belong to the same UNI isolated
VLAN. In this case, isolation occurs between the UNI access port and the VLAN on the UNI trunk port.
Other access ports and other VLANs on the trunk port are isolated because they belong to different
VLANs.
UNIs and NNIs are always isolated from ports on different VLANs.
Creating and Modifying VLANs
You use VLAN configuration mode, accessed by entering the vlan global configuration command to
create VLANs and to modify some parameters. You use the interface configuration mode to define the
port membership mode and to add and remove ports from VLANs. The results of these commands are
written to the running-configuration file, and you can display the file by entering the show
running-config privileged EXEC command.
To service-provider network
VLAN 10:
(UNI isolated VLAN)
Fast Ethernet
ports 1 – 4 Fast Ethernet
ports 6 – 10
VLAN 20:
(UNI community VLAN)
NNIs
NNIs
Customer-facing ports
Gigabit Ether
Gigabit Ether
net port 1 Gigabit Ether
Gigabit Ether
net port 2Gigabit Ethernet port 1 Gigabit Ethernet port 2
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