Configuring Ieee 802.1Q Tunneling; Default Ieee 802.1Q Tunneling Configuration; Ieee 802.1Q Tunneling Configuration Guidelines; Native Vlans - Cisco WS-CBS3032-DEL Software Configuration Manual

Configuring IEEE 802.1Q Tunneling

Configuring IEEE 802.1Q Tunneling
These sections contain this configuration information:
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Default IEEE 802.1Q Tunneling Configuration

By default, IEEE 802.1Q tunneling is disabled because the default switchport mode is dynamic auto.
Tagging of IEEE 802.1Q native VLAN packets on all IEEE 802.1Q trunk ports is also disabled.

IEEE 802.1Q Tunneling Configuration Guidelines

When you configure IEEE 802.1Q tunneling, you should always use an asymmetrical link between the
customer device and the edge switch, with the customer device port configured as an IEEE 802.1Q trunk
port and the edge switch port configured as a tunnel port.
Assign tunnel ports only to VLANs that are used for tunneling.
Configuration requirements for native VLANs and for and maximum transmission units (MTUs) are
explained in these next sections.

Native VLANs

When configuring IEEE 802.1Q tunneling on an edge switch, you must use IEEE 802.1Q trunk ports for
sending packets into the service-provider network. However, packets going through the core of the
service-provider network can be carried through IEEE 802.1Q trunks or nontrunking links. When IEEE
802.1Q trunks are used in these core switches, the native VLANs of the IEEE 802.1Q trunks must not
match any native VLAN of the nontrunking (tunneling) port on the same switch because traffic on the
native VLAN would not be tagged on the IEEE 802.1Q sending trunk port.
See
Customer X at the ingress edge switch in the service-provider network (Switch B). Switch A of
Customer X sends a tagged packet on VLAN 30 to the ingress tunnel port of Switch B in the
service-provider network, which belongs to access VLAN 40. Because the access VLAN of the tunnel
port (VLAN 40) is the same as the native VLAN of the edge-switch trunk port (VLAN 40), the metro
tag is not added to tagged packets received from the tunnel port. The packet carries only the VLAN 30
tag through the service-provider network to the trunk port of the egress-edge switch (Switch C) and is
misdirected through the egress switch tunnel port to Customer Y.
Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
17-4
Default IEEE 802.1Q Tunneling Configuration, page 17-4
IEEE 802.1Q Tunneling Configuration Guidelines, page 17-4
IEEE 802.1Q Tunneling and Other Features, page 17-6
Configuring an IEEE 802.1Q Tunneling Port, page 17-6
Figure 17-3. VLAN 40 is configured as the native VLAN for the IEEE 802.1Q trunk port from
Chapter 17 Configuring IEEE 802.1Q and Layer 2 Protocol Tunneling
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