Default Layer 2 Protocol Tunneling Configuration - Cisco WS-C3020 Software Configuration Manual

Chapter 15 Configuring IEEE 802.1Q and Layer 2 Protocol Tunneling
See
Asymmetric links connect the customers in Site 1 to edge switches in the service-provider network. The
Layer 2 PDUs (for example, BPDUs) coming into Switch 2 from Customer Y in Site 1 are forwarded to
the infrastructure as double-tagged packets with the well-known MAC address as the destination MAC
address. These double-tagged packets have the metro VLAN tag of 40, as well as an inner VLAN tag
(for example, VLAN 100). When the double-tagged packets enter Switch D, the outer VLAN tag 40 is
removed, the well-known MAC address is replaced with the respective Layer 2 protocol MAC address,
and the packet is sent to Customer Y on Site 2 as a single-tagged frame in VLAN 100.
You can also enable Layer 2 protocol tunneling on access ports on the edge switch connected to access
or trunk ports on the customer switch. In this case, the encapsulation and decapsulation process is the
same as described in the previous paragraph, except that the packets are not double-tagged in the
service-provider network. The single tag is the customer-specific access VLAN tag.
These sections contain this configuration information:
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Default Layer 2 Protocol Tunneling Configuration

Table 15-1
Table 15-1
Feature
Layer 2 protocol tunneling
Shutdown threshold
Drop threshold
CoS value
OL-8915-03
Figure 15-4, with Customer X and Customer Y in access VLANs 30 and 40, respectively.
Default Layer 2 Protocol Tunneling Configuration, page 15-11
Layer 2 Protocol Tunneling Configuration Guidelines, page 15-12
Configuring Layer 2 Protocol Tunneling, page 15-13
Configuring Layer 2 Tunneling for EtherChannels, page 15-14
shows the default Layer 2 protocol tunneling configuration.
Default Layer 2 Ethernet Interface VLAN Configuration
Default Setting
Disabled.
None set.
None set.
If a CoS value is configured on the interface for data packets, that
value is the default used for Layer 2 PDUs. If none is configured,
the default is 5.
Cisco Catalyst Blade Switch 3020 for HP Software Configuration Guide
Configuring Layer 2 Protocol Tunneling
15-11