Catalyst 3550 Multilayer Switch Software Configuration Guide, 12.1(13)EA1
Configuring 802.1Q and Layer 2 Protocol Tunneling
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Configuring 802.1Q and Layer 2 Protocol Tunneling

Table Of Contents

Configuring 802.1Q and Layer 2 Protocol Tunneling

Understanding 802.1Q Tunneling

Configuring 802.1Q Tunneling

Default 802.1Q Tunneling Configuration

802.1Q Tunneling Configuration Guidelines

Native VLANs

System MTU

802.1Q Tunneling and Other Features

Configuring an 802.1Q Tunneling Port

Understanding Layer 2 Protocol Tunneling

Configuring Layer 2 Protocol Tunneling

Default Layer 2 Protocol Tunneling Configuration

Layer 2 Protocol Tunneling Configuration Guidelines

Configuring Layer 2 Tunneling Characteristics

Monitoring and Maintaining Tunneling Status


Configuring 802.1Q and Layer 2 Protocol Tunneling


Virtual private networks (VPNs) provide enterprise-scale connectivity on a shared infrastructure, often Ethernet-based, with the same security, prioritization, reliability, and manageability requirements of private networks. Tunneling is a feature designed for service providers who carry traffic of multiple customers across their networks and are required to maintain the VLAN and Layer 2 protocol configurations of each customer without impacting the traffic of other customers. The Catalyst 3550 switch supports 802.1Q tunneling and Layer 2 protocol tunneling.


Note For complete syntax and usage information for the commands used in this chapter, refer to the command reference for this release.


This chapter contains these sections:

Understanding 802.1Q Tunneling

Configuring 802.1Q Tunneling

Understanding Layer 2 Protocol Tunneling

Configuring Layer 2 Protocol Tunneling

Monitoring and Maintaining Tunneling Status

Understanding 802.1Q Tunneling

Business customers of service providers often have specific requirements for VLAN IDs and the number of VLANs to be supported. The VLAN ranges required by different customers in the same service-provider network might overlap, and traffic of customers through the infrastructure might be mixed. Assigning a unique range of VLAN IDs to each customer would restrict customer configurations and could easily exceed the VLAN limit of 4096 of the 802.1Q specification.

Using the 802.1Q tunneling feature, service providers can use a single VLAN to support customers who have multiple VLANs. Customer VLAN IDs are preserved and traffic from different customers is segregated within the service-provider infrastructure even when they appear to be on the same VLAN. The 802.1Q tunneling expands VLAN space by using a VLAN-in-VLAN hierarchy and tagging the tagged packets. A port configured to support 802.1Q tunneling is called a tunnel port. When you configure tunneling, you assign a tunnel port to a VLAN that is dedicated to tunneling. Each customer requires a separate VLAN, but that VLAN supports all of the customer's VLANs.

Customer traffic tagged in the normal way with appropriate VLAN IDs come from an 802.1Q trunk port on the customer device and into a tunnel port on the service-provider edge switch. The link between the customer device and the edge switch is an asymmetric link because one end is configured as an 802.1Q trunk port and the other end is configured as a tunnel port. You assign the tunnel port interface to an access VLAN ID unique to each customer. See Figure 14-1.

Figure 14-1 802.1Q Tunnel Ports in a Service-Provider Network

Packets coming from the customer trunk port into the tunnel port on the service-provider edge switch are normally 802.1Q-tagged with the appropriate VLAN ID. The tagged packets remain intact inside the switch and, when they exit the trunk port into the service-provider network, are encapsulated with another layer of an 802.1Q tag (called the metro tag) that contains the VLAN ID unique to the customer. The original 802.1Q tag from the customer is preserved in the encapsulated packet. Therefore, packets entering the service-provider infrastructure are double-tagged, with the outer tag containing the customer's access VLAN ID, and the inner VLAN ID being the VLAN of the incoming traffic.

When the double-tagged packet enters another trunk port in a service-provider core switch, the outer tag is stripped as the packet is processed inside the switch. When the packet exits another trunk port on the same core switch, the same metro tag is again added to the packet. Figure 14-2 shows the structure of the double-tagged packet.

Figure 14-2 Normal, 802.1Q, and Double-Tagged Ethernet Packet Formats

When the packet enters the trunk port of the service-provider egress switch, the outer tag is again stripped as the packet is processed internally on the switch. However, the metro tag is not added when it is sent out the tunnel port on the edge switch into the customer network, and the packet is sent as a normal 802.1Q-tagged frame to preserve the original VLAN numbers in the customer network.

In Figure 14-1, Customer A was assigned VLAN 30, and Customer B was assigned VLAN 40. Packets entering the edge switch tunnel ports with 802.1Q tags are double-tagged when they enter the service-provider network, with the outer tag containing VLAN ID 30 or 40, appropriately, and the inner tag containing the original VLAN number, for example, VLAN 100. Even if both Customers A and B have VLAN 100 in their networks, the traffic remains segregated within the service-provider network because the outer tag is different. With 802.1Q tunneling, each customer controls its own VLAN numbering space, which is independent of the VLAN numbering space used by other customers and the VLAN numbering space used by the service-provider network.

At the outbound tunnel port, the original VLAN numbers on the customer's network are recovered. It is possible to have multiple levels of tunneling and tagging, but the switch supports only one level in this release.

If the traffic coming from a customer network is not tagged (native VLAN frames), these packets are bridged or routed as if they were normal packets. All packets entering the service-provider network through a tunnel port on an edge switch are treated as untagged packets, whether they are untagged or already tagged with 802.1Q headers. The packets are encapsulated with the metro tag VLAN ID (set to the access VLAN of the tunnel port) when they are sent through the service-provider network on an 802.1Q trunk port. The priority field on the metro tag is set to the interface class of service (CoS) priority configured on the tunnel port (the default is zero if none is configured).

Configuring 802.1Q Tunneling

This section includes this information about configuring 802.1Q tunneling:

Default 802.1Q Tunneling Configuration

802.1Q Tunneling Configuration Guidelines

802.1Q Tunneling and Other Features

Configuring an 802.1Q Tunneling Port

Default 802.1Q Tunneling Configuration

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

802.1Q Tunneling Configuration Guidelines

When you configure 802.1Q tunneling, you should always use asymmetrical links for traffic going in or out of a tunnel and dedicate one VLAN for each tunnel. You should also be aware of configuration requirements for native VLANs and maximum transmission units (MTUs).

Native VLANs

When configuring 802.1Q tunneling on an edge switch, you must use 802.1Q trunk ports for sending out packets into the service-provider network. However, packets going through the core of the service-provider network might be carried through 802.1Q trunks, ISL trunks, or nontrunking links. When 802.1Q trunks are used in these core switches, the native VLANs of the 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 802.1Q transmitting trunk port.

See Figure 14-3. VLAN 40 is configured as the native VLAN for the 802.1Q trunk port from Customer A at the ingress edge switch in the service-provider network (Switch 2). Switch 1 of Customer A sends a tagged packet on VLAN 30 to the ingress tunnel port of Switch 2 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 3) and is misdirected through the egress switch tunnel port to Customer B.

These are some ways to solve this problem:

Use ISL trunks between core switches in the service-provider network. Although customer interfaces connected to edge switches must be 802.1Q trunks, we recommend using ISL trunks for connecting switches in the core layer.

Configure the edge switch so that all packets going out an 802.1Q trunk, including the native VLAN, are tagged by using the vlan dot1q tag native global configuration command. If the switch is configured to tag native VLAN packets on all 802.1Q trunks, the switch accepts untagged packets, but sends only tagged packets.

Ensure that the native VLAN ID on the edge switch trunk port is not within the customer VLAN range. For example, if the trunk port carries traffic of VLANs 100 to 200, assign the native VLAN a number outside that range.

Figure 14-3 Potential Problem with 802.1Q Tunneling and Native VLANs

System MTU

The default system MTU for traffic on the Catalyst 3550 switch is 1500 bytes. You can configure the switch to support frames larger than 1500 bytes by using the system mtu global configuration command. Because the 802.1Q tunneling feature increases the frame size by 4 bytes when the metro tag is added, you must configure all switches in the service-provider network to be able to process maximum frames by increasing the switch system MTU size to at least 1504 bytes. The maximum allowable system MTU for Catalyst 3550 Gigabit Ethernet switches is 2000 bytes; the maximum system MTU for Fast Ethernet switches is 1546 bytes.

802.1Q Tunneling and Other Features

Although 802.1Q tunneling works well for Layer 2 packet switching, there are incompatibilities with some Layer 2 features and with Layer 3 switching.

A tunnel port cannot be a routed port.

IP routing is not supported on a VLAN that includes 802.1Q ports. Packets received from a tunnel port are forwarded based only on Layer 2 information. If routing is enabled on the switch virtual interface (SVI) that includes tunnel ports, untagged IP packets received from the tunnel port are recognized and routed by the switch. This allows the customer to access the internet through its native VLAN. If this access is not required, you should not configure SVIs on VLANs that include tunnel ports.

Fallback bridging is not supported on tunnel ports. Because all 802.1Q-tagged packets received from a tunnel port are treated as non-IP packets, if fallback bridging is enabled on VLANs that have tunnel ports configured, IP packets would be improperly bridged across VLANs. Therefore, you must not enable fallback bridging on VLANs with tunnel ports.

Tunnel ports do not support IP access control lists (ACLs).

Layer 3 quality of service (QoS) ACLs and other QoS features related to Layer 3 information are not supported on tunnel ports. MAC-based QoS is supported on tunnel ports.

EtherChannel port groups are compatible with tunnel ports as long as the 802.1Q configuration is consistent within an EtherChannel port group.

Port Aggregation Protocol (PAgP), Link Aggregation Control Protocol (LACP), and UniDirectional Link Detection (UDLD) are supported on 802.1Q tunnel ports.

Dynamic Trunking Protocol (DTP) is not compatible with 802.1Q tunneling because you must manually configure asymmetric links with tunnel ports and trunk ports.

Loopback detection is supported on 802.1Q tunnel ports.

When a port is configured as an 802.1Q tunnel port, spanning-tree bridge protocol data unit (BPDU) filtering is automatically enabled on the interface. Cisco Discovery Protocol (CDP) is automatically disabled on the interface.

Configuring an 802.1Q Tunneling Port

Beginning in privileged EXEC mode, follow these steps to configure a port as an 802.1Q tunnel port:

 
Command
Purpose

Step 1 

configure terminal

Enter global configuration mode.

Step 2 

interface interface-id

Enter interface configuration mode and the interface to be configured as a tunnel port. This should be the edge port in the service-provider network that connects to the customer switch. Valid interfaces include physical interfaces and port-channel logical interfaces (port channels 1 to 64).

Step 3 

switchport access vlan vlan-id

Specify the default VLAN, which is used if the interface stops trunking. This is VLAN ID specific to the particular customer.

Step 4 

switchport mode dot1q-tunnel

Set the interface as an 802.1Q tunnel port.

Step 5 

exit

Return to global configuration mode.

Step 6 

vlan dot1q tag native

(Optional) Set the switch to enable tagging of native VLAN packets on all 802.1Q trunk ports. When not set, if a customer VLAN ID is the same as the native VLAN, the trunk port does not apply a metro tag, and packets might be sent to the wrong destination.

Step 7 

end

Return to privileged EXEC mode.

Step 8 

show dot1q-tunnel

Display the tunnel ports on the switch.

Step 9 

show vlan dot1q tag native

Display 802.1Q native VLAN tagging status.

Step 10 

copy running-config startup-config

(Optional) Save your entries in the configuration file.

Use the no switchport mode dot1q-tunnel interface configuration command to return the port to the default state of dynamic desirable. Use the no vlan dot1q tag native global configuration command to disable tagging of native VLAN packets.

This example shows how to configure an interface as a tunnel port, enable tagging of native VLAN packets, and verify the configuration. In this configuration, the VLAN ID for the customer connected to Gigabit Ethernet interface 7 is VLAN 22.

Switch(config)# interface gigabitethernet0/7
Switch(config-if)# switchport access vlan 22
% Access VLAN does not exist. Creating vlan 22
Switch(config-if)# switchport mode dot1q-tunnel
Switch(config-if)# exit
Switch(config)# vlan dot1q tag native
Switch(config)# end
Switch# show dot1q-tunnel interface gigabitethernet0/7
Port
-----
Gi0/1Port
-----	
Switch# show vlan dot1q tag native
dot1q native vlan tagging is enabled

Understanding Layer 2 Protocol Tunneling

Customers at different sites connected across a service-provider network need to run various Layer 2 protocols to scale their topology to include all remote sites, as well as the local sites. STP must run properly, and every VLAN should build a proper spanning tree that includes the local site and all remote sites across the service-provider infrastructure. Cisco Discovery Protocol (CDP) must discover neighboring Cisco devices from local and remote sites. VLAN Trunking Protocol (VTP) must provide consistent VLAN configuration throughout all sites in the customer network.

When protocol tunneling is enabled, edge switches on the inbound side of the service-provider infrastructure encapsulate Layer 2 protocol packets with a special MAC address and send them across the service-provider network. Core switches in the network do not process these packets but forward them as normal packets. Layer 2 protocol data units (PDUs) for CDP, STP, or VTP cross the service-provider infrastructure and are delivered to customer switches on the outbound side of the service-provider network. Identical packets are received by all customer ports on the same VLANs with these results:

Users on each of a customer's sites are able to properly run STP, and every VLAN can build a correct spanning tree based on parameters from all sites and not just from the local site.

CDP discovers and shows information about the other Cisco devices connected through the service-provider network.

VTP provides consistent VLAN configuration throughout the customer network, propagating through the service provider to all switches.

Layer 2 protocol tunneling can be used independently or can enhance 802.1Q tunneling. If protocol tunneling is not enabled on 802.1Q tunneling ports, remote switches at the receiving end of the service-provider network do not receive the PDUs and cannot properly run STP, CDP, and VTP. When protocol tunneling is enabled, Layer 2 protocols within each customer's network are totally separate from those running within the service-provider network. Customer switches on different sites that send traffic through the service-provider network with 802.1Q tunneling achieve complete knowledge of the customer's VLAN. If 802.1Q tunneling is not used, you can still enable Layer 2 protocol tunneling by connecting to the customer switch through access ports and enabling tunneling on the service-provider access port.

For example, in Figure 14-4, Customer A has four switches in the same VLAN that are connected through the service-provider network. If the network does not tunnel PDUs, switches on the far ends of the network cannot properly run STP, CDP, and VTP. For example, STP for a VLAN on a switch in Customer A, Site 1 will build a spanning tree on the switches at that site without considering convergence parameters based on Customer A's switch in Site 2. This could result in the topology shown in Figure 14-5.

Figure 14-4 Layer 2 Protocol Tunneling

Figure 14-5 Virtual Network Topology without BPDU Tunneling

Configuring Layer 2 Protocol Tunneling

You enable Layer 2 protocol tunneling (by protocol) on the access ports or tunnel ports that are connected to the customer in the edge switches of the service-provider network. Edge-switch tunnel ports are connected to customer 802.1Q trunk ports; edge-switch access ports are connected to customer access ports. The Catalyst 3550 switch supports Layer 2 protocol tunneling for CDP, STP, and VTP. The edge switches connected to the customer switch perform the tunneling process.

When the Layer 2 PDUs that entered the inbound edge switch through the tunnel or access port exit the switch through the trunk port into the service-provider network, the switch overwrites the customer PDU-destination MAC address with a well-known Cisco proprietary multicast address (01-00-0c-cd-cd-d0). If 802.1Q tunneling is enabled, packets are also double-tagged; the outer tag is the customer metro tag and the inner tag is the customer VLAN tag. The core switches ignore the inner tags and forward the packet to all trunk ports in the same metro VLAN. The edge switches on the outbound side restore the proper Layer 2 protocol and MAC address information and forward the packets to all tunnel or access ports in the same metro VLAN. Therefore, the Layer 2 PDUs are kept intact and delivered across the service-provider infrastructure to the other side of the customer network.

See Figure 14-4, with Customer A and Customer B in access VLANs 30 and 40, respectively. 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 B 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 outer VLAN tag of 40 as well as an inner VLAN tag (for example, VLAN 100). When the double-tagged packets reach Switch 4, 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 B 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 ports on the customer switch. In this case, the encapsulation and de-encapsulation behavior 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.

This section contains this information about configuring Layer 2 protocol tunneling:

Default Layer 2 Protocol Tunneling Configuration

Layer 2 Protocol Tunneling Configuration Guidelines

Configuring Layer 2 Tunneling Characteristics

Default Layer 2 Protocol Tunneling Configuration

Table 14-1 shows the default Layer 2 protocol tunneling configuration.

Table 14-1 Default Layer 2 Ethernet Interface VLAN Configuration 

Feature
Default Setting

Layer 2 protocol tunneling

Disabled for CDP, STP, and VTP.

Shutdown threshold

No threshold for packets-per-second of Layer 2 PDUs per port for the port to shut down.

Drop threshold

No threshold for packets-per-second of Layer 2 PDUs per port for the port to drop the PDUs.

Class of service (CoS) value

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.


Layer 2 Protocol Tunneling Configuration Guidelines

These are some configuration guidelines and operating characteristics of Layer 2 protocol tunneling:

The switch supports tunneling of CDP, STP, including multiple STP (MSTP), and VTP. Protocol tunneling is disabled by default but can be enabled for the individual protocols on 802.1Q tunnel ports or on access ports.

Tunneling is not supported on trunk ports. If you enter the l2protocol-tunnel interface configuration command on a trunk port, the command is accepted, but Layer 2 tunneling does not take affect unless you change the port to a tunnel port or access port.

EtherChannel port groups are compatible with tunnel ports as long as the 802.1Q configuration is consistent within an EtherChannel port group.

If an encapsulated PDU (with the proprietary destination MAC address) is received from a tunnel port or access port with Layer 2 tunneling enabled, the tunnel port is shut down to prevent loops. The port also shuts down when a configured shutdown threshold for the protocol is reached. You can manually re-enable the port (by entering a shutdown and no shutdown command sequence) or if errdisable recovery is enabled, the operation is retried after a specified time interval.

Only decapsulated PDUs are forwarded to the customer network. The spanning-tree instance running on the service-provider network does not forward BPDUs to tunnel ports. No CDP packets are forwarded from tunnel ports.

When protocol tunneling is enabled on an interface, you can set a per-protocol, per-port, shutdown threshold for the PDUs generated by the customer network. If the limit is exceeded, the port shuts down. You can also rate-limit BPDUs by using QoS ACLs and policy maps on a tunnel port.

When protocol tunneling is enabled on an interface, you can set a per-protocol, per-port, drop threshold for the PDUs generated by the customer network. If the limit is exceeded, the port drops PDUs until the rate at which the port receives them is below the drop threshold.

Because tunneled PDUs (especially STP BPDUs) must be delivered to all remote sites for the customer virtual network to operate properly, you can give PDUs higher priority within the service-provider network than data packets received from the same tunnel port. By default, the PDUs use the same CoS value as data packets.

Configuring Layer 2 Tunneling Characteristics

Beginning in privileged EXEC mode, follow these steps to configure a port for Layer 2 protocol tunneling:

 
Command
Purpose

Step 1 

configure terminal

Enter global configuration mode.

Step 2 

interface interface-id

Enter the interface configuration mode and the interface to be configured as a tunnel port. This should be the edge port in the service-provider network that connects to the customer switch. Valid interfaces include physical interfaces and port-channel logical interfaces (port channels 1 to 64).

Step 3 

switchport mode access
or
switchport mode dot1q-tunnel

Configure the interface as an access port or an 802.1Q tunnel port.

Step 4 

l2protocol-tunnel [cdp | stp | vtp]

Enable protocol tunneling for the desired protocol. If no keyword is entered, tunneling is enabled for all three Layer 2 protocols.

Step 5 

l2protocol-tunnel shutdown-threshold [cdp | stp | vtp] value

(Optional) Configure the threshold in packets per second to be received for encapsulation before the interface shuts down. The port is disabled if the configured threshold is exceeded. If no protocol option is specified, the threshold is applied to each of the tunneled Layer 2 protocol types. The range is 1 to 4096. The default is to have no threshold configured.

Note If you also set a drop threshold on this interface, the shutdown-threshold value must be greater than or equal to the drop-threshold value.

Step 6 

l2protocol-tunnel drop-threshold [cdp | stp | vtp] value

(Optional) Configure the threshold in packets per second to be received for encapsulation before the interface drops packets. The port drops packets if the configured threshold is exceeded. If no protocol option is specified, the threshold is applied to each of the tunneled Layer 2 protocol types. The range is 1 to 4096. The default is to have no threshold configured.

Note If you also set a shutdown threshold on this interface, the drop-threshold value must be less than or equal to the shutdown-threshold value.

Step 7 

exit

Return to global configuration mode.

Step 8 

errdisable recovery cause l2ptguard

(Optional) Configure the recovery mechanism from a Layer 2 maximum rate error so that the interface can be brought out of the disabled state and allowed to try again. You can also set the time interval. Errdisable recovery is disabled by default; when enabled, the default time interval is 300 seconds.

Step 9 

l2protocol-tunnel cos value

(Optional) Configure the CoS value for all tunneled Layer 2 PDUs. The range is 0 to 7; the default is the default CoS value for the interface. If none is configured, the default is 5.

Step 10 

end

Return to privileged EXEC mode.

Step 11 

show l2protocol

Display the Layer 2 tunnel ports on the switch, including the protocols configured, the threshold, and the counters.

Step 12 

copy running-config startup-config

(Optional) Save your entries in the configuration file.

Use the no l2protocol-tunnel [cdp | stp | vtp] interface configuration command to disable protocol tunneling for one of the Layer 2 protocols or for all three of them. Use the no l2protocol-tunnel shutdown-threshold [cdp | stp | vtp] and the no l2protocol-tunnel drop-threshold [cdp | stp | vtp] commands to return the shutdown and drop thresholds to the default settings.

This example shows how to configure Layer 2 protocol tunneling for CDP, STP, and CDP and to verify the configuration.

Switch(config)# interface gigabitethernet0/7
Switch(config-if)# l2protocol-tunnel cdp
Switch(config-if)# l2protocol-tunnel stp
Switch(config-if)# l2protocol-tunnel vtp
Switch(config-if)# l2protocol-tunnel shutdown-threshold 1500
Switch(config-if)# l2protocol-tunnel drop-threshold 1000
Switch(config-if)# exit
Switch(config)# l2protocol-tunnel cos 7
Switch(config)# end
Switch# show l2protocol
COS for Encapsulated Packets: 7

Port    Protocol Shutdown  Drop      Encapsulation Decapsulation Drop
                 Threshold Threshold Counter       Counter       Counter
------- -------- --------- --------- ------------- ------------- -------------
Gi0/7   cdp           1500      1000             0             0             0
        stp           1500      1000             0             0             0
        vtp           1500      1000             0             0             0

Monitoring and Maintaining Tunneling Status

Table 14-2 shows the privileged EXEC commands for monitoring and maintaining 802.1Q and Layer 2 protocol tunneling.

Table 14-2 Commands for Monitoring and Maintaining Tunneling 

Command
Purpose

clear l2protocol-tunnel counters

Clear the protocol counters on Layer 2 protocol tunneling ports.

show dot1q-tunnel

Display 802.1Q tunnel ports on the switch.

show dot1q-tunnel interface interface-id

Verify if a specific interface is a tunnel port.

show l2protocol-tunnel

Display information about Layer 2 protocol tunneling ports.

show errdisable recovery

Verify if the recovery timer from a Layer 2 protocol-tunnel error disable state is enabled.

show l2protocol-tunnel interface interface-id

Display information about a specific Layer 2 protocol tunneling port.

show l2protocol-tunnel summary

Display only Layer 2 protocol summary information.

show vlan dot1q native

Display the status of native VLAN tagging on the switch.


For detailed information about these displays, refer to the command reference for this release.