Configuring L2CP Tunneling

Overview

L2CP Tunneling over an Ethernet Line (ELINE) service allows Layer 2 Control Protocol (L2CP) messages to be tunneled across an ELINE service. This is useful in scenarios where L2CP messages must be transported across an ELINE service, such as when connecting two switches in different locations. Simply put, L2CP tunneling helps initiate control frames from a local (customer-edge) CE device to a remote CE device.

Layer 2 Control Protocols (L2CP) are various Ethernet control protocols such as LACP, STP, and LLDP.

The Ethernet control protocols that can be tunneled are:

• Dot1x
• ECFM
• ELMI
• GMRP
• GVRP
• IGMP
• LACP
• LLDP
• MMRP
• MVRP
• STP

L2CP Frames have specific MAC DAs belonging to reserved multicast MAC address ranges. Several L2CPs have their own MAC DA assigned to them. For example, the MAC DA 01-80-C2 00-00-07 is reserved for E-LMI.

Other protocols share a MAC DA. For example, the address 01-80-C2-00-00-02 is allocated for all “slow protocols” like LACP. Most use untagged frames.

Identifying a specific protocol can be accomplished using:

• MAC DA
• Ether_type
• Slow protocol sub-type

Configurations

Tunneling Action Configuration

Follow the example procedure below to configure L2CP Tunneling over an ELINE service on Skylight Flex.

To configure L2CP Tunneling over an ELINE service

1. Create an ELINE service as seen in the following example (untagged → 2 tags):

c t
shut spanning-tree

int ex 0/1
no sh
exit

int xl 0/1
no sh
end

c t
int ex 0/1
bridge port-type customerEdgePort
end

c t
int xl 0/1
bridge port-type providerNetworkPort
end

c t
vlan 10
ports xl 0/1 ex 0/1 untagged ex 0/1
end

configure terminal
interface ex 0/1
switchport customer-vlan 100 service-vlan 10 
switchport dot1q customer vlan 100
end

2. Configure 802.1p priority with a value between 0 and 7. The frames should exit the ELINE with the configured CoS priority.

l2protocol-tunnel cos 6

3. Configure the ELINE service to use the L2CP Tunneling feature by entering the following command:

c t
int ex 0/1
l2protocol-tunnel gvrp
l2protocol-tunnel override enable 
end

This command enables L2CP Tunneling for GVRP messages.

The command “l2protocol-tunnel override enable” is only needed for VLAN-aware protocols such as GVRP, GMRP, MVRP, MMRP, and ECFM because otherwise the MAC swapping will not be performed.

4. Verify that L2CP Tunneling is working by entering the following command:

show l2protocol-tunnel interface extreme-ethernet 0/1

The output will appear as:

Switch default

COS for Encapsulated Packet : 6

Port  Protocol  Encapsulation Counter  Decapsulation Counter 
 ----  --------  ---------------------  --------------------- 
 Ex0/1     GVRP       100                 0

This command displays the L2CP Tunneling configuration and statistics for the ELINE service.

Discard action configuration

When the Discard action is configured, the frames are dropped at the UNI port and are not sent over the ELINE. Commands seen in the following example can be used to configure the L2CP discard action after setting up an ELINE.

To configure the L2CP discard action after setting up an ELINE

1. Configure the L2CP Discard action on the UNI interface by entering the following command:

c t
int ex 0/1
l2protocol-discard gvrp
l2protocol-tunnel override enable 
end

This command enables L2CP Discard for GVRP messages.

The command “l2protocol-tunnel override enable” is only needed for VLAN-aware protocols such as GVRP, GMRP, MVRP, MMRP, and ECFM because otherwise the MAC swapping will not be performed.

2. Verify that L2CP Discard is working by entering the following command:

sh l2protocol-discard statistics  interface extreme-ethernet 0/1

The output will appear as:

Switch default
 Port Ex0/1 
------------
 Protocol  Discard-Counter:Rx   Discard-Counter:Tx 
 --------  ------------------   ------------------- 
   GVRP          100                     0

This command displays the L2CP Discard configuration and statistics for the ELINE service.

Peer Action Configuration

When the Peer action is configured, Skylight Flex will act as a peer with the CE device and participate in the control protocol negotiation with its peer. The control frames coming to the UNI in this case will be interpreted and not tunneled over the ELINE.

To configure the peer action

1. Execute the following command on the UNI interface:

c t
int ex 0/1
l2protocol-peer lldp
end 

Checking Tunnel Status

To display tunnel status

1. Check if tunneling was properly configured using the following command:

sh l2protocol-tunnel summary

The output will appear as:

Switch default

COS for Encapsulated Packet : 7

 Port  Protocol  Status
----  --------  ------
 Ex0/1    IGMP     down

Checking Configured Tunnel MAC Addresses

The tunnel MAC address is the destination MAC address that will be added to the control frames during the L2CP tunneling over the ELINE. The frames ingress the ELINE with their defined Multicast MAC address as the destination and, during the tunneling, the multicast address will be swapped by the tunnel MAC address.

The configured tunnel MAC address for each control protocol can be verified.

To display the list of configured tunnel MAC addresses

1. Use the following command:

sh l2protocol tunnel-mac-address

The output will appear as:

Switch default
 VLAN tunnel MAC address  
--------------------------
 Dot1x tunnel MAC address :  01:00:0c:cd:cd:d3    
 LACP  tunnel MAC address :  01:00:0c:cd:cd:d4    
  STP  tunnel MAC address :  01:00:0c:cd:cd:d0    
 MVRP  tunnel MAC address :  01:00:0c:cd:cd:d5    
 MMRP  tunnel MAC address :  01:00:0c:cd:cd:d6    
 GVRP  tunnel MAC address :  01:00:0c:cd:cd:d1    
 GMRP  tunnel MAC address :  01:00:0c:cd:cd:d2    
 ELMI  tunnel MAC address :  01:00:0c:cd:cd:d7    
 LLDP  tunnel MAC address :  01:00:0c:cd:cd:d8    
 ECFM  tunnel MAC address :  01:00:0c:cd:cd:d9    
 EOAM  tunnel MAC address :  01:00:0c:cd:cd:da    
 IGMP  tunnel MAC address :  01:00:0c:cd:cd:db