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Layer 2 Control Protocol Transparency for EVPN

Layer 2 Control Protocols (L2CP) are Ethernet control protocols, such as spanning-tree, BPDUs, LACP, pause, and so on. The L2CP Ethernet frames have specific destination MAC addresses. The destination MAC addresses are reserved multicast MAC addresses in the range from 01-80-C2-00-00-00 through 01-80-C2-00-00-0F and from 01-80-C2-00-00-20 through 01-80-C2-00-00-2F.

The Metro Ethernet Forum (MEF) specifies the rules for processing L2CP Ethernet frame when the frames arrive at the L2CP decision point on the user network interface (UNI). The rules provide the mechanism for transparently passing the L2CP frame between a Carrier Ethernet Network and a Subscriber Network. Table 1 lists the actions that can be taken at the L2CP decision point and what transpires on Junos devices.

Table 1: MEF Model of Behavior
MEF Actions Junos Device
Pass Junos devices forwards L2CP frames without processing them when the protocol is not configured on the interface. The frame is treated like a multicast address and sent to all the local and remote CE.
Peer When the protocol is configured on the interface, the Packet Forwarding Engine further processes the frame.
Discard You must explicitly configure a filter on the appropriate physical or logical interface to discard the frame.

When an L2CP frame arrives at the UNI of the ingress PE Junos device, the Packet Forwarding Engine forwards (passes) the L2CP frame unless you configure the protocol on the local physical or logical interface. When a protocol is configured on the interface, the Packet Forwarding Engine further processes (peers) the frame unless you create a filter to drop (discard) it. We support L2CP transparency on EVPN-MPLS and EVPN-VPWS networks.

Benefits of L2CP Transparency

Adopting L2CP transparency promotes the interoperability of equipment between subscriber networks and carrier networks.

MEF Service Definitions

MEF defines Ethernet Private LAN (EP-LAN) as a port-based service that supports all-to-one bundling. This allows multiple VLANs to be mapped into a single Ethernet Virtual Circuit. Ethernet Virtual Private LAN (EVP-LAN) is a VLAN-based service where VLAN ID identifies the traffic. Table 2 lists and maps the MEF service type to the supported EVPN configuration on Junos OS Evolved devices.

Table 2: MEF Service Type
MEF Service Type Junos EVPN Services

EP-LAN

  • EVPN-MPLS with a MAC-VRF instances for VLAN-Bundle service with Ethernet bridge ports.

  • EVPN-MPLS with MAC-VRF instances for VLAN-Based service with Ethernet bridge ports.

  • L2 Basic Switching: default switching instance with Ethernet bridge ports.

  • L2 Basic Switching: virtual switching instance with Ethernet bridge ports.

EVP-LAN

  • EVPN-MPLS E-LAN MAC-VRF VLAN-Based service with Service Provider Style interfaces (vlan-id-list).

  • EVPN-MPLS E-LAN MAC-VRF VLAN-Aware service with Service Provider Style interfaces.

  • EVPN-MPLS E-LAN MAC-VRF VLAN-Aware service with Enterprise Style interfaces (trunk or access interfaces).

  • EVPN-MPLS E-LAN MAC-VRF VLAN-Bundle service with vlan-id-list interfaces.

  • L2 Basic Switching: default switching instance with Service Provider Style interfaces with vlan-id-list.

  • L2 Basic Switching: default switching instance with Enterprise Style interfaces (trunk or access interfaces).

  • L2 Basic Switching: virtual switching instance with Service Provider Style interfaces with vlan-id-list.

  • L2 Basic Switching: virtual switching instance with Enterprise Style interfaces (trunk or access interfaces).

EVPN-MPLS E-LAN Services

Table 3 lists the reserved MAC address, the L2CP assigned to those MAC addresses, and the actions required for EVPN E-LAN services.

Table 3: EVPN MPLS E-LAN Service
Destination MAC Address L2CP Ethertype /Subtype EP-LAN EVP-LAN
01-80-C2-00-00-00

STP

RSTP

MSTP

Pass Peer or Discard
01-80-C2-00-00-01 Pause 0x8808 Peer or Discard Peer or Discard
01-80-C2-00-00-02

LACP

LAMP

0x8809/01

0x8809/02

Peer or Discard Peer or Discard
01-80-C2-00-00-02 Link OAM 0x8809/03 Peer or Discard Peer or Discard
01-80-C2-00-00-02 ESMC 0x8809/0A Peer or Discard Peer or Discard
01-80-C2-00-00-03 802.1X 0x888E Peer or Discard Peer or Discard
01-80-C2-00-00-04 MAC Specific Control Protocols Peer or Discard Peer or Discard
01-80-C2-00-00-05 Reserved Peer or Discard Peer or Discard
01-80-C2-00-00-06 Reserved Peer or Discard Peer or Discard
01-80-C2-00-00-07 E-LMI 0x88EE Peer or Discard Peer or Discard
01-80-C2-00-00-08 Provider Bridge Group Address Peer or Discard Peer or Discard
01-80-C2-00-00-09 Reserved Peer or Discard Peer or Discard
01-80-C2-00-00-0A Reserved Peer or Discard Peer or Discard
01-80-C2-00-00-0B Reserved Pass Peer or Discard
01-80-C2-00-00-0C Reserved Pass Peer or Discard

01-80-C2-00-00-0D

Provider Bridge MVRP Address Pass Peer or Discard
01-80-C2-00-00-0E LLDP 0x88CC Peer or Discard Peer or Discard
01-80-C2-00-00-0E PTP Peer Delay 0x88F7 Peer or Discard Peer or Discard
01-80-C2-00-00-0F Reserved Pass Peer or Discard

01-80-C2-00-00-20 through 01-80-C2-00-00-2F

GARP

GMRP

Pass Pass

Configure a Filter for EVPN MPLS E-LAN Services

Configure a discard filter for EP-LAN or EVP-LAN for EVPN MPLS E-LAN services as follows:

  1. Configure a firewall filter to discard traffic that matches the reserved destination MAC address for family ethernet-switching.

    Note:

    You must configure a firewall filter to match the destination MAC address and ethertype for the following protocol.

    • Pause

    • LACP

    • LAMP

    • Link OAM

    • ESMC

    • 802.1X

    • E-LMI

    • LLDP

    • PTP Peer Delay

  2. Apply the firewall filter to the interface.

The following is the sample firewall filter configuration for discarding the LACP Ethernet frames. The filter is applied to the EP-LAN interface.

EVPN-VPWS E-LINE Service

Table 4 lists the reserved MAC address, L2CP assigned to those MAC addresses, and the actions required for EVPN VPWS (E-LINE) services. MEF allows different actions for some EP-LAN services on EVPN-VPWS and defines the two options for those protocols as Option 1 and Option 2.

Table 4: EVPN-VPWS

Destination MAC Address

L2CP

Ethertype/Subtype

EP-LAN Option 1

EP-LAN Option 2

EVP-LAN

01-80-C2-00-00-00

STP

RSTP

MSTP

Pass Pass Peer or Discard
01-80-C2-00-00-01

Pause

0x8808

Peer or Discard Peer or Discard Peer or Discard
01-80-C2-00-00-02

LACP

LAMP

0x8809/01

0x8809/02

Peer or Discard Pass Peer or Discard
01-80-C2-00-00-02

Link OAM

0x8809/03

Peer or Discard Pass Peer or Discard
01-80-C2-00-00-02

ESMC

0x8809/0A

Peer or Discard Pass Peer or Discard
01-80-C2-00-00-03

802.1X

0x888E

Peer or Discard Pass Peer or Discard
01-80-C2-00-00-04

MAC-specific Control Protocols

Peer or Discard Peer or Discard Peer or Discard
01-80-C2-00-00-05

Reserved

Peer or Discard Peer or Discard Peer or Discard
01-80-C2-00-00-06

Reserved

Peer or Discard Peer or Discard Peer or Discard
01-80-C2-00-00-07

E-LMI

0x88EE

Peer or Discard Pass Peer or Discard
01-80-C2-00-00-08

Provider Bridge Group Address

Peer or Discard Peer or Discard Peer or Discard
01-80-C2-00-00-09

Reserved

Peer or Discard Peer or Discard Peer or Discard
01-80-C2-00-00-0A

Reserved

Peer or Discard Peer or Discard Peer or Discard
01-80-C2-00-00-0B

Reserved

Pass Pass Peer or Discard
01-80-C2-00-00-0C

Reserved

Pass Pass Peer or Discard
01-80-C2-00-00-0D

Provider Bridge MVRP Address

Pass Pass Peer or Discard
01-80-C2-00-00-0E

LLDP

0x88CC

Peer or Discard Pass Peer or Discard
01-80-C2-00-00-0E

PTP Peer Delay

0x88F7

Peer or Discard Pass Peer or Discard
01-80-C2-00-00-0F

Reserved

Pass Pass Peer or Discard
01-80-C2-00-00-20 through 01-80-C2-00-00-2F

GARP

GMRP

Pass Pass Pass

Configure a Filter for EVPN-VPWS Services

Configure a discard filter for EP-LAN (Option 1 or Option 2) or EVP-LAN for EVPN VPWS services as follows:

  1. Configure a firewall filter to discard traffic that matches the reserved destination MAC address for family ccc.

    Note:

    You must configure a firewall filter to match the destination MAC address and ethertype for the following protocol.

    • Pause

    • LACP

    • LAMP

    • Link OAM

    • ESMC

    • 802.1X

    • E-LMI

    • LLDP

    • PTP Peer Delay

  2. Apply the firewall filter to the interface.

The following is the sample firewall filter configuration for discarding provider bridge group address Ethernet frames. The filter is applied to the EP-LAN interface.