The Virtual Private LAN Service (VPLS) architecture provides a multipoint ethernet connection using the Multi-Protocol Label Switching (MPLS) transport. This helps connect multiple devices from different geographical locations to the same virtual network. The Multi-Chassis Link Aggregation (MLAG) provides the redundancy technique in the VPLS architecture, making it failsafe multipoint VPLS connectivity. The redundancy in the network traffic is achieved by dual-homing a Customer Edge (CE) device to two Provider Edge (PE) devices.

A single CE is dual-homed to two PEs for redundancy is shown in the following figure:

The Multi-Chassis Link Aggregation (MLAG) Active-Standby for VPLS feature facilitates implementation of the MLAG Active-Standby between the VPLS PE devices. This facilitates Attachment Circuit (AC) redundancy for the dual-homed Customer Edge (CE) device. This means there is one Active link and another Standby link between a CE device and the PE devices. When an Active link fails, the Standby link becomes Active with the MLAG switch, resulting in a change in topology. The change in topology requires a mac-flush in the peer devices for faster convergence. The feature also facilitates forwarding the automatic mac-flush message to all the peer nodes, reducing the convergence time when a link fails.

The above figure shows a VPLS mesh linked to a dual-homed CE connected to PE1 and PE2. The traffic flows from CE to PE3 through the active MLAG PE1, while PE2 remains a standby MLAG. When PE1 experiences a link failure, the standby MLAG becomes active, and traffic flows through the PE2 device to reach the destination PE3. Configuring the mac flush send on mlag switchover command enables MAC flush PDU tx, and PE2 automatically sends the MAC flush message to all the peer nodes PE1, PE3, and PE4 as depicted by the red arrows, which reduces the convergence time.

Consider the following point while configuring this feature:

This feature enhances the reliability of VPLS by providing redundancy using MLAG.

Refer to the MLAG Configuration section in the OcNOS Layer 2 Guide.

This section shows the configuration of the MLAG VPLS.

The following topology shows a VPLS mesh. The traffic is flowing from SW to PE3. PE1 has an MLAG configured as Active and PE2 as Standby. When a link failure occurs between SW and PE1 (the Active MLAG node), the link between SW and PE2 becomes Active.

The following steps show the configuration of the MLAG VPLS with automatic MAC flush capability during the MLAG switchover.

Use the following show commands to verify the configuration.

The MLAG Active-Standby for VPLS introduces the following configuration command.

Use this command to enable the MAC flush PDU tx during the MLAG switchover.

Use the no command to disable the MAC PDU tx flush during the MLAG switchover.

None

Disabled

VPLS mode

Introduced in OcNOS version 6.6.0.

This example shows how to configure mac flush automatically on the peer nodes:

The following command is revised:

The revertive time range is revised from <1-255> to <1-3600>. For more details, refer to switchover type command in the Multi-chassis Link Aggregation Commands chapter in the Layer 2 Guide.

The following provides definitions for key terms or abbreviations and their meanings used throughout this document: