Configuring Y.1731 Functions When an L2VPN Is Connected to an L3VPN

Single-ended frame loss measurement, dual-ended frame loss measurement, one-way frame delay measurement, and two-way frame delay measurement can be configured when an L2VPN is connected to an L3VPN.

Usage Scenario

In Figure 1, an L2VPN is connected to an L3VPN. To collect performance statistics for a link between CE1 and PE3, use the following monitoring functions defined by Y.1731:

Single-ended frame loss measurement
Dual-ended frame loss measurement
One-way frame delay measurement
Two-way frame delay measurement

Figure 1 L2VPN connected to an L3VPN

Pre-configuration Tasks

Before configuring Y.1731 functions when an L2VPN is connected to an L3VPN, complete the following tasks:

Configure an L2VPN to connect to an L3VPN on MEPs.
Configure CFM on MEPs, and set the MEP type to outward-facing.

Single-ended Frame Loss Measurement When an L2VPN Is Connected to an L3VPN: When an L2VPN is connected to an L3VPN, single-ended frame loss measurement is enabled to monitor link quality. This helps prevent CCMs from overloading the network.

Dual-ended Frame Loss Measurement When an L2VPN Is Connected to an L3VPN: When a CFM-enabled L2VPN is connected to an L3VPN, dual-ended frame loss measurement is enabled to collect detailed statistics and monitor link quality.

One-Way Frame Delay Measurement When an L2VPN Is Connected to an L3VPN: One-way frame delay measurement can be configured when CFM is enabled for an L2VPN connected to an L3VPN to monitor link connectivity and an MEP has the time synchronized with that on an RMEP.

Two-Way Frame Delay Measurement When an L2VPN Is Connected to an L3VPN: Two-way frame delay measurement can be configured when CFM is enabled on an L2VPN connected to an L3VPN to monitor link connectivity and a MEP does not have the time synchronized with that on an RMEP.