# RADIUS-Based Packet Mirroring MLPPP Sessions

When you use RADIUS-based packet mirroring on MLPPP traffic, RADIUS authentication and authorization is performed on the individual links. The mirroring-related VSAs are returned with the RADIUS response. For user-initiated mirroring, which starts when the user logs in, a RADIUS response is returned for each successful authentication/authorization. For RADIUS-initiated mirroring of a user who is already logged in, a single RADIUS request is sent for each link.

- If you are mirroring an L2TP session, the packet-mirroring operation is enabled or disabled on a single link that is uniquely identified by the trigger you use (the RADIUS attributes for Acct-Session-ID or User-Name). For tunneled MLPPP, the individual links in the MLPPP bundle are mirrored separately. The packet-mirroring configuration fails if you use the Acct-Multi-Session-ID attribute (RADIUS attribute 50) for the configuration.
- If you are mirroring an IP session, the packet-mirroring operation is enabled or disabled on the MLPPP bundle as a whole. We recommend that you use the Account-Session-ID RADIUS attribute rather than the User-Name attribute as the trigger. Using the Account-Session-ID attribute is more efficient because the JunosE Software creates one secure policy that packet mirroring uses for all links in the MLPPP bundle. If you use the User-Name attribute, a secure policy is created for the first link, then removed and re-created for every other link.