Date created: 10/07/19 08:09:13. Last modified: 10/07/19 08:12:55

Backup Pseudowires

Backup Pseudowires:
When the SAP at PE2 is restored, PE2 updates the new status of the SAP by sending a new label mapping message for the same pseudowire FEC or by sending pseudowire status notification message indicating that the SAP is back up. PE1 then starts a timer and reverts back to the primary at the expiry of the timer. By default, the timer is set to 0, which means PE1 reverts immediately. A special value of the timer (infinity) will mean that PE1 should never revert back to the primary pseudowire...The behavior of the pseudowire redundancy feature is the same if PE1 detects or is notified of a network failure that brought the spoke SDP operational status to DOWN.
Alcatel-Lucent’s routers support the ability to configure multiple secondary standby pseudowire paths. For example, PE1 uses the value of the user configurable precedence parameter associated with each spoke SDP to select the next available pseudowire path after the failure of the current active pseudowire (whether it is the primary or one of the secondary pseudowires). The revertive operation always switches the path of the VLL back to the primary pseudowire though. There is no revertive operation between secondary paths meaning that the path of the VLL will not be switched back to a secondary pseudowire of higher precedence when the latter comes back up again.
Alcatel-Lucent’s routers support the ability for a user-initiated manual switchover of the VLL path to the primary or any of the secondary be supported to divert user traffic in case of a planned outage such as in node upgrade procedures.