Configuring Mpls Protection Switching - HP HPE FlexNetwork MSR Router Series Configuration Manual

Configuring MPLS protection switching

Overview
MPLS Protection Switching (PS) provides an end-to-end linear protection mechanism for MPLS TE
tunnels. It associates an MPLS TE tunnel (working tunnel) with another MPLS TE tunnel (protection
tunnel) to form a protection group. When the working tunnel fails, traffic is immediately switched to
the protection tunnel, ensuring continuous traffic forwarding.
Protection switching triggering modes
A failure on the working tunnel triggers a protection switching. Protection switching can also be
triggered by a command or a signal fail indication.
•
Command switching (external switching)—A PS is triggered by an externally configured
switching command, which can define the following switching actions (in the descending order
of priority):
Clear—Clears all configured switching actions.
Lockout of protection—Always uses the working tunnel to forward traffic.
Forced switch—Forces traffic to be switched from the working tunnel to the protection
tunnel.
Manual switch—Manually switches traffic from the working tunnel to the protection tunnel.
If a failure has occurred on the protection tunnel, traffic is not switched.
•
Signal fail switching—A PS is automatically triggered by a signal fail indication. The signaling
can be BFD detection for MPLS TE tunnels or interface state (up/down) detection through link
layer. For more information about configuring BFD for MPLS TE tunnels, see
MPLS OAM."
The following shows the protection switching triggers in the descending order of priority:
•
Clear.
•
Lockout of protection.
•
Forced switch.
•
Signal fail on the protection tunnel—The signaling protocol detected a failure on the
protection tunnel.
•
Signal fail on the working tunnel—The signaling protocol detected a failure on the working
tunnel.
•
Clear signal fail—The signaling protocol detected that the working or protection tunnel has
recovered.
•
Manual switch.
If multiple triggers exist, the one with the highest priority determines the tunnel for traffic forwarding.
Protection switching modes
MPLS PS supports the following protection switching modes:
•
1:1 protection switching—Typically, traffic travels along the working tunnel. When either of
the following events occurs, the ingress node selects the traffic forwarding tunnel (working or
protection tunnel) according to the protection state:
The ingress or egress node detects a failure on the working tunnel.
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