Methods and Systems preventing Make Before Break failures during soft preemption in MPLS

A node in a Multiprotocol Label Switching (MPLS) network configured to prevent Make Before Break (MBB) failures during soft preemption of a lower priority Label Switched Path (LSP), the node comprising:

• a plurality of ports;
• forwarding circuitry configured to forward data between the plurality of ports;
• and
• control circuitry communicatively coupled to the plurality of ports and the forwarding circuitry and configured to
• responsive to a determination the lower priority LSP needs preemption, determine a first route of a higher priority LSP which caused the preemption and bandwidth on the first route,
• determine a second route which is a current route of the lower priority LSP and bandwidth on the second route,
• analyze the first route and the second route to determine one or more excluded interfaces which do not support the lower priority LSP due to the higher priority LSP, and
• cause transmission of a preemption message designating a soft preemption of the lower priority LSP including all of the excluded interfaces therein towards an ingress node along the second route of the lower priority LSP.

A Multiprotocol Label Switching (MPLS) network configured to prevent Make Before Break (MBB) failures during soft preemption of a lower priority Label Switched Path (LSP), the MPLS network comprising:

• a plurality of nodes interconnected by a plurality of links;
• wherein a lower priority LSP is configured over the plurality of links, and, responsive to a reservation for a higher priority LSP, an intermediate node of the plurality of nodes is configured to
• determine a requirement to preempt the lower priority LSP due to the higher priority LSP,
• determine a first route of the higher priority LSP and bandwidth on the first route,
• determine a second route which is a current route of the lower priority LSP and bandwidth on the second route,
• analyze the first route and the second route to determine one or more excluded interfaces which do not support the lower priority LSP due to the higher priority LSP, and
• transmit a preemption message designating a soft preemption of the lower priority LSP including all of the excluded interfaces therein towards an ingress node along the second route.