US 12,476,906 B2
Label distribution protocol (LDP) convergence in ring topologies
Bindhia Komath, Sunnyvale, CA (US); Muthurajah Sivabalan, Ottawa (CA); Wade Miller, Cheney, WA (US); Tao Wang, Ottawa (CA); and Sami Boutros, Union City, CA (US)
Assigned to Ciena Corporation, Hanover, MD (US)
Filed by Ciena Corporation, Hanover, MD (US)
Filed on Jun. 16, 2022, as Appl. No. 17/841,728.
Prior Publication US 2023/0412500 A1, Dec. 21, 2023
Int. Cl. H04L 45/50 (2022.01); H04B 10/2575 (2013.01); H04B 10/275 (2013.01); H04L 12/46 (2006.01); H04L 45/00 (2022.01); H04L 45/02 (2022.01)
CPC H04L 45/507 (2013.01) [H04L 12/4637 (2013.01); H04L 45/02 (2013.01); H04L 45/22 (2013.01); H04B 10/25755 (2013.01); H04B 10/275 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A node configured to operate in a network utilizing Multiprotocol Label Switching (MPLS), the node comprising circuitry configured to:
perform a convergence procedure to discover the topology of a network in which multiple nodes are arranged, and
upon determining that the topology of the network is a ring topology whereby the node is connected to two neighboring nodes by a respective link,
create a first table associated with a first interface corresponding to a first link, the first table including labels representing at least a portion of a label stack for allowing the node to transmit packets to another node in the network in a clockwise (CW) direction around the ring,
create a second table associated with a second interface corresponding to a second link, the second table including the labels representing at least a portion of a label stack for allowing the node to transmit packets to another node in the network in an anti-clockwise (ACW) direction around the ring, wherein the labels are ingress labels and are the same in both the first table and the second table except pointing in different directions around the ring, and
receive packets on one of the first interface and the second interface, the packets arriving in one of the CW direction and the ACW direction and utilize either the first table or the second table for the received packets, when there are no failures, based on the interface on which the packetsare received.