Routing methods, systems, and computer program products

What is this patent about?

’143 is related to the field of network routing and topology management, specifically addressing the problem of packet loss and latency during the period when a network is converging after a failure. In traditional networks, a topology change—such as a link failure—triggers a global update of routing tables, a process that can take significant time and lead to transient loops or dropped traffic. The background context involves the evolution of the Internet and the need for more efficient path-based addressing to overcome the limitations of standard IP routing.

The underlying idea behind ’143 is to bypass the slow convergence of distributed routing protocols by embedding explicit path information directly into packet headers immediately following a failure. Instead of waiting for every node in the network to update its local forwarding table, the node that first detects the disruption calculates an updated path and encodes it into the packet itself. This ensures that traffic continues to flow toward the destination using a valid route while the rest of the network infrastructure is still synchronizing its internal state.

The claims of ’143 focus on a method and system for detecting a topology change that disrupts an existing path and responding by calculating path information for an updated route. The independent claims specifically cover the use of a segment routing (SR) protocol or similar scoped identifier mechanisms to specify the new path within the packet header. This allows the network to route packets without requiring additional control signaling for each individual packet, effectively using the header as a source-routing instruction that remains valid until the network reaches a post-convergence state.

In practice, the invention utilizes different types of identifiers to define the updated path, such as hop identifiers that point to specific outgoing interfaces or scoped identifiers that are valid within particular network regions. When a node receives a packet, it inspects the header to identify the next segment of the path. If a scoped identifier is used, the node maps the current value to a next value—which may be identical—to maintain the path's integrity as the packet moves through different administrative or technical zones of the network. This mechanism allows for a highly granular level of control over the exact sequence of nodes or interfaces the data traverses.

This approach differentiates itself from prior art by significantly reducing the reliance on global routing table stability. By using path-based protocol addresses and segment routing, the system can specify a deterministic route using fewer identifiers than traditional source routing would require. Furthermore, the use of outside-scope identifiers allows a node to direct traffic toward an entire region or a virtual node without needing to know the specific internal interface details of the destination node, providing a flexible and scalable solution for maintaining connectivity in dynamic, large-scale environments.