Segment Routing Header for Simplified Packet Forwarding
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Solution Overview
Problem
Current packet forwarding mechanisms in networks, such as IP routing and MPLS, face inefficiencies due to the complexity of decision processes at network nodes, which can limit overall network performance.
Innovation Solution
Segment routing (SR) is introduced, where nodes create a segment stack using different algorithms to identify segments, allowing packets to be forwarded based on segment IDs rather than traditional IP addresses or labels, enabling faster and simpler forwarding engines without dependence on specific OSI model data link layer technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional IP routing or MPLS label-based forwarding is used, then packet forwarding decisions can be made at network nodes, but the complexity of the decision process limits overall network performance
Solution Approach 1:
The patent segments the forwarding decision process by introducing segment IDs that represent predefined path segments. Instead of making complex decisions at each node about where to forward packets, nodes simply match segment IDs in the packet header against their forwarding tables and forward to the next segment's egress interface. This segmentation of the end-to-end path into manageable segments simplifies per-node decision-making while maintaining overall routing flexibility.
Solution Approach 2:
The patent applies preliminary action by pre-computing and advertising segment IDs and their associated egress interfaces through IGP protocols before actual packet forwarding occurs. The control plane performs path computation and distributes segment routing information in advance, so that the data plane only needs to perform simple matching operations during packet forwarding, eliminating the need for complex real-time decisions at each node.
2Ease of operation
If LDP nodes use labels for packet forwarding, then there is no need to examine packet contents, but this requires MPLS infrastructure and label distribution protocols
Solution Approach 1:
The patent makes segment routing universally applicable by designing it to work over standard IP networks without requiring MPLS infrastructure. Segment IDs are distributed using existing IGP protocols (OSPF or IS-IS), and packets carry segment IDs in their headers using standard IP encapsulation. This allows the simplified forwarding approach to be deployed in pure IP networks, MPLS networks, or hybrid networks, making it more versatile than MPLS while achieving similar forwarding simplicity.
Data Source
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AI summary
An apparatus and method is disclosed for segment routing (SR). In one embodiment, the method includes a node creating a segment stack that identifies one segment calculated using a first algorithm and a second segment calculated using a second, different algorithm. The node then attaches this header to a packet and sends it to another node.