Ingress PE Router Label Stacking for Flexible Packet Routing
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Solution Overview
Problem
Conventional packet routing methods in label switching networks fail to efficiently direct specific packet flows to particular destinations without modifying routing policies on egress routers and do not allow for different routing paths for ingress versus egress packet flows, limiting services like URL scrubbing and traffic monitoring.
Innovation Solution
The implementation of label stacking at ingress PE routers to add inner labels to packets, allowing egress routers to route packets directly to specific interfaces based on these labels without examining packet contents, and the use of a route reflector to inform ingress routers which labels to apply to which packet flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If label stacking is implemented at ingress PE routers to add inner labels to packets, then flexible routing of packets to specific interfaces is enabled, but device complexity increases
Solution Approach 1:
The patent implements label stacking by nesting multiple labels within packet headers. An inner label is embedded inside an outer label structure, allowing the packet to carry multiple routing instructions simultaneously. This nesting mechanism enables ingress PE routers to push additional label information without requiring fundamental changes to the packet structure, thereby achieving flexible routing while managing device complexity through a systematic layered approach.
Solution Approach 2:
The patent adds a new dimension to packet routing by introducing inner labels that operate independently from traditional outer labels. This creates a multi-layered labeling system where inner labels provide an additional dimension of routing control, enabling packets to be directed to specific interfaces based on fine-grained label matching without requiring modifications to the core routing infrastructure.
2Productivity
If route reflector is used to inform ingress routers which labels to apply, then targeted packet flow management is achieved, but device complexity increases
Solution Approach 1:
The patent introduces a route reflector as an intermediary component that mediates between ingress PE routers and the label distribution system. The route reflector receives routing information, determines appropriate inner label assignments, and distributes this information to ingress routers. This intermediary approach centralizes the complex label management logic, allowing ingress routers to simply apply labels based on route reflector instructions without implementing complex label management themselves, thereby improving packet flow management efficiency while managing device complexity through specialization.
3Speed
If egress routers route packets based on inner labels without examining packet contents, then routing speed is improved, but routing precision may be reduced
Solution Approach 1:
The patent applies preliminary action by pre-assigning inner labels to packets at the ingress PE router based on detailed routing policy decisions. The ingress router examines packet contents, destination addresses, and routing requirements to determine the appropriate inner label before the packet leaves the ingress router. This preliminary classification ensures that subsequent egress router routing based solely on label matching achieves both high speed and high precision, as the label already encodes the complete routing decision.
Data Source
AI summary
Example methods, apparatus and articles of manufacture to manipulate packet routing are disclosed. A disclosed example method includes receiving a first route advertisement from a first provider edge router, the first route advertisement including next-hop routing information associated with a destination and a label associated with an interface of the first provider edge router; modifying the next-hop routing information to form first modified next-hop routing information, the first modified next-hop routing information to redirect a packet addressed to the destination; and sending a second route advertisement to a second provider edge router, the second route advertisement including the first modified next-hop routing information and the label.