Adaptive Routing via Flow-Control Credits
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Solution Overview
Problem
Existing adaptive routing techniques in communication networks do not effectively utilize link-level flow-control credit notifications to make informed decisions about routing packets, leading to potential congestion and inefficiencies, especially in networks with multiple candidate paths.
Innovation Solution
A method and system that select an egress port for packets based on link-level flow-control credit notifications, considering available credits and congestion grades across candidate ports, without adding signaling overhead, by using existing flow-control mechanisms to make adaptive routing decisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing adaptive routing techniques are used to route packets through communication networks, then routing decisions can be made dynamically, but link-level flow-control credit notifications are not effectively utilized leading to potential congestion and inefficiencies
Solution Approach 1:
The patent implements feedback by utilizing link-level flow-control credit notifications from next-hop network elements to dynamically adjust routing decisions. The network element monitors credit notifications indicating buffer availability at next-hop switches and uses this feedback information to select egress ports, thereby avoiding congested paths and improving network efficiency while maintaining reliability
Solution Approach 2:
The patent applies preliminary action by proactively selecting egress ports based on advance credit notifications received from next-hop network elements. By evaluating credit availability before forwarding packets, the network element can preemptively route packets through paths with sufficient buffer capacity, preventing congestion before it occurs rather than reacting after congestion has developed
2Reliability
If adaptive routing decisions are made without utilizing flow-control credit notifications, then routing complexity is reduced, but congestion in next-hop switches cannot be effectively avoided
Solution Approach 1:
The patent applies universality by making the network element capable of multiple functions: it simultaneously performs standard packet forwarding and uses the same flow-control credit notification mechanism for both link-level flow control and adaptive routing decisions. This multi-functionality allows congestion avoidance without adding separate signaling overhead or complex dedicated routing protocols
Solution Approach 2:
The patent implements self-service by having the network element use its own received credit notifications (originally intended solely for flow control) to automatically make routing decisions. The system serves its own routing needs using information already available from the network protocol, eliminating the need for external routing control mechanisms and reducing overall system complexity
3Productivity
If link-level flow-control credit notifications are used for adaptive routing, then routing decisions consider next-hop congestion, but signaling overhead may increase
Solution Approach 1:
The patent applies universality by making the flow-control credit notification mechanism serve dual purposes: traditional link-level flow control and adaptive routing decisions. By reusing existing credit notifications for both functions simultaneously, the system improves routing decision quality without generating additional signaling traffic or increasing protocol overhead
Solution Approach 2:
The patent implements self-service by having the routing function utilize information (credit notifications) that is already being transmitted by the network protocol for flow control purposes. The routing subsystem serves itself using this existing information infrastructure, extracting additional value from signals that would otherwise be used solely for flow control, thereby avoiding additional signaling overhead
Data Source
AI summary
A method for network communication includes receiving in a network element a packet for forwarding to a destination node. The destination node is reachable via two or more candidate ports of the network element that are connected to respective next-hop network elements. Link-level flow-control credit notifications are received in the network element from the next-hop network elements via the respective candidate ports. An egress port is selected for the packet, from among the candidate ports, based at least on the received link-level flow-control credit notifications. The packet is forwarded toward the destination node over the selected egress port.