MPLS Entropy Labels for Stable Telemetry and OAM Paths
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Solution Overview
Problem
Existing MPLS networks face issues with Equal-Cost Multipath (ECMP) flip flops due to periodic changes in the MPLS label stack, affecting operations like telemetry and OAM, as altering the label stack changes packet paths.
Innovation Solution
Utilize the entropy label's TTL or TC field to carry flags for monitoring operations like telemetry and OAM without altering the MPLS label stack, ensuring consistent packet paths and compatibility with existing networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the MPLS label stack is altered to trigger monitoring operations like telemetry and OAM, then the monitoring operations can be initiated, but the ECMP path of packets changes periodically causing flip-flop issues
Solution Approach 1:
The patent extracts the monitoring operation trigger functionality from the MPLS label stack by using the Entropy Label instead. This allows the label stack to remain unchanged for forwarding decisions while the entropy label carries the trigger information, separating the monitoring trigger function from the path determination function and eliminating the flip-flop issue
Solution Approach 2:
The Entropy Label is used for multiple purposes: it provides packet coloring for monitoring operations, carries trigger flags for telemetry and OAM, and maintains ECMP path consistency. This multi-functional use of the entropy label eliminates the need to alter the MPLS label stack for monitoring operations
2Extent of automation
If the MPLS label stack is altered to carry monitoring flags, then monitoring operations can be triggered, but additional label allocation is required increasing device complexity
Solution Approach 1:
The patent makes the Entropy Label multi-functional by using it both for packet coloring and for carrying monitoring operation trigger flags. This eliminates the need for additional label allocation and reduces device complexity while maintaining the ability to trigger telemetry and OAM operations
Solution Approach 2:
The patent combines the packet coloring function and the monitoring trigger function into a single Entropy Label structure. By merging these functions, the patent avoids the need for separate label allocations and reduces the overall complexity of the MPLS label stack
Data Source
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AI summary
Techniques are described for utilizing entropy labels of a Multiprotocol Label Switching (MPLS) label stack for performing monitoring operations (e.g., telemetry, performance measurement, OAM, etc.) without altering the MPLS label stack and/or packet path (e.g., ECMP path). The techniques may include determining, by a node of a network, to perform a monitoring operation associated with traffic that is to be sent along a path through the network. In some examples, the node may receive a packet that is to be sent along the path and encapsulate the packet with an MPLS header. The MPLS header may include an entropy label, entropy label indicator, or other label that is capable of carrying a flag indicating the monitoring operation to be performed. The flag may be carried in a TTL field or traffic class field of the label such that the MPLS label stack is not altered to trigger the monitoring operation.