Per Path Per Link Traffic Accounting in Segment Routing
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Solution Overview
Problem
In segment routing, network devices lack a technique for per-label switched path (LSP) and per-link traffic accounting, as they reuse identifiers for multiple LSPs, making it difficult to distinguish and record packet transfer metrics for each LSP.
Innovation Solution
A network device configures a packet header with identifiers that specify the path and associated devices, allowing other devices to record metrics for each path and manage traffic effectively, thereby facilitating improved traffic management and resource conservation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If network devices reuse identifiers for multiple LSPs, then device complexity is reduced and identifier management is simplified, but the ability to distinguish and record packet transfer metrics for each LSP is lost
Solution Approach 1:
The patent segments the identifier into two distinct parts: a first identifier that identifies the LSP and a second identifier that identifies the link. This segmentation allows the network device to reuse the first identifier across multiple LSPs while still maintaining the ability to distinguish traffic belonging to different LSPs when combined with the second identifier, thus resolving the contradiction between identifier management simplicity and metric recording precision.
2Measurement precision
If network devices use per-LSP and per-link traffic accounting, then traffic management precision is improved, but device complexity and processing overhead increase
Solution Approach 1:
The patent introduces an intermediary mechanism where the network device uses the combination of first and second identifiers as a key to access and update counter values. This intermediary approach allows precise traffic accounting without requiring complex per-LSP processing logic, as the identifier combination naturally routes traffic metrics to the appropriate counters, reducing processing overhead while maintaining accounting precision.
3Adaptability or versatility
If network devices configure detailed path identifiers in packet headers, then traffic management and analytics capability is improved, but packet header size and processing overhead increase
Solution Approach 1:
The patent makes the first identifier universal by using it for both LSP identification in routing decisions and as part of the counter indexing key for traffic accounting. This multi-functionality eliminates the need for separate dedicated identifiers for each purpose, avoiding additional header overhead while maintaining comprehensive traffic management and analytics capabilities.
Data Source
AI summary
A first device may receive a packet that includes information identifying a path through a network. The first device may configure a header of the packet to include a first set of identifiers that identifies the path and the first device via which the packet was received. The first device may configure the header of the packet to include a second set of identifiers that identifies a set of devices associated with the path. The set of devices may be associated with providing the packet via a network. The first device may determine whether a counter associated with the first set of identifiers has been initialized. The first device may modify a value of the counter to record a metric. The first device may provide the packet to a second device. The first device may perform an action related to the packet or based on the value of the counter.