MPLS Network Device LSP and EXP Based Queuing
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Solution Overview
Problem
Existing MPLS network devices lack the capability to determine the scheduling class of an LSP labeled data packet based on both the LSP label and exp value, leading to insufficient differentiated treatment of packets.
Innovation Solution
Implementing a system where network devices use an ingress data structure to map the exp value to a device-internal Class of Service value, which identifies the input queue for enqueuing packets, and an egress data structure to determine the output queue and drop priority based on the exp value, allowing for separate identification of queue groups and classes of service.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If exp-based queuing is used where all labeled packets with the same exp value share the same queue, then device complexity is reduced, but the ability to provide differentiated scheduling behaviors for different LSPs is lost
Solution Approach 1:
The patent segments the queuing mechanism into two distinct components: LSP label-based queue identification and exp value-based scheduling behavior determination. This allows packets to be routed to appropriate queues while maintaining differentiated scheduling within or across queues, resolving the contradiction between simplified exp-based queuing and the need for LSP-specific scheduling differentiation.
Solution Approach 2:
The patent introduces an additional dimension to the queuing system by using the LSP label to identify specific queues while the exp value determines scheduling behavior. This multi-dimensional approach allows simultaneous achievement of simple exp-based classification and LSP-specific scheduling differentiation without increasing overall system complexity.
2Ease of operation
If label-based queuing is used where an LSP can carry traffic from one scheduling class, then scheduling class control is simplified, but the ability to provide differentiated treatments of packets with different exp values is lost
Solution Approach 1:
The patent segments the packet handling process into two independent stages: LSP label processing for queue identification and exp value processing for scheduling behavior determination. This segmentation allows LSP-based scheduling class control to operate independently while preserving exp value-based packet differentiation capabilities within each queue.
Solution Approach 2:
The patent creates a universal queuing framework where queues can serve multiple purposes: they can be identified by LSP labels for routing purposes while simultaneously supporting exp value-based scheduling for packet differentiation. This multi-functionality resolves the contradiction between simplified label-based control and the need for exp value-based differentiation.
3Adaptability or versatility
If both LSP label and exp value are used to determine scheduling class, then packet differentiation is improved, but device complexity increases
Solution Approach 1:
The patent segments the complex task of determining scheduling class into two separate, independent functions: LSP label lookup for queue identification and exp value mapping for scheduling behavior determination. This segmentation reduces device complexity by allowing each function to be implemented independently using simple data structures rather than requiring complex multi-parameter lookup tables.
Solution Approach 2:
The patent transforms the complex multi-dimensional problem of simultaneous label and exp value processing into two separate dimensional operations: first using LSP label to identify the queue dimension, then using exp value to determine scheduling behavior within that queue. This dimensional separation reduces overall system complexity while maintaining full packet differentiation capability.
Data Source
AI summary
A network device receives a label-switched-path (LSP) labeled data packet, maps the LSP labeled data packet to an input queue, maps a data packet in the input queue to an output queue based on a received LSP label value and a received exp label value, and transmits the LSP labeled data packet from the output queue.