MPLS Label Allocation Using Segmented Spaces
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Solution Overview
Problem
The multi-protocol label switching (MPLS) protocol faces inefficiencies in label allocation as the number of allocated labels increases, leading to deteriorated performance and preventing continued forwarding of packets along an LSP when a signaling protocol module restarts.
Innovation Solution
A method and apparatus for allocating labels in accordance with a set of ranges, allowing for efficient label switching with peers in a network device, using data structures like free-range structures and splay trees to manage label spaces, enabling flexible management of multiple label spaces and reliable restoration of label spaces during client restarts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If labels are allocated from a centralized array of label identifiers, then label allocation is manageable, but label allocation performance deteriorates as the number of allocated labels increases
Solution Approach 1:
The patent segments the centralized label space into multiple distributed label spaces, with each network device maintaining its own label space. This eliminates the need for centralized array traversal by allowing each device to independently manage and allocate labels from its own segmented label space, thereby improving label allocation performance as the network scales.
Solution Approach 2:
The patent introduces a new dimension of label management by using label spaces as a hierarchical layer above individual label identifiers. Instead of flat array traversal, the system navigates through multiple dimensions: first selecting an appropriate label space, then allocating labels within that space. This dimensional approach enables efficient label allocation even as the total number of labels increases.
2Reliability
If labels are allocated from a centralized array, then label allocation is straightforward, but packet forwarding cannot continue along an LSP when a signaling protocol module restarts
Solution Approach 1:
The patent implements preliminary action by pre-establishing multiple label spaces and pre-configuring backup label allocations. When a signaling protocol module restarts, the system can immediately switch to using labels from pre-prepared alternative label spaces, ensuring continuous packet forwarding without waiting for re-allocation. This preliminary preparation of redundant label resources enables fault tolerance.
Solution Approach 2:
The patent changes the parameter of label space availability from static to dynamic. Label spaces can be activated or deactivated based on the operational state of signaling protocol modules. When a module restarts, the system dynamically switches to using labels from different label spaces, maintaining forwarding capability while adapting to changing system conditions.
Data Source
AI summary
Methods and apparatus for processing labels is described. An exemplary method includes allocating labels at a network device in accordance with a set of one or more ranges, and reflecting, in the set of ranges, labels allocated for label switching with peers of the network device. According to an embodiment, the labels and the set of ranges are within a sub-space of a logically partitioned label space, the sub-space being designated to a client.