Multicast Router Fabric Address Labeling for Bandwidth Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In routers with a large number of line cards, the current method of assigning fabric destination addresses for multicast cells results in significant wasted bandwidth due to supercasting, where packets are sent to non-subscribing line cards, leading to inefficiencies in bandwidth usage and throughput.
Innovation Solution
The solution involves mapping switch fabric destination addresses to labels using a label-to-destination address table (LTDT), calculating random permutation signatures or subset intersection signatures to minimize wasted bandwidth by combining fabric destination addresses, and implementing off-line row clustering methods to optimize the LTDT for reduced bandwidth waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fabric destination addresses are assigned to each line card for multicast routing, then multicast delivery is enabled, but significant bandwidth is wasted due to supercasting packets to non-subscribing line cards
Solution Approach 1:
The patent segments the fabric destination address space by introducing labels that group multiple line cards into clusters. Instead of addressing each line card individually, the system divides the address space into label-based segments that represent groups of destination line cards, enabling efficient multicast delivery while avoiding supercasting to non-subscribing cards.
Solution Approach 2:
The patent adds a new dimension to the addressing scheme by introducing a label field alongside the traditional fabric destination address. This dimensional expansion allows the system to map multiple fabric destination addresses to a single label, creating a hierarchical addressing structure that eliminates bandwidth waste while maintaining reliable multicast delivery.
2Productivity
If the number of line cards in a router is increased to handle more network connections, then network capacity is improved, but the complexity of managing fabric destination addresses increases
Solution Approach 1:
The patent merges multiple fabric destination addresses that map to the same label into a single unified entry in the label-to-destination address table. This consolidation reduces the complexity of managing fabric destination addresses as the number of line cards increases, while still enabling the router to handle a larger number of network connections through efficient address mapping.
Solution Approach 2:
The patent introduces labels as an intermediary layer between the fabric destination address and the line card. This intermediary simplifies address management by providing an intermediate level of abstraction that groups multiple line cards under a single label, reducing the complexity of managing fabric destination addresses in high-capacity routers with many line cards.
3Loss of energy
If random permutation signatures or subset intersection signatures are used to map fabric destination addresses to labels, then bandwidth efficiency is improved by minimizing supercasting, but processing overhead is increased
Solution Approach 1:
The patent performs preliminary actions by pre-computing and storing the mappings between fabric destination addresses and labels in the label-to-destination address table. This preliminary setup enables the system to achieve bandwidth efficiency through minimized supercasting while reducing processing overhead during actual multicast operations, as the signature calculations and mappings are established in advance.
Data Source
AI summary
A method, computer program product, system and apparatus are presented for reducing wasted bandwidth due to supercasting multicast cells through a router switch fabric. In one embodiment of the present invention, signatures of a switch fabric destination address are generated and compared. A signature is an information-rich representation of the fabric destination address that is generated using the fabric destination address. Therefore, supercasting can be minimized by combining fabric destination addresses with like signatures. Aspects of the present invention include generating the signatures using random permutation maps of the set of switch fabric ports or determining intersections of a fabric destination address with a selection of subsets of the switch fabric ports. Signature-based solutions for supercast minimization can be performed in a time-efficient manner and be implemented online, while solutions that can generate a more optimal solution but may take a longer time to perform, such as row-clustering, can be implemented off-line. A further aspect of the invention, incorporates an off-line row-clustering supercast minimization method with an on-line signature-based supercast minimization method.