Aligning Unicast Multicast Paths in VPLS Networks
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Solution Overview
Problem
Current VPLS networks face inefficiencies in multicast data transmission due to ingress replication, which exceeds the throughput of ingress PE trunk bandwidth, especially in high-bandwidth applications, and results in packet re-ordering and undetected path failures due to unaligned unicast and multicast paths.
Innovation Solution
Aligning unicast and multicast paths through an algorithm that establishes unicast paths from source to receiver nodes, using trace path messages to capture node information for building congruent multicast distribution trees, ensuring optimal bridging and reducing replication by using PIM protocol with recorded unicast path information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ingress replication is used for multicast data transmission in VPLS networks, then multicast data can be delivered to multiple receiver nodes, but the replication process exceeds the throughput of ingress PE trunk bandwidth in high-bandwidth applications
Solution Approach 1:
The patent segments the multicast data transmission by establishing separate unicast paths from the source PE node to each receiver PE node. Instead of replicating data at the ingress PE node, the data is transmitted along pre-established unicast paths, with each path handling traffic to a specific receiver. This segmentation eliminates the bandwidth bottleneck caused by ingress replication while maintaining efficient multicast delivery.
2Productivity
If separate multicast distribution trees are used, then multicast data can be transmitted efficiently, but packet re-ordering occurs when unicast and multicast paths are not aligned
Solution Approach 1:
The patent merges the unicast and multicast path selection by using the same path computation algorithm for both. The PIM protocol builds multicast distribution trees using the same underlying unicast routing information, ensuring that packets transmitted via unicast paths and multicast paths follow congruent routes through the network. This merging of path selection mechanisms eliminates packet re-ordering while preserving the efficiency benefits of multicast transmission.
3Adaptability or versatility
If unaligned unicast and multicast paths are used, then network flexibility is maintained, but path failures remain undetected
Solution Approach 1:
The patent implements feedback mechanisms through the alignment of unicast and multicast path computation. Since both path types use the same routing information and computation logic, the network gains visibility into the actual paths being used. This alignment enables proper failure detection through standard unicast routing protocols, as they can now monitor the same paths that carry multicast traffic, providing reliable feedback on path status while maintaining network flexibility.
Data Source
AI summary
A provider edge (PE) node of a network operates to send a trace path message over the network to a receiver PE node, the trace path message recording a list of intermediate nodes of a unicast path from the PE node to the receiver PE node; and receive a join message initiated from the receiver PE node, the join message using the list to propagate to the source PE node through the intermediate nodes such that a branch of a multicast tree is aligned with the unicast path. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).