Congruent Unicast Multicast Paths in Service Provider 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 within a service provider network by modifying the PIM protocol to include multicast tree identifier information during unicast path construction, ensuring congruent paths and eliminating replication issues.
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 extracts the multicast replication function from the ingress PE device by establishing a separate multicast distribution tree through P nodes. The ingress PE only needs to send a single copy of multicast data into the VPLS domain, and the P nodes handle the replication and distribution to multiple egress PEs along the tree structure, thereby relieving the bandwidth burden on the ingress PE trunk.
Solution Approach 2:
The patent introduces P nodes as intermediary devices between the ingress PE and egress PEs for multicast data transmission. These P nodes act as mediators that receive multicast data from the ingress PE, perform replication, and distribute it to multiple egress PEs along the multicast distribution tree, enabling efficient multicast delivery without overloading the ingress PE trunk bandwidth.
2Productivity
If separate multicast routing is implemented, then multicast data can be transmitted efficiently through tree structures, but packet re-ordering occurs when unicast and multicast paths are unaligned
Solution Approach 1:
The patent merges the unicast and multicast path selection mechanisms by using the same IGP cost metrics and routing protocol (PIM) for both unicast tunnel establishment and multicast distribution tree construction. This ensures that both unicast and multicast data packets follow the same aligned paths through the network, preventing packet re-ordering while maintaining efficient multicast transmission.
3Adaptability or versatility
If standard PIM protocol is used for multicast routing, then multicast trees can be established dynamically, but path failures remain undetected due to lack of alignment with unicast paths
Solution Approach 1:
The patent makes the multicast distribution tree serve multiple functions: it is used both for efficient multicast data transmission and for reliable path failure detection. By aligning the multicast tree with unicast paths and using the same routing metrics, the system can leverage existing unicast OAM mechanisms to monitor and detect failures in the multicast path, thereby improving reliability while maintaining dynamic adaptability.
Data Source
AI summary
A mechanism that provides congruent forwarding paths for unicast and multicast data traffic over a service provider core network includes issuing, by a receiver edge node, a request to join a multicast tree structure. A unicast path from the receiver edge node to a source node of the provider network is then established using a special message that contains an identifier. The identifier allows the unicast path through the core network to be aligned with the multicast tree structure. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.