mLDP over RSVP Multicast Path for Non-VPN Bandwidth Efficiency
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Solution Overview
Problem
Current IP multicast technologies face limitations in supporting real-time applications like IPTV and streaming media due to bandwidth guarantees and failover restrictions, particularly in non-VPN scenarios where PE devices may not support mLDP, hindering large-scale deployment of P2MP multicast.
Innovation Solution
A method that utilizes mLDP mapping messages to acquire RSVP P2MP LSPs, allocates labels, and generates packet forwarding entries, enabling mLDP over RSVP point-to-multipoint multicast paths without requiring complete mLDP support from all nodes, thus facilitating deployment in non-VPN environments and optimizing bandwidth usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mLDP protocol processing is implemented at PE nodes, then point-to-multipoint multicast can be established, but device complexity increases and deployment becomes difficult when PE devices do not support mLDP
Solution Approach 1:
The patent introduces an intermediary mechanism where the PIM-SM multicast protocol works in conjunction with MPLS label switching. The control plane uses PIM-SM to establish multicast groups and the data plane uses MPLS labels for efficient forwarding, avoiding the need for PE nodes to implement complex mLDP protocol processing while still achieving P2MP multicast functionality
Solution Approach 2:
The patent segments the multicast implementation into control plane functions (handled by PIM-SM) and data plane functions (handled by MPLS label switching). This separation allows PE nodes to avoid implementing the full mLDP protocol stack while still participating in P2MP multicast, reducing device complexity and improving deployability
2Loss of energy
If IP multicast is used for point-to-multipoint transmission, then bandwidth efficiency is improved, but bandwidth guarantee and failover capabilities are insufficient for real-time applications
Solution Approach 1:
The patent creates a composite transmission system that combines IP multicast routing (PIM-SM) with MPLS label switching. The IP multicast layer provides efficient group management and routing, while the MPLS layer provides bandwidth guarantees and failover capabilities through its traffic engineering features, achieving both bandwidth efficiency and reliability for real-time applications
3Adaptability or versatility
If VPN negotiation is performed at the control plane for P2MP multicast, then multicast can be established in VPN scenarios, but protocol complexity increases and forwarding entries require VPN information processing
Solution Approach 1:
The patent makes the PIM-SM protocol universal by enabling it to work in both VPN and non-VPN scenarios through MPLS label switching. The same PIM-SM control plane mechanism handles multicast group management regardless of whether VPN negotiation is needed, while the MPLS data plane adapts to different scenarios, reducing control plane complexity and simplifying forwarding entry generation
Data Source
AI summary
Embodiments of the present invention provide a method for implementing P2MP multicast, a network node, and a system. The method includes: acquiring, by a network-side leaf node, an mLDP label of a downstream user-side leaf node and FEC information from an mLDP mapping message of the downstream user-side leaf node, then sending an mLDP mapping message that includes an mLDP label and the FEC information, to an upstream network-side root node, and generating a forwarding entry; searching for or establishing an RSVP P2MP LSP, allocating a label to the FEC information, and associating a forwarding entry of each network-side leaf node with the label of the FEC information; and sending an mLDP label of the network-side root node and the FEC information to an upstream user-side leaf node, and associating the mLDP label with the RSVP P2MP LSP and the label of the FEC information.