Seamless mLDP Transport Over BIER Core via T-LDP Sessions
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Solution Overview
Problem
Conventional IP multicast forwarding requires transit nodes to maintain per-flow state and participate in multicast-specific tree building protocols, which is inefficient, and migrating to Bit Index Explicit Replication (BIER) in network cores while maintaining multipoint Label Distribution Protocol (mLDP) on edge routers poses challenges in seamless integration.
Innovation Solution
Deploying Targeted mLDP (T-mLDP) sessions with new extensions over a BIER core, using Bit Forwarding Egress Router IDs (BFER IDs) to establish full mesh Targeted Label Distribution Protocol (T-LDP) sessions and proxy advertise connected addresses to enable seamless mLDP transport, allowing BIER core integration with minimal configuration overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional IP multicast forwarding is used, then multicast-specific tree building protocols are maintained, but transit nodes require per-flow state which increases device complexity
Solution Approach 1:
The patent segments the network into BIER core routers and mLDP edge routers, allowing the core to use stateless BIER forwarding while edge routers handle mLDP state maintenance. This segmentation resolves the contradiction by separating forwarding simplicity from protocol complexity.
Solution Approach 2:
The patent introduces T-LDP sessions as an intermediary mechanism between mLDP edge routers and BIER core routers. This intermediary allows seamless mLDP transport over BIER core by enabling address advertisement and session establishment without requiring core routers to maintain per-flow state.
2Device complexity
If BIER is deployed in network core, then multicast state in core is reduced, but seamless integration with mLDP on edge routers becomes challenging
Solution Approach 1:
The patent makes BIER core routers dual-capable by enabling them to participate in both BIER forwarding and T-LDP sessions. This multi-functionality allows seamless integration with mLDP edge routers while maintaining stateless BIER forwarding in the core.
Solution Approach 2:
T-LDP sessions serve as an intermediary that bridges mLDP edge routers and BIER core routers, enabling address advertisement and session establishment without requiring core routers to maintain per-flow state, thus achieving seamless integration with minimal configuration overhead.
3Reliability
If mLDP is maintained on edge routers, then multipoint label distribution continues to function, but integration with BIER core requires additional configuration overhead
Solution Approach 1:
The patent enables BIER core routers to self-configure by participating in T-LDP sessions and automatically advertising their addresses to mLDP edge routers. This self-service capability reduces configuration overhead while maintaining reliable mLDP transport over the BIER core.
Data Source
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AI summary
Seamless multipoint label distribution protocol (mLDP) transport over a bit index explicit replication (BIER) core may be provided. First, it may be determined that a first plurality of network devices comprise BIER edge routers. Then, in response to determining that the first plurality of network devices comprise BIER edge routers, a Targeted Label Distribution Protocol (T-LDP) session may be created between a first one of the first plurality of network devices and a second one of the first plurality of network devices. Next, an address of a peer device connected to the second one of the first plurality of network devices may be advertised by the second one of the first plurality of network devices over the T-LDP session.