IGMP Querier Segmentation for Layer 2 Multicast Efficiency
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Solution Overview
Problem
Conventional IGMP snooping protocols face challenges when extending multicast domains across transport networks with nodes that are not IGMP-aware, leading to inefficient bandwidth usage and operational complexities, particularly in large virtualized environments where implementing IGMP snooping within core devices can cause state explosions or sub-optimal forwarding.
Innovation Solution
The solution involves dividing a single IGMP interface into multiple IGMP domains with separate Queriers elected for each domain, allowing edge nodes to manage IGMP snooping and redistribute sender information using transport network protocols like IS-IS, thereby avoiding the need for IGMP snooping within the transport network core and ensuring efficient traffic delivery across interconnected Service Layer 2 Networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If IGMP snooping is implemented within core transport network devices, then multicast traffic management is improved, but device complexity and state explosion occur
Solution Approach 1:
The patent extracts the IGMP snooping function from core transport network devices and relocates it to edge devices. This removes the complexity and state management burden from core devices while maintaining multicast traffic management capabilities at the network edges where IGMP messages originate and terminate.
Solution Approach 2:
The patent introduces transport network control messages as intermediaries to carry sender information across the transport network. These control messages enable edge devices to share multicast group state information without requiring core devices to implement IGMP snooping, thus avoiding state explosion in the core.
2Reliability
If IGMP snooping is implemented across the entire network, then multicast forwarding is improved, but bandwidth is wasted due to flooding in transport networks
Solution Approach 1:
The patent segments the network into edge devices and core transport devices, applying IGMP snooping only at the edges. This segmentation allows efficient multicast forwarding at edge devices while preventing unnecessary flooding in the core transport network, as edge devices can prune traffic before it enters the transport network.
Solution Approach 2:
The patent applies IGMP snooping functionality locally at edge devices where it is most needed, rather than uniformly across the entire network. This local application of the function optimizes multicast forwarding at the boundaries while avoiding the bandwidth waste that would result from implementing the same functionality throughout the transport core.
3Device complexity
If a single IGMP Querier is used, then protocol simplicity is maintained, but network scalability is limited in large virtualized environments
Solution Approach 1:
The patent segments the IGMP domain into multiple regions, each with its own Querier at the edge device. This segmentation allows the network to scale to large virtualized environments by distributing Querier functions across multiple edge devices, while each individual Querier maintains protocol simplicity.
Data Source
AI summary
Techniques disclosed herein include systems and methods for extending an IGMP broadcast domain (multicast domain) across a transport network without implementing IGMP snooping within the core of the transport network, yet while providing efficient transport within the core of the transport network. Techniques include dividing a single IGMP interface into multiple IGMP domains or sub-domains. A separate Querier is then elected for each IGMP domain using the single IGMP interface. Edge nodes of the transport network can be configured as the multiple IGMP Queriers, and then re-distribute sender information via a separate routing protocol. Requests can then be sent using the transport network control messaging or routing protocol instead of IGMP snoop messages to advertise multicast data streams in between the multiple IGMP domains (across the transport network). Traffic can then delivered efficiently between isolated access networks of a single Service Layer 2 Network.