Hybrid Bridging Node for Incremental VPLS Migration
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Solution Overview
Problem
Provider bridging networks face large MAC address tables due to shared MAC address spaces, leading to potential table overflow as more end stations are added, and upgrading to VPLS or PBB protocols requires costly network-wide upgrades.
Innovation Solution
A hybrid bridging node operates both legacy and upgraded bridging protocols, selectively broadcasting unicast packets to limit MAC address learning and extend the life of legacy nodes by coupling legacy and upgraded sub-networks, using a MAC relay component to manage packet forwarding and address resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the legacy bridging protocol is used to maintain compatibility with existing nodes, then network compatibility and ease of operation are improved, but the MAC address table size grows excessively large leading to table overflow
Solution Approach 1:
The patent segments the bridging network into two distinct domains: a legacy bridging domain using 802.1Q protocols and a PBB domain using 802.1ah protocols. The hybrid node acts as a boundary device that separates these domains, allowing legacy nodes to maintain their MAC address tables without growth from remote end stations, while the PBB domain handles large-scale addressing efficiently.
Solution Approach 2:
The hybrid node serves as an intermediary device between legacy bridging nodes and PBB nodes. It translates and forwards packets between the two protocols, enabling legacy nodes to communicate with PBB nodes without directly learning their MAC addresses, thus preventing MAC address table overflow in legacy nodes.
2Quantity of substance
If the network is upgraded to VPLS or PBB protocols to reduce MAC address table size, then the MAC address table management is improved, but the cost of capital and operating expenditures increases due to network-wide upgrade requirements
Solution Approach 1:
The network is segmented into legacy and upgraded portions, allowing incremental migration. Not all nodes need to be upgraded simultaneously - legacy nodes can coexist with PBB nodes through the hybrid node interface, enabling cost-effective phased upgrades rather than network-wide replacement.
Solution Approach 2:
The hybrid node performs multiple functions: it operates as a legacy bridging node for backward compatibility, as a PBB node for forward compatibility, and as a protocol translator between the two domains. This multi-functionality enables smooth transition without requiring complete network replacement.
3Adaptability or versatility
If MAC address tables are allowed to grow to accommodate more end stations, then network capacity and adaptability are improved, but the device complexity and potential for table overflow increase
Solution Approach 1:
The addressing space is segmented between local MAC addresses (learned by legacy nodes) and remote MAC addresses (handled by PBB nodes). This segmentation allows the network to scale to accommodate more end stations while keeping individual MAC address tables manageable in size.
Data Source
AI summary
A method and apparatus that operates two bridging protocols in a hybrid bridging node is described. The operation of the two bridging protocols in the hybrid node allows for an incremental transition of a provider bridging network from operating a legacy bridging protocol that shares MAC addresses to a bridging network that operates VPLS and/or PBB bridging protocols. The hybrid bridging node selectively broadcasts unicast packets with unknown MAC addresses from the nodes operating VPLS and/or PBB to nodes operating a legacy bridging protocol.