Multicast BMAC Header Translation for SPB Network Scalability
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Solution Overview
Problem
Conventional mechanisms for connecting multiple Shortest Path Bridging (SPB) networks result in an unmanageable explosion of multicast forwarding table sizes due to increased forwarding information base (FIB) sizes and additional overhead when using a single flat network or additional transport encapsulation.
Innovation Solution
Implementing multicast Backbone Media Access Control (BMAC) header translations, which involve modifying packet headers by replacing original values with less granular values, specifically swapping or replacing Service Instance Identifiers (I-SID) and nicknames within the headers, to reduce forwarding state in the transport network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single flat SPB network is used to connect multiple SPB networks, then network connectivity is achieved, but the forwarding information base (FIB) size explodes and becomes unmanageable
Solution Approach 1:
The patent divides the forwarding information base into two segments: local FIB maintained by each SPB network (containing only local node information) and remote FIB maintained by border nodes (containing remote network information). This segmentation prevents the exponential growth of FIB size in individual networks while maintaining full connectivity across multiple SPB networks.
2Adaptability or versatility
If additional transport encapsulation is used to connect multiple SPB networks, then network connectivity is achieved, but packet overhead increases
Solution Approach 1:
The patent extracts the network identification function from the packet encapsulation header and places it in the BMAC address field. By using the BMAC address to encode both destination identification and network segment information, the patent eliminates the need for additional transport encapsulation layers, thereby reducing packet overhead while maintaining connectivity across multiple SPB networks.
3Adaptability or versatility
If multiple independently operated SPB networks are connected, then network scalability is improved, but multicast forwarding table size becomes unmanageable
Solution Approach 1:
The patent implements local quality by allowing each SPB network to maintain its own local multicast forwarding table containing only local multicast group information. Border nodes maintain separate remote multicast forwarding tables for each connected network. This localized approach enables each network to scale independently while maintaining multicast functionality across network boundaries.
Data Source
AI summary
A method, apparatus and computer program product for performing multicast Backbone Media Access Channel (BMAC) header transformations is presented. A packet having a header is received at a network node. The header is modified to produce a packet having a modified header by replacing an original value inside the header with a less granular value. The packet having a modified header is forwarded into a transport network.