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Provider Backbone
Bridges - Traffic Engineering (PBB-TE)
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A relatively new concept in Carrier Ethernet would be Provider Backbone Bridges - Traffic Engineered (PBB-TE), being standardized by IEEE 802.1Qay. PBB-TE is an extension of the 'Provider Backbone Bridges' standard, where the Ethernet flows are traffic-engineered. While PBB greatly enhanced the scalability of Ethernet, it still lacked the determinism that might be required for critical point-to-point applications. PBB-TE brings in this determinism by disabling MAC address learning and Spanning Tree Protocol, two features that could potentially cause unpredictability in traditional Ethernet. The traffic-engineered paths enable PBB-TE to provide 50-ms protection, making Ethernet truly deterministic just like TDM transport networks based on SDH/SONET principles. PBB-TE enables the creation of point-to-point traffic engineered trunks using existing Ethernet forwarding plane principles, thus ensuring backward compatibility with the large installed base of Ethernet hardware. The point-to-point tunnels built using PBB-TE can be routed based on diversity, resiliency or load-spreading. PBB-TE is largely based on the concept of simplifying Ethernet for use as a transport technology, and is currently undergoing a massive standardization effort.
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