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Data center bridging (DCB) is an enhancement to existing 802.1 bridge specifications standards that involves four technological enhancements. DCB is in development by the IEEE 802.1 Data Center Bridging Task Group. The group’s objective is to create a converged data-center network infrastructure using Ethernet as the unified fabric.
Currently, data centers typically have multiple application-specific networks that run on separate link-layer technologies, such as Fibre Channel (FC) for storage and Ethernet for connecting to a local-area network (LAN). The goal is to enhance Ethernet so it becomes a lossless transport that allows 802.1 bridges to to deploy a single converged network for all data-center applications.
The benefits of a converged data center network include:
- Simpler management with only one fabric to deploy, maintain and upgrade.
- Fewer failure points where networks connect.
- Lower costs because fewer adapters, cables and switches and less power are required to enable communication among disparate networks.
The four specifications from the DCB Task Group are:
Priority-based Flow Control (PFC). Provides a link-level, flow-control mechanism that can be independently controlled for each priority to ensure zero-loss due to converged-network congestion.
Congestion Notification (CN). Provides end-to-end congestion management for protocols without built-in congestion-control mechanisms. It’s also expected to benefit protocols with existing congestion management by providing more timely reactions to network congestion.
Enhanced Transmission Selection (ETS). Provides a common management framework for bandwidth assignment to traffic classes.
Data Center Bridging Exchange Protocol (DCBx). A discovery and capability exchange protocol used to convey capabilities and configurations of the other three DCB features between neighbors to ensure consistent configuration across the network.