Users Guide

Data Center Bridging (DCB)

On an I/O Aggregator, data center bridging (DCB) features are auto-configured in standalone mode. You

can display information on DCB operation by using show commands.

NOTE: DCB features are not supported on an Aggregator in stacking mode.

Supported Modes

Standalone, Stacking, PMUX, VLT

Ethernet Enhancements in Data Center Bridging

The following section describes DCB.

• The device supports the following DCB features:

– Data center bridging exchange protocol (DCBx)

– Priority-based flow control (PFC)

– Enhanced transmission selection (ETS)

DCB refers to a set of IEEE Ethernet enhancements that provide data centers with a single, robust,

converged network to support multiple traffic types, including local area network (LAN), server, and

storage traffic. Through network consolidation, DCB results in reduced operational cost, simplified

management, and easy scalability by avoiding the need to deploy separate application-specific networks.

For example, instead of deploying an Ethernet network for LAN traffic, additional storage area networks

(SANs) to ensure lossless fibre-channel traffic, and a separate InfiniBand network for high-performance

inter-processor computing within server clusters, only one DCB-enabled network is required in a data

center. The Dell Networking switches that support a unified fabric and consolidate multiple network

infrastructures use a single input/output (I/O) device called a converged network adapter (CNA).

A CNA is a computer input/output device that combines the functionality of a host bus adapter (HBA)

with a network interface controller (NIC). Multiple adapters on different devices for several traffic types

are no longer required.

Data center bridging satisfies the needs of the following types of data center traffic in a unified fabric:

• LAN traffic consists of a large number of flows that are generally insensitive to latency requirements,

while certain applications, such as streaming video, are more sensitive to latency. Ethernet functions

as a best-effort network that may drop packets in case of network congestion. IP networks rely on

transport protocols (for example, TCP) for reliable data transmission with the associated cost of

greater processing overhead and performance impact.

Data Center Bridging (DCB)