Users Guide

13
Data Center Bridging (DCB)
NOTE:
DCB is not supported when you use 10GBaseT ports for stacking.
Ethernet Enhancements in Data Center Bridging
The following section describes DCB.
The S4820T system supports loading two DCB_Cong les: FCoE_DCB_Cong and iSCSI_DCB_Cong.
These les are located in the root directory ash:/CONFIG_TEMPLATE. After copying the conguration les to the startup cong
and reloading the system.
The device supports the following DCB features:
• Data center bridging exchange protocol (DCBx)
• Priority-based ow control (PFC)
• Enhanced transmission selection (ETS)
To congure PFC, ETS, and DCBx for DCB, refer to Sample DCB Conguration for the CLI congurations.
DCB refers to a set of IEEE Ethernet enhancements that provide data centers with a single, robust, converged network to support
multiple trac types, including local area network (LAN), server, and storage trac. Through network consolidation, DCB results in
reduced operational cost, simplied management, and easy scalability by avoiding the need to deploy separate application-specic
networks.
For example, instead of deploying an Ethernet network for LAN trac, include additional storage area networks (SANs) to ensure
lossless Fibre Channel trac, and a separate InniBand 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 unied 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 dierent devices for several trac types are no longer required.
Data center bridging satises the needs of the following types of data center trac in a unied fabric:
Trac
Description
LAN trac LAN trac consists of many ows that are insensitive to latency requirements, while certain applications,
such as streaming video, are more sensitive to latency. Ethernet functions as a best-eort network that may
drop packets in the 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 LAN trac consists of a large number of ows that are generally insensitive to latency requirements,
while certain applications, such as streaming video, are more sensitive to latency. Ethernet functions as a
best-eort 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.
238
Data Center Bridging (DCB)