DELL N3000 User Manual

Configuring Data Center Bridging Features

Networks classify and prioritize traffic to provide different service 

characteristics to end user traffic flows. Administrators may wish to guarantee 

or limit bandwidth for certain traffic, ensure lossless behavior for other traffic, 

and control the queue discipline/drop characteristics for best-effort traffic. 

Additionally, it is desirable for a switch to support sharing bandwidth among 

bursty sources while still enabling prioritization of time-sensitive or 

management traffic that requires minimum latency.
Enhanced transmission selection (ETS) provides uniform management for 

sharing bandwidth between congestion managed and traditional classes on a 

single bridged network. Using priority-based processing and weight 

allocations, Traffic Class Groups (TCGs) carrying different types of traffic 

such as LAN, SAN, and management traffic can be configured to provide 

minimum bandwidth guarantees, unused bandwidth sharing, and lossless or 

best-effort transmit characteristics. Dell Networking N4000 switches support 

strict priority and Weighted Deficit Round Robin (WDRR) scheduling with 

up to two lossless traffic classes. WDRR schedules traffic based on average 

bandwidth consumed vs. frame counts.

The normal (default) operation of Dell Networking switches, when 

uncongested, is that packets are scheduled for output in the order in which 

they are received, that is, using FIFO scheduling. The class of service (CoS) 

mechanism enables the administrator to schedule packets for output ahead of 

other packets when the switch is congested, choose which type of packets to 

drop when the switch is congested, and assign a minimum bandwidth 

guarantee to ensure scheduling fairness. These mechanisms operate at the 

CoS queue level; that is, the minimum bandwidth guarantees are made 

across all configured CoS queues.

interface

Display the interface TLV configuration for all interfaces 

or for the specified interface.

interface

Display the interface TLV configuration for all interfaces 

or for the specified interface.