Dell PowerEdge M520 Dell PowerConnect M6220/M6348/M8024/M8024-k CLI Referen - Page 371

15 Ethernet Configuration Commands PowerConnect switches support a variety of configuration options to optimize network operations. Features such as flow-control and jumbo frames are supported along with a variety of commands to display traffic statistics as well as limit the effects of network loops or other network issues. Jumbo frame technology is employed in certain situations to reduce the task load on a server CPU and to transmit large amounts of data efficiently. Jumbo frames technology predominantly appears where certain applications would benefit from using a larger frame size, e.g. Network File System (NFS). The larger frame size eliminates some of the need for fragmentation, leading to greater throughput. The increase in throughput is particularly valuable on data center servers where the larger frame size increases efficiency of the system and allows processing of more requests. The PowerConnect jumbo frames feature extends the standard ethernet MTU (Max Frame Size) from 1518 (1522 with VLAN header) bytes to 9216 bytes. However, any device connecting to the same broadcast domain should support the same or larger MTU. Flow control is a mechanism or protocol used to temporarily suspend transmission of data to a device to avoid overloading the device receive path. PowerConnect switching implements the flow control mechanism defined in IEEE 802.3 Annexes 31A and 31B (formerly IEEE 802.3x). PowerConnect switching is able to transmit a MAC Control frame containing the PAUSE opcode to halt transmission by the device receiving the PAUSE frame whenever internal congestion is detected by the switching fabric. Flow control is enabled by default for all ports. Storm control allows for rate limiting of specific types of packets through the forwarding plane. The administrator can configure the absolute rate in packets-per-second for the Storm control threshold. Each classified packet type (broadcast, multicast, or unicast) can be enabled/disabled per port, and the threshold level at which Storm-Control is active is also configurable perport and per-type (as a percentage of interface speed). Ethernet Configuration Commands 371