Dell PowerConnect 5548 User Guide - Page 16

• IP Gateways • PDAs • Audio and video remote monitoring For more information, see "Power over Ethernet" on page 157. Green Ethernet Green Ethernet, also known as Energy Efficient Ethernet (EEE), is an effort to make networking equipment environmentally friendly, by reducing the power usage of Ethernet connections. The Short-Reach method, which reduces power over Ethernet cables shorter than 40m, is supported by the device. For more information, see "Green Ethernet Configuration" on page 384. Head of Line Blocking Prevention Head of Line (HOL) blocking results in traffic delays and frame loss caused by traffic competing for the same egress port resources. To prevent HOL blocking, the device queues packets, and packets at the head of the queue are forwarded before packets at the end of the queue. Flow Control Support (IEEE 802.3X) Flow control enables lower-speed devices to communicate with higher-speed devices, by requesting that the higher-speed device refrain from sending packets. Transmissions are temporarily halted to prevent buffer overflows. For more information, see "Flow Control" on page 380. Back Pressure Support On half-duplex links, the receiving port prevents buffer overflows by occupying the link so that it is unavailable for additional traffic. For more information, see "Protected Ports" on page 388. 16 Dell PowerConnect 55xx Systems User Guide