ZyXEL ES3500-24HP User Guide - Page 265

Green Ethernet

Page 265 highlights

CHAPTER 34 Green Ethernet This chapter shows you how to configure the Switch to reduce the power consumed by switch ports. 34.1 Green Ethernet Overview Green Ethernet reduces switch port power consumption in the following ways. • IEEE 802.3az Energy Efficient Ethernet (EEE) If EEE is enabled, both sides of a link support EEE and there is no traffic, the port enters Low Power Idle (LPI) mode. LPI mode turns off some functions of the physical layer (becomes quiet) to save power. Periodically the port transmits a REFRESH signal to allow the link partner keep the link alive. When there is traffic to be sent, a WAKE signal is sent to the link partner to return the link to active mode. • Auto Power Down Auto Power Down turns off almost all functions of the port's physical layer functions when the link is down, so the port only uses power to check for a link up pulse from the link partner. After the link up pulse is detected, the port wakes up from Auto Power Down and operates normally. • Short Reach Traditional Ethernet transmits all data with enough power to reach the maximum cable length. Shorter cables lose less power, so Short Reach saves power by adjusting the transmit power of each port according to the length of cable attached to that port. Note: The ES3500-8PD supports Green Ethernet completely. Note: The ES3500-24 only supports EEE. ES3500 Series User's Guide 265

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ES3500 Series User’s Guide
265
C
HAPTER
34
Green Ethernet
This chapter shows you how to configure the Switch to reduce the power consumed by switch ports.
34.1
Green Ethernet Overview
Green Ethernet reduces switch port power consumption in the following ways.
IEEE 802.3az Energy Efficient Ethernet (EEE)
If EEE is enabled, both sides of a link support EEE and there is no traffic, the port enters Low
Power Idle (LPI) mode. LPI mode turns off some functions of the physical layer (becomes quiet)
to save power. Periodically the port transmits a REFRESH signal to allow the link partner keep the
link alive. When there is traffic to be sent, a WAKE signal is sent to the link partner to return the
link to active mode.
Auto Power Down
Auto Power Down
turns off almost all functions of the port’s physical layer functions when the
link is down, so the port only uses power to check for a link up pulse from the link partner. After
the link up pulse is detected, the port wakes up from
Auto Power Down
and operates normally.
Short Reach
Traditional Ethernet transmits all data with enough power to reach the maximum cable length.
Shorter cables lose less power, so
Short Reach
saves power by adjusting the transmit power of
each port according to the length of cable attached to that port.
Note: The ES3500-8PD supports Green Ethernet completely.
Note: The ES3500-24 only supports EEE.