System information

Publication date: Feb., 2012
Revision A1
- 234 -
Chapter 52 EEECommandsofCLI
EEE
The section which allows the user to inspect and configure the current
EEEportsettings.
EEEisapowersavingoptionthatreducesthepowerusagewhenthereis
verylowtrafficutilization(ornotraffic).
EEE works by powering down circuits when there is no traffic. When a
port gets
 data to be transmittedall circuits are poweredup. The time it
takestopowerupthecircuitsisnamedwakeuptime.Thedefaultwakeup
time is 17 usfor 1Gbitlinksand 30 us for otherlinkspeeds.EEEdevices
mustagreeuponthevalueofthewakeuptime
inordertomakesurethat
both the receiving and transmitting device has all circuits powered up
when traffic is transmitted.Thedevices can exchange informationabout
thedeviceswak euptimeusingtheLLDPprotocol.
Formaximizingthepowersaving,thecircuitisn'tstartedatoncetransmit
dataareready for
a port, but is insteadqueueduntil 3000bytes of data
arereadytobetransmitted.Fornotintroducinga largedelayincasethat
data less then 3000 bytes shall be transmitted, data are always
transmittedafter48us,givingamaximumlatencyof48us+thewakeup
time.
If desired it is possible to minimize the latency for specific frames, by
mappingtheframestoaspecificqueue(donewithQOS),andthenmark
the queue as an urgent queue. When an urgent queue gets data to be
transmitted,thecircuits will bepoweredup at once and
the latency will
bereducedtothewakeuptime.

Table 51: EEE Commands
Command Function
mode
Configure EEE mode
show
Show EEE information
urgent-queue
Configure EEE urgent queue
mode: ThecommandletsyouConfigureEEEmode
Syntax:
mode <port-list> disable
/
enable
Parameter :
<port-list>: available value is from switch physic port density, format:
1,3-5
disable: Disable Energy Efficient Ethernet
enable: Enable Energy Efficient Ethernet