Lantronix
SM24TBT2DPA and SM24TBT2DPB Web User Guide
3-11.4 EEE
This page provides an overview of Energy Efficient Ethernet information exchanged by LLDP.
By using EEE power savings can be achieved at the expense of traffic latency. This latency occurs due to
that the circuits EEE turn off to save power, need time to boot up before sending traffic over the link. This
time is called "wakeup time". To achieve minimal latency, devices can use LLDP to exchange information
about their respective TX and RX "wakeup time", as a way to agree upon the minimum wakeup time they
need. If your network has no devices with EEE enabled, then the table will show “No LLDP EEE
information found”.
To show LLDP EEE neighbors:
1. Click Monitor, LLDP, and then click EEE to show discover EEE devices.
2. Click Refresh for manual update web screen.
3. Click Auto-refresh for auto-update web screen.
Figure 3-11.4: LLDP Neighbors EEE information
Parameter descriptions:
Local Port:
The port on which LLDP frames are received or transmitted.
Tx Tw:
The link partner’s maximum time that transmit path can hold off sending data after reassertion of
LPI.
Rx Tw:
The link partner’s time that receiver would like the transmitter to hold off to allow time for the
receiver to wake from sleep.
Fallback Receive Tw:
The link partner’s fallback receive Tw. A receiving link partner may inform the
transmitter of an alternate desired Tw_sys_tx. Since a receiving link partner is likely to have discrete levels
for savings, this provides the transmitter with additional information that it may use for a more efficient
allocation. Systems that do not implement this option default the value to be the same as that of the
Receive Tw_sys_tx.
Echo Tx Tw:
The link partner's Echo Tx Tw value. The respective echo values will be defined as the local
link partner’s reflection (echo) of the remote link partners respective values. When a local link partner
receives its echoed values from the remote link partner it can determine whether or not the remote link
partner has received, registered and processed its most recent values. For example, if the local link
partner receives echoed parameters that do not match the values in its local MIB, then the local link
partner infers that the remote link partners request was based on stale information.
Echo Rx Tw:
The link partner's Echo Rx Tw value.
Resolved Tx Tw:
The resolved Tx Tw for this link. Note: NOT the link partner. The resolved value that is
the actual "tx wakeup time” used for this link (based on EEE information exchanged via LLDP).
Resolved Rx Tw:
The resolved Rx Tw for this link. Note: NOT the link partner. The resolved value that is
the actual "tx wakeup time” used for this link (based on EEE information exchanged via LLDP).
EEE in Sync:
Shows whether the switch and the link partner have agreed on wake times.
Red
- Switch and link partner have not agreed on wakeup times.
Green
- Switch and link partner have agreed on wakeup times.