[802.3AZ] outstanding items for 10GBASE-T
In preparation for the meeting at Denver, I've summarized the outstanding items for 10GBASE-T below:
1) Format of sleep signal.
The sleep signal is used to signal to the far end of the link that the local transmitter is entering low power idle mode. Proposals so far suggest that the sleep signal is composed of LP_IDLE codewords encoded in LDPC frames. The length of the sleep signal is undefined so far.
2) Format of refresh signal.
The refresh signal could use DSQ/PAM-16 or a reduced level constellation. No proposals have been made to select a constellation for the refresh signal.
Dmitri's presentation (taich_02_0508) gave details on both staggered and non-staggered refresh cycles. We need to select a single refresh mechanism.
Tq and Tr are important parameters that govern adaptation capability and power savings. Mike Grimwood's presentation (grimwood_01_0308) describes experiments conducted to examine the effect of frequency drift on the quiet and refresh times that can be supported. There is no definition on frequency drift or stability in the standard at present, but these may be needed in order to define Tq and Tr, and to guarantee error-free EEE operation.
3) Format of alert signal
The alert signal needs to be a signal which is easily detectable, and allows maximum power savings. No proposals have been made regarding the format of the signal or the time required.
4) Format of wake signal
Is this needed? Recommend deletion if we do not have a reason for it. Since the system wake time encompasses the PHY wake time it is not clear what purpose this signal serves. If needed the proposals so far suggest that this signal is composed of IDLE codewords encoded in LDPC frames. The length of the sleep signal is undefined so far.
5) Determine the range of parameter values supported for Ts, Tr, Tq, Ta, Taw, Tw. Parameters are fixed (Ts, Ta, Taw) or are selected from a small set of values (Tq, Tr). Tw is a system level variable set by a higher level entity. Dmitri's presentation gave suggested values for some of these parameters but there has not been much discussion of these values.
6) Test mode requirements
Add mode to test transmit jitter with slave in EEE mode.
Likely to require some kind of mode to test frequency stability.
7) Autoneg parameter definition