Hi Jeff,
As the author of this maintenance request, I believe I should
provide some clarification on the points you raise.
I am not mistaken looking at Figure 76-8 and 76-7, IDLEs are
inserted by MAC in the absence of data to be transmitted and not by PCS. Data
stream passing through the XGMII is continuous and not bursty in 10G-EPON. It
becomes bursty in PCS after the IDLE deletion function, making space for FEC
parity data to be inserted after FEC is calculated.
As for the IdleCount – per proposed definition, this
variable represents **length of gap between subsequent frames**, expressed in
the unit of octet time and not the number of IDLES inserted by MAC. It
represents the duration of the period between two consecutive transmissions as
observed by the ONU control multiplexer. Please note that even though the MAC
Control does not see IDLEs, neither it does see or know what FEC parity is, yet
we have a variable fecOffset (see 77.2.2.3) which is used to calculate the
position within the FEC codeword at the given moment of time. Definition of
fecOffset and proposed IdleCount are very similar, hence I am not really sure
why it causes confusion.
Sincerely,
Marek Hajduczenia, PhD
ZTE Portugal
Edifício Amoreiras Plaza,
Rua Carlos Alberto da Mota Pinto, nr. 9 - 6 A,
1070-374 Lisbon, Portugal
Office: +351 213 700 090
Fax: + 351 213 813 349
Mobile: +351 961 121 851
Marek
From: owner-stds-802-3-maint@xxxxxxxx
[mailto:owner-stds-802-3-maint@xxxxxxxx] On Behalf Of Jeff Mandin
Sent: 16 March 2010 22:15
To: STDS-802-3-MAINT@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_MAINT] Maintenance TF Web Area Update: Maintenance
Requests and Associated Reports
Wael hello,
I just reviewed request 1220 (thanks for fixing the missing attachment).
Request 1220 identifies a problem in the 10G-EPON MAC (ie.
Multipoint MAC Control does not correctly account for a second laser burst
transmitted in a single grant).
1. Regarding the proposed remedy:
- The revised figure 77-14 defines a variable
"IdleCount". I would note that the MPCP layer is not aware of
the IDLEs per se (as they are inserted by the PCS layer in the absence of data
to transmit).
- Moreover the definition of IdleCount states "this variable
advances by 1 after every 8-bit times". To estimate laser-off time
correctly the variable also needs to take the rate adaptation of the
transmitting PCS into account. This would mean that the
advancement of the variable halts while (fecOffset[1:0] = 0).
2. So with gratitude to the submitter of the maintenance request,
it appears that additional study is needed to determine the
best response to request 1220.
3. As well, I would like to suggest that additional study be
given to the requests 1221 and 1222 - which also deal with clause 77
issues.
PMC-Sierra
From:
owner-stds-802-3-maint@xxxxxxxx [mailto:owner-stds-802-3-maint@xxxxxxxx] On
Behalf Of Wael Diab
Sent: Saturday, March 13, 2010 12:30 PM
To: STDS-802-3-MAINT@xxxxxxxxxxxxxxxxx
Subject: [802.3_MAINT] Maintenance TF Web Area Update: Maintenance
Requests and Associated Reports
I
have updated the Maintenance TF Web area for maintenance requests. This
includes all 5 of the pages with reports and the requests themselves. The information
is current as of the start of this upcoming plenary session.
I
look forward to seeing you in Orlando.
--
Wael William Diab
Technical Director, Broadcom
Vice-Chair, IEEE 802.3 Ethernet Working Group