IEEE P802.3bf
Ti
Time
Synchronization
S
h
i ti
Steve Carlson, IEEE P802.3bf Chair
David Law, IEEE 802.3 WG Chair
Marek Hajduczenia, IEEE P802.3bf Chief Editor
This contribution reuses material from law_1_0110.pdf
submitted to the IEEE 802.3bf Interim Meeting, New Orleans, January 2010 and
p _1002_hajduczenia.pdf
j
p
siepon
May 2010
Joint IEEE 802/ITU Workshop
Geneva May 2010
1
IEEE P802.3bf Background
g
• Before the IEEE P802.3bf
P802 3bf TF was formed …
– Work on Ethernet time synchronization started in 2004
within the Residential Ethernet Study Group (RESG
SG) in IEEE 802.3 WG
– RESG determined that the p
project
j
was best suited for
the IEEE 802.1 WG
– IEEE 802.1 WG created the Audio-Video Bridging
Group (802.1 AVB)
– At the time, it was understood that there would be an
802 3 component to support the
802.3
h 802
802.1
1 AVB work
k
May 2010
Joint IEEE 802/ITU Workshop
Geneva May 2010
2
IEEE P802.3bf Background
g
• and where IEEE 802
802.3
3 is now
now…
– Ethernet Support for the IEEE P802.1AS Time
Synchronization Protocol Task Force (IEEE P802.3bf)
started work in January 2010
– IEEE P802.3bf is also commonlyy referenced to as
“Time Sync” for short
– IEEE P802.3bf Draft 0.3 is current as of 2010.05
• draft 0.4 is expected to be released out of May 2010 meeting
– IEEE P802.3bf intends to request Working Group ballot
i JJuly
in
l 2010
• on draft 0.4
• might be updated to 1
1.0
0 to keep numbering consistent …
May 2010
Joint IEEE 802/ITU Workshop
Geneva May 2010
3
IEEE P802.3bf Objectives
j
• Formal objectives:
– Provide an accurate indication of the transmission
and reception initiation times of certain packets as
required to support IEEE P802.1AS.
• Informal objectives:
– Restrict changes to IEEE 802.3 base document
– Provide
P id PHY agnostic
ti solution,
l ti
capable
bl off
supporting existing and future 802.3 PHYs
– Provide
P id open architecture,
hit t
which
hi h can b
be scaled
l d tto
higher data rate PHYs
May 2010
Joint IEEE 802/ITU Workshop
Geneva May 2010
4
IEEE P802.3bf Architecture
MAC Client
MA_DATA.request
MAC Service interface
(Clause 2)
MA__DATA.indicate
DATA.indication
MA
Time Sync Client
(outside scope of 802.3)
Media Access Control
PLS_DATA.request
q
PLS Service interface
(Clause 6)
xMII
TS Service interface
(Clause 90)
PLS_SIGNAL.indication
PLS_DATA.indication
PLS_DATA_VALID.indication
PLS_CARRIER.indication
TS_TX.indication
RX SFD
detect
RS
TX SFD
detect
TS_RX.indication
•Define TSSI
•Define RX SFD detect
•Define TX SFD detect
•PHY p
propagation
p g
delay
y register/MIB
g
•PHY delay variation register/MIB
xMII
May 2010
Joint IEEE 802/ITU Workshop
Geneva May 2010
5
Data
D_C
ONE /
ZERO
Idle
Idle
SFD
Data
Frame from
MAC Control Client
D_C
ONE /
ZERO
MA_DA
ATA
Idle
SFD
Data
TS_TX
.indication
Frame from
MAC Client
D_C
TX xMII
SFD
PLS_DATA
.request
ONE /
ZERO
MA_DATA
MA
DATA
.request
MA_DA
ATA
Service p
primitive generation
g
- downstream
• Frames may be generated by MAC Control Client and not by MAC Client
•
•
May 2010
In that case
case, MA
MA_DATA.request
DATA request is not generated (nothing is passed through
the MAC Service Interface)
TS_TX.indication will be generated nonetheless (there is a frame passed
through the xMII)
Joint IEEE 802/ITU Workshop
Geneva May 2010
6
TI_RX
.indication
Idle
Data
D_C
ONE /
ZERO
Idle
SFD
RX xMII
Data
SFD
ONE /
ZERO
PLS_DATA
.indication
Frame to
MAC Control Client
D_C
Frame to
MAC Client
MA_DATA
MA
DATA
.indication
MA_DA
ATA
Service p
primitive generation
g
- upstream
p
• Frames may be addressed to MAC Control Client and not to MAC Client
•
•
May 2010
In that case
case, MA
MA_DATA.indication
DATA indication is not generated (nothing is passed
through the MAC Service Interface)
TS_RX.indication will be generated nonetheless (there is a frame passed
through the xMII)
Joint IEEE 802/ITU Workshop
Geneva May 2010
7
IEEE 802.3bf applications
pp
• Provides an accurate indication of the
transmission and reception times of all packets
– direct use case in IEEE P802
P802.1AS
1AS
– there is nothing preventing other use cases as well
• TSSI is
i defined
d fi d in
i an abstract
b t t manner and
d it iis nott
bound to a specific PHY / PHY class
• IEEE 1588v2 could also use IEEE P802
P802.3bf
3bf TSSI
interface for support of transparent clocks
May 2010
Joint IEEE 802/ITU Workshop
Geneva May 2010
8
IEEE 802.3bf p
project
j
information
• Primary website
– http://www.ieee802.org/3/bf/
• Public folder
– http://www.ieee802.org/3/bf/public/index.html
http://www ieee802 org/3/bf/public/index html
• Private folder
– http://www.ieee802.org/3/bf/private/
• IEEE 802.3bf PAR
– http://www.ieee802.org/3/bf/P802.3bf.pdf
• IEEE 802.3bf 5 Criteria
– http://www.ieee802.org/3/time_adhoc/P802_3bf_5Criteria_802_3_approved_1109.pdf
• IEEE 802.3bf Objectives
– http://www.ieee802.org/3/time_adhoc/P802_3bf_objective_802_3_approved_1109.pdf
http://www ieee802 org/3/time adhoc/P802 3bf objective 802 3 approved 1109 pdf
• Email reflector
– http://www.ieee802.org/3/bf/reflector.html
May 2010
Joint IEEE 802/ITU Workshop
Geneva May 2010
9
Questions?
Q
ti
?
May 2010
Joint IEEE 802/ITU Workshop
Geneva May 2010
10
Backup
Slides
May 2010
Joint IEEE 802/ITU Workshop
Geneva May 2010
11
Abstract Service Interface
•
Clause 2 MAC Service Interface example
•
MA_DATA
.request(..)
MAC Client output
MA_DATA.request
(MAC Service
interface))
MA_DATA
.request(..)
MA_DATA.request
MA
DATA request ( destination
destination_address,
address source_address,
source address
mac_service_data_unit, frame_check_sequence)
This primitive defines the transfer of data from a MAC client entity to a
single peer entity or multiple peer entities in the case of group addresses.
Clause 6 Physical Signaling (PLS) service Interface example
ZERO
ON
NE
ZERO
ON
NE
ZERO
ON
NE
D_
_C
ON
NE
ZERO
ON
NE
ZERO
ZERO
ZERO
MAC output
PLS DATA.request
PLS_DATA.request
(PLS Service
interface)
ZERO
PLS_DATA.request (OUTPUT_UNIT)
The OUTPUT_UNIT parameter can take on one of three values: ONE,
ZERO or DATA_COMPLETE
ZERO,
DATA COMPLETE and represent a single data bit
bit. The
DATA_COMPLETE value signifies that the Media Access Control
sublayer has no more data to output.
NOTE – The above is only an illustration of the abstract messages
passing
i iinterface
t f
– messages are instantaneous
i t t
May 2010
Joint IEEE 802/ITU Workshop
Geneva May 2010
12
Review of management
g
architecture
Management entity
Higher layers
DATA
LINK
Ethernet SNMP
MAC Control (optional)
IEEE 802.3 scope
PHYSICAL
Other
SNMP MIBs
Clause 30
Objects
MAC
MDC/ MDIO I/F
Reconciliation Sublayer
xMII (Optional)Pervasive access
MDC/MDIO
registers
PHY
MDC/MDIO (Optional) Clause 22
(Clause 45 for 10Gb/s)
MDI/PI
May 2010
Medium
Joint IEEE 802/ITU Workshop
Geneva May 2010
13
MIB,, Registers
g
and Function
Function in PHY needs register
g
access to make it manageable
g
MIB definition
Function
Register definition
May 2010
Joint IEEE 802/ITU Workshop
Geneva May 2010
14
Review of sublayers
y
and interfaces
MAC Client
MA_DATA.request
MA_DATA.indicate
MA_Control.request
MA_Control.indicate
Clause 2
Clause
MAC 31
Control
MA_DATA.request
Clause 2MA_DATA.indicate
Media
ClauseAccess
4
Control
PLS_DATA.request
PLS_SIGNAL.indication
PLS_DATA.indication
PLS_DATA_VALID.indication
PLS_CARRIER.indication
Clause 6
RS
Clause 22/35/46
xMII
May 2010
Joint IEEE 802/ITU Workshop
Geneva May 2010
15