residential ethernet overview michael johas teener plumblinks [email protected]
TRANSCRIPT
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Digital Home Media Distribution
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What is the problem in Home CE Network?
The lack of standard interface that is all things to all people Firewire/1394 has limited reach (1394c does but has
other issues). Ethernet and Ethernet Switches does not support
isochronous connections Without standard, CE devices needs more connectors,
not fewer. The next generation contents are all digital and
DRM-enabled. ISP needs compatible service class mapping to
home Broadband delivery of the digital contents over
Cable, xDSL, Satellite, needs an interface that guarantees the quality of experience.
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What are the residential challenges? Wiring – distribution Medium
Existing Wiring & Wireless• Phone (old and Cat 5), Coax (CATV), Powerline,
Wireless• HomePNA & Ethernet , MoCA, HomePlug, WiFi & UWB
Regional Differences - Asia, North America, Europe
Cost – zero incremental cost over time Reduce the # of connector types, leverage volume
Configuration Ease – no new configuration. uPnP, intelligent defaults, transparent (to the
user) DRM.
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What are the possible solutions?
Wired Ethernet FE and GE – Works, but if there are no other traffic and
over-provisioned. Residential Ethernet – add isochronous support so that it
works. Firewire/1394a – works, but limited reach. 1394c requires GigE
PHY’s USB – Master/Slave peripheral connection, short reach. Not fit
for multi-point. MoCA – proprietary protocol over RG59 coax – medium-high
cost. HomePlug – proprietary protocol over power line – high cost
Wireless 802.11a/b/g – 802.11e makes it work. Not ready for multiple HD
contents. 802.11n – Sufficient bandwidth, longer reach. Best solution for
wireless. UWB – Suffers from short reach (see 1394/USB). “wireless
1394/USB”Best of the class solutions. The rest are supplementary technologies
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Why Residential Ethernet? Ethernet is already the grand unifier in all other technologies
WiFi, HomePlug, MoCA, HomePNA, all terminate to an Ethernet port.
High-end media devices already has Ethernet. Enable these Ethernet interfaces with synchronous service class
Wired + Wireless solution required. Reliable guaranteed services are only available over wire. All wireless benefits and suffers from coverage
• 802.11n increases range by 2X or more, but
• Its bandwidth affected by interferences (other wireless & the neighbors’) Residential Ethernet MAC, once done, provides all future
Ethernet interface with isochronous services. Ethernet Volume Power over Ethernet Option Ethernet Roadmap (10/100/1000/10G, PoE Plus, MAC Security, etc.)
But Cat 5 is not installed in every home. Residential Ethernet is adoptable to other medium (at higher cost). Good reason that the solution must include wireless option. Much of Asia and new homes in N America do have Cat 5.
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What are CE Technical Challenges?
Audio-Video Sync to multiple devices
Low-latency for interactive Low Cost Plug & Play
really!
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Technical Challenges and Solutions Bounded Jitter (multi-room
Video/Audio sync) End-point synchronization
Bounded Latency (real-time apps). Interactive Voice and Video over IP Audio JAM session Control/Mgmt (channel/volume selection)
Guaranteed session bandwidth QoS/CoS, over-provisioned BW does NOT
do this. IEEE 1394 mechanisms work well and
adoptable to Res Ethernet.
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IEEE 802.3 Residential Ethernet Study Group Status
Call for Interest in July 2004 Overwhelming support for Residential Ethernet
Work• Interest vote result: 30+ companies 80+ individuals
Held two meetings, September and November. Next meeting in January 2004, the week of 23rd.
Study Group Charter is to justify new standard not writing the standard, but Two workable proposals on the table Both would meet the requirements Both are compatible with IEEE 1394 (Firewire)
services. One leverages from commodity Ethernet switches
Link: http://www.ieee802.org/3/re_study
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Proposal 1: Spyder LAN Introduces real-time data distribution
function overlay in Ethernet Switches Looks more like Ethernet Repeater than Switch TDM service similar to IEEE1394 and IEEE 802.3af
EFM’s EPON Synchronous traffic serviced via network admission
control.
DTE
DTE
DTE
DTE
1000BASE-T PHY
1000BASE-T PHY
1000BASE-T PHY
1000BASE-T PHYUTP Links GMII
MACS
And
802.1 D Bridge
Core
SpiderElement
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Proposal 2: Modified Ethernet Switch Introduces real-time traffic queue in Ethernet Switch
Adds time-sync aware scheduler in addition to CoS/QoS aware scheduler.
Backward compatible to any installed Ethernet Switch Small cost adder to Ethernet Switch. Only solution that offers commodity silicon and
adoption upon introduction.
GE/FEMAC
SwitchingDecision
SharedMemoryFrameBuffer
FIFO(retry)
FIFO QueueSched.
datactrl
SyncQueueSched.
GE/FEMAC
GE/FEMAC
GE/FEMAC
GE/FEMAC
GE/FEMAC
GE/FEMAC
GE/FEMAC
Simplified Ethernet Switch Block Diagram
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Common Solutions Clock Synchronization
Adopt 802.1D STP-like master selection (based on MAC & Device Class)
8 KHz clock sync, and 64 bit resolution (like 1394) Link PnP
Adopt 802.3 auto-negotiation. Need to add ResE to the selection code.
Device PnP Adopt 802.1ab LLDP protocol (MAC/Link Discovery
Protocol) as is. Synchronous Control Protocol
Adopt 802.1 GARP (Generic Attribute Registration –widely used for VLAN registration in form of GVRP)
Path BW reservation Multicast/Broadcast group and path control could use
GMRP as is.
Very few new protocols need to be invented!
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Res Ethernet End-Point Model Choose the most compatible interface model to existing
drivers. Sensible to support both models to minimize time to
market.
ResE support at the MAC ResE support above the MAC
Ethernet DriverSynchronous Drivere.g. ResE, 1394
Unified Res Ethernet Driver
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Call for Action Residential Ethernet is a study group,
and will to transition to a task force soon Your participation is appreciated
Will require updates to 802 architecture 802.1D updates for isochronous
routing/admission control Best if updates are useful for 802.11
and 802.15 as well Want to allow all QoS capabilities preserved
as data moves through Ethernet backbone! Need to start working on harmonization
ASAP!
Backup Slides
Many slides and content lifted from Residential Ethernet Study GroupPresentations
Clock Synchronization
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delay
Bursting causes jitter
rx38 kHz
time
tx4
rx21 kHz
rx11 kHz
rx01 kHz
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delay
Bunching causes jitter
time
rx0
time
rx1
time
rx2
time
rx3
time
tx4
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Bridge re-clocking bounds jitter
bridge
… gate
cycleCount
high
low
isochronous
…asynchronous
transmit
receivecycle-stamp(etc.)
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Synchronized reception/presentation
clockA clockB clockC
No long-term drift: clockA, clockB, clockCClock jitter: sub nanosecond (after PLL)
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Synchronization services for client Clock synchronization direction
control From/to network
Clock to network Clock from network
Higher level scheduling of services•Need to know current time to know
when in the future an event can be scheduled
Time stamping of streaming data
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Synchronization in bridge Protocol to select master clock in network
if no bridge, just uses “highest” MAC address Accept clock from port connected to
network master Forward clock to other ports Re-use 802.1 STP precedence to select
clock source.
Admission Control
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Admission controls for client Request channel number
Multicast address to use as DA Release channel number Request bandwidth from path to talker
Bytes/cycle … makes reservation in output queue of talker (and all output queues in path from talker)
Talker address is channel (multicast address) Release bandwidth from path to talker Accept bandwidth request from listener
Bytes/cycle … makes reservation in output queue of self, if no resources, tags request
Respond to bandwidth request from listener Sent to listener that made request
Accept bandwidth response from talker Release local bandwidth reservation
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Admission controls in bridge Allocate channel using GMRP Forward bandwidth requests to
talker if first request respond directly without
forwarding if already routing channel
Forward bandwidth responses to listener
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Isochronous transport Request transmit of isochronous
packet DA, SA, data, cycle “n”
Receive isochronous packet DA, SA, data, cycle “n”
Clock Synchronization
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local offset
add
global
Adjacent-station synchronization
(t1)
local offset
add
global (t4)
(t3)
(t2)
Station A Station B
Timing snapshots
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local offset
add
global
Adjacent-station synchronization
(t1)
local offset
add
global (t4)
(t3)
(t2)
(t1, t4-t2)
(t2, t3-t1)
Station A Station B
Snapshot value distribution
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local offset
add
global
Adjacent-station synchronization
clockDelta = ((t3 – t1) – (t4 – t2)) / 2; cableDelay = ((t3 – t1) + (t4 – t2)) / 2; offsetB = offsetA – clockDelta;
(t1)
local offset
add
global (t4)
(t3)
(t2)
(t1, t4-t2)
(t2, t3-t1)
Station A Station B
Offset value adjustments
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local offset
add
global
Adjacent station synchronization
local offset
add
global
Station A Station B
8 kHz
…
125s
…
clockSync