Deterministic Ethernet - TTEthernet
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Page 1 Copyright © TTTech Computertechnik AG. All rights reserved. www.tttech.com Deterministic Ethernet & System Integration Mirko Jakovljevic [email protected]
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This presentation provides general information on deterministic Ethernet and how circuit-switching can be emulated in packet-switched networks
Transcript of Deterministic Ethernet - TTEthernet
Page 1Copyright © TTTech Computertechnik AG. All rights reserved. www.tttech.com
Deterministic Ethernet & System Integration
Mirko [email protected]
Page 2Copyright © TTTech Computertechnik AG. All rights reserved. www.tttech.com
Deterministic Ethernet
Deterministic communication in Ethernet?• Ethernet is a packet-switching technology (best-effort communication)
• Can be more or less deterministic (priorities and traffic classes for datastreams)
The determinism is a spectrum!
Strictly deterministic = circuit-switching only?
„indeterministic“ „more deterministic“ „very deterministic“ „strictly deterministic“
Ethernet Today
Page 3Copyright © TTTech Computertechnik AG. All rights reserved. www.tttech.com
More / Very Deterministic
More Deterministic• improved chance high-priority data is delivered within specified time
Very Deterministic• defined end-to-end latency (or frame dropped)• Many trade-offs (latency/jitter vs. bandwidth)• Assumption: overprovisioning (max. 5-15% of bandwidth really used)
„indeterministic“ „more deterministic“ „very deterministic“ „strictly deterministic“
HalfHalf--duplex
duplexEthernet Bus
Ethernet Bus
FullFull--duplex
duplex
Ethernet
Ethernet SwitchSwitch
withwith Prioritized
Prioritizedtraffictraffic
MD + MD +
Shaping
Shaping//Policing
Policing//
Packet Drop,
Packet Drop,
wellwell--understood
understood
traffictraffic profile
profile
TDM TDM over
overEthernet
Ethernet((emulation
emulation of of circuitcircuit
switching
switching))
Page 4Copyright © TTTech Computertechnik AG. All rights reserved. www.tttech.com
Deterministic Ethernet
Page 5Copyright © TTTech Computertechnik AG. All rights reserved. www.tttech.com
TTEthernet and DeterminismStrict determinism can be defined as full control of timing/jitter in a system
Synchronous & asynchronous communication via Ethernet
Synchronous (TDMA-style) Communication
packet
packet
T1T1+Defined
(Minimized)Latency
EthNIC
EthNIC
Packet sent just-in-time
Receiver knows exact packet arrival time
Switch knows exact packet forwarding time
Switch knows exact packet forwarding time
Page 6Copyright © TTTech Computertechnik AG. All rights reserved. www.tttech.com
Extensions & Standard Ethernet
Time-triggered extensions on the top of standard switched Gigabit-Ethernet
• Startup
• Recovery
• Robust fault-tolerant distributed clock
Ethernet IEEE 802.3
CoreTTEthernet
services
Application
Time-Triggered Extension
Layer 3-7
Makes Ethernet viable for any criticalembedded system application
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TTEthernet Standard
Page 8Copyright © TTTech Computertechnik AG. All rights reserved. www.tttech.com Page 8
Sync
hron
ous
(TD
M) T
raffi
c
Rat
e-C
onst
rain
ed
(RC
) Tra
ffic
Bes
t-Effo
rt (B
E)
Ethe
rnet
Tra
ffic
Prio
rity-
base
dA
sync
hron
ous
Ethe
rnet
Tra
ffic
TTEthernet Capabilities
Page 9Copyright © TTTech Computertechnik AG. All rights reserved. www.tttech.com Page 9
Sync
hron
ous
(TD
M) T
raffi
c
Rat
e-C
onst
rain
ed
(RC
) Tra
ffic
Bes
t-Effo
rt (B
E)
Ethe
rnet
Tra
ffic
Prio
rity-
base
dA
sync
hron
ous
Ethe
rnet
Tra
ffic
TTEthernet Capabilities
Page 10Copyright © TTTech Computertechnik AG. All rights reserved. www.tttech.com
Time-Triggered Services in TTEthernet
Time-triggered services (SAE AS6802) add:• Distributed fault-tolerant synchronization
• Continuous time service in case of multiple system faults; no master clock; formally verified
• Synchronous hard real-time communication (audio/video/hard RT controls)
• Robust TDMA-style bandwidth partitioning• Enables parallel low-latency/lossless/hard RT and standard LAN applications in one network
Page 11Copyright © TTTech Computertechnik AG. All rights reserved. www.tttech.com
Highlight: Fault Tolerance and Incorporated Redundancy
TTEthernet, a Communication Infrastructure
TTE
TTE
TTE
TTE
TTE
TTE
TTE
TTE
TTE
TTE
TTE
TTE
TTETTE
TTE
TTE
TTE
TTE
TTE
TTE
TTE
TTE
TTE0TTE
Page 15Copyright © TTTech Computertechnik AG. All rights reserved. www.tttech.com
www.tttech.com
