This presentation provides general information on deterministic Ethernet and how circuit-switching can be emulated in packet-switched networks

1. Deterministic Ethernet &
System Integration
Mirko Jakovljevic
products@tttech.com
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2. 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 data
streams)
The determinism is a spectrum!
Ethernet Today
„indeterministic“ „more deterministic“ „very deterministic“ „strictly deterministic“
Strictly deterministic = circuit-switching only?
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3. 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)
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„indeterministic“ „more deterministic“ „very deterministic“ „strictly deterministic“
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4. Deterministic Ethernet
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5. TTEthernet and Determinism
Strict determinism can be defined as full control of
timing/jitter in a system
Synchronous & asynchronous communication via Ethernet
Packet sent
just-in-time
Receiver
knows exact
packet arrival
time
packet
Eth
NIC packet
Eth
T1 NIC
Switch knows
exact packet T1
Switch knows forwarding (M +De
in fi
La imiz ned
exact packet time
forwarding
time ten ed
cy )
Synchronous (TDMA-style) Communication
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6. Extensions & Standard Ethernet
Time-triggered extensions on the top of standard switched
Gigabit-Ethernet
• Startup Application
• Recovery
Layer
• Robust fault-tolerant distributed clock
3-7
Core
TTEthernet
services Time-Triggered Extension
Ethernet IEEE 802.3
Makes Ethernet viable for any critical
embedded system application
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7. TTEthernet Standard
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8. Priority-based
Synchronous
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Asynchronous
Ethernet Traffic (TDM) Traffic
Best-Effort (BE)
Rate-
Ethernet Traffic Constrained
(RC) Traffic
TTEthernet Capabilities
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9. Priority-based
Synchronous
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Asynchronous
Ethernet Traffic (TDM) Traffic
Rate-
Best-Effort (BE) Constrained
Ethernet Traffic
(RC) Traffic
TTEthernet Capabilities
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10. 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
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11. TTEthernet, a Communication Infrastructure
Highlight: Fault Tolerance and
Incorporated Redundancy
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12. www.tttech.com
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