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Gateways in current/future architectures
Main GW functions (Routing, Diagnostic, …)
Main principles of GW’s functionality (SW aspects,
protocol aspects, AUTOSAR aspects)
LIN/CAN/FlexRay 2 Ethernet transport mechanisms
(1722a)
GW performance aspects
Ethernet GW/Switch in future EE architectures
Gateways in current/future architectures
3
Transition from Central Gateway to Backbone Arch
CAN (FD)
LIN
FlexRay
MOST
Ethernet
SW SW
SW
DCU DCU DCU SW SW
Today
Mid-term
Long-term
CGW
CGW
DCU
SW
Central Gateway
Domain Control Unit
Switch
CGW
Characteristics of different GW types*
No. of interfaces No. of GWs per vehicle
Diagnostic interface
Comments
Central GW any no. of LIN/CAN/FR
<= 1 x Increasing no. of itfs.
Local GW 1 x domain bus itf. n x subdomain bus itfs.
>= 0 -
Domain GW 1 x domain bus itf. 1-2 x backbone itf.
>= 0 possible
GW with integrated Switch
any no. of LIN/CAN/FR/Eth
>= 0 possible
* From the EE architecture point of view
Main GW functions (Routing, Diagnostic, …)
6
Routing Features
• Message Routing
• Packet Routing
• Signal Routing (eventually with signal processing)
• Routing with High Priority
• Different sorts of rate adaption between received and transmitted message, e.g.
Periodic & Immediate Transmit On Change (TOC)
• Y Routing
• Diagnostic Routing
7
t
tCycle_S
t
tGDelay
TOC Msg
SOURCE
DESTINATION
New Msg Data
tCycle_D
Other Gateway Functions
• Nominal-actual configuration comparison
• Diagnostic tester
– CAN and Ethernet interface provided
• Flash function
• Message mirroring on diagnostic bus
• Network management
• OEM specific features 8
Components
Configuration
EC
U_
1
EC
U_
2
EC
U_
3
EC
U_
4
……
Nominal 1 1 0 1 …
Actual 1 0 0 1 …
Main principles of GW’s functionality (SW aspects, protocol aspects,
AUTOSAR aspects)
9
State of the Art: Software Gateway in Central Processing Unit (CPU)
CC Hardware
CPU Software
CC Hardware
RBUF
…
bus schedule
SDU Gateway
Signal Gateway
ECU Bus
…
queue schedule
I-PDUs
TBUF In
pu
t Q
ueu
es
Ou
tpu
t Q
ueu
es
PDUs
De-capsulation, Encapsulation
Application Software
CC 1..n
Application Software
CPU (Software)
CC 1..n NIC
CPU Bus
ECU Bus/Interfaces
Automotive Ethernet
Security Signal Gateway SDU
Gateway Tunnel Gateway
Security (Hardware)
Memory
Transport L3/4
Ethernet Bridge
MACSec
Transport
L2 MAC
Security
Source: ETAS
Notes: IL = Interaction Layer according OSEK Comms 3.03 and AUTOSAR; adopts messages/signals to PDUs
Gateway Protocol Stack Overview
external cabling domain
Sensor/Actuator
ECU Gateway
CAN
Phy
Signal
IL
CAN
Phy
FLX
APP
FLX
Signal
IL
APP
CAN Bus
SIGNAL GW
SDU GW
Actuator/Sensor APP
Phy Phy
Discrete FlexRay Bus
Gateway
ECU
Sensor
FlexRay Bus CAN Bus
Actuator
Sensor Actuator
ECU Actuator Senso
r
Phy TP TP L3TP GW
Signal
IL
APP
TP
11
Source: ETAS
AUTOSAR Aspects
• Message Routing performed in the PDU Router
• Signal Routing performed in AUTOSAR COM
• Signal Processing performed in Apps 12
Internet Protocol
Signal GW
Frame GW
App 1 App n … Signal
Process
LIN/CAN/FlexRay 2 Ethernet transport mechanisms (1722a)
Gateway Protocol Stack with 1722 Tunneling
Gateway Gateway
Sensor
CAN Bus
Actuator
ECU Actuato
r Sensor
ECU
Actuator
Sensor
Gateway
FlexRay Bus
ECU
Actuator
Sensor
Sensor
Actuator
external cabling domain
Sensor ECU/Gateway Gateway
CAN
Phy
Signal
IL
CAN
Phy
Signal
IL
CAN*
P1722
802.1Q x 802.3 MAC PHY
APP
PHY PHY
802.3 MAC
802.3 MAC
MAC-Relay 802.1Q x
CAN*
P1722
Signal
IL
802.1Q x 802.3 MAC PHY
APP Sensor
CAN Bus Ethernet
internal
Ethernet
SIGNAL GW
L2TP GW TUNNEL GW
SDU GW TP TP TP L3TP GW
Source: ETAS
1722a Ctrl Stream Data Generic Frame Format
Ethernet header
AVTP control stream data header
Packet info
LIN/CAN/FR message 1*
LIN/CAN/FR message n* …
* only messages of the same type allowed in one frame
1722a FlexRay PDU Format
Source: IEEE 1722a/D3
The FlexRay PDU consists of a control stream PDU and one or more FlexRay messages
1722a CAN PDU Format
Source: IEEE 1722a/D3
The CAN extended PDU consists of a control stream PDU and one or more CAN extended
messages
1722a LIN PDU Format
Source: IEEE 1722a/D3
The LIN PDU consists of a control stream PDU and one or more LIN messages
Optimized Gateway Messages: The transport PDU consists of a control stream
PDU and one or more LIN, CAN, FR messages
ETAS Contribution to IEEE 1722a LIN/CAN/FR PDU Format
Source: ETAS
GW performance aspects
GW performance aspects The routing performance should allow all messages received on several
buses with 100% load to be loss-free transmitted on the destination
interfaces (which are considered to be in ideal condition)
Latency time requirements are strongly OEM specific, e.g.:
OEM1: tlatency < 2 ms
OEM2: tlatency < 500 µs
Toyota’s ultra low latency: 100µs over 5 hops, i.e. 20µs/hop
Startup time (time needed to start communication)
Network A
Network B
GW
RC Buffer
TX Buffer
Delay Transmission Delay Transmission Delay Operation
t network t latency t network t
Msg Msg Msg
Automotive Gateways
Ethernet GW/Switch in future EE architectures
Ethernet GW/Switch in future EE architectures
DCU SW DCU DCU
CAN (FD)
LIN
FlexRay
Ethernet
CGW
DCU
SW
Central Gateway Domain Control Unit Switch
Daisy Chain with optional redundant path
DCU DCU
DCU DCU
Full Meshed redundant Backbone
DCU SW DCU SW DCU
Switched Architecture CGW inspired
Gateway as possible Time Master
•TBD hope to get the permission from an OEM to insert a slide
Page <#> 24
Gateway as convergence device
TRM
BC
MR
DCUR
GW
2
GW
1
Video camera
Ethernet
GWx Gateway + Switch XYZ ECU
Legende:
CAN (FD)
BC
MF
DCUL GW
GW
AFS
Zone oriented architecture makes use of Ethernet backbone (which connects all main areas of the vehicle)
Inside the zone CAN/LIN networks Ethernet AVB ensures data type convergence on
backbone
SML
SMR
Converged data
Converged data