1. Plant-wide Benefits of EtherNet/IP Seminar
Networking Design Considerations for Real-Time EtherNet/IP Performance - QoS
Plant-wide Benefits of EtherNet/IP Seminar

2. Industrial Traffic Prioritization Network Technology Convergence
Not all traffic is created equal!
Control (e.g., CIP)
Video
Data (Best Effort)
Voice
Bandwidth
Low to Moderate
Moderate to High
Random Drop Sensitivity
High
Low
Latency Sensitivity
Jitter Sensitivity
Not all network traffic is created equal, nor should users treat it equally. To minimize application latency and jitter, control data should have priority within the Cell/Area Zone. Quality of Service (QoS) gives preferential treatment to some network traffic at the expense of others. Control data is more sensitive to latency and jitter than information data.
CIP – Common Industrial Protocol
SMTP – Simple Mail Transfer Protocol
Plant-wide / site-wide networks must prioritize industrial automation and control system (IACS) traffic (CIP) over other traffic types (HTTP, SMTP, etc.) to ensure deterministic data flows with low latency and low jitter
Different industrial traffic types (HMI, I/O, Safety, Motion) have different requirements for latency, packet loss and jitter

3. Industrial Traffic Prioritization Quality of Service (QoS)
QoS helps mitigate the following network issues:
End-to-end delay
Fixed delay – latency
Variable delay – jitter
Bandwidth capacity issues
Packet loss
QoS design considerations:
QoS prioritizes traffic into different service levels
Provides preferential forwarding treatment to some data traffic, at the expense of others
Allows for predictable service for different applications and traffic types
To minimize latency and jitter, users should apply QoS to control data within the Cell/Area Zone. Before implementing QoS within the Industrial Zone, use a multidiscipline team of operations, engineering, IT and safety professionals to establish a QoS policy for the Industrial Zone. This policy should support the needs of operations, including what to apply QoS to and when. Additionally, the multidiscipline team should understand that this policy may differ from the enterprise QoS policy. Enterprise QoS policies commonly give priority to VoIP.
QoS does not increase bandwidth … QoS gives preferential treatment to some network traffic at the expense of others
A traditional network is best-effort
All traffic get the same service, i.e. the forwarding behavior by a network device is FIFO
QoS prioritizes traffic into different service levels and provides preferential forwarding treatment to some data traffic at the expense of lower priority traffic
QoS = Preferential treatment

4. Industrial Traffic Prioritization Quality of Service (QoS)
INGRESS ACTIONS
EGRESS ACTIONS
Queue/
Schedule
Congestion
Control
Classification
Policing/
Metering
Marking
Distinguish Traffic by examining Layer 2/3/4 labels and QoS fields.
QoS changed depending on trust state at port.
Ensure conformance
to a specified rate
DSCP-CoS or CoS-DSCP mapping
4 queues/port with
Priority scheduling
QoS classification based on Layer attributes:
Layer 2 Destination MAC Address
Layer 2 EtherType
Layer 3 Source / Destination IP Address
Layer 4 TCP / UDP Source or Destination Port Number
ODVA EtherNet/IP QoS Specification
Layer 2 … Class of Service (CoS) … 802.1Q/p
Layer 3 … type of service (ToS) … DiffServ Code Point (DSCP)

5. Industrial Traffic Prioritization QoS - Operations
Post-Queuing Operations
Classification and Marking
Queuing and (Selective) Dropping

6. Industrial Traffic Prioritization QoS – Layer 2 CoS
Pre
SFD DA SA
TAG
4 Bytes
Type/Len
Data (Payload)
FCS
802.1Q/p Header
PRI
VLAN ID
CFI
Tagged Ethernet Frame
Three Bits Used for CoS
(802.1p User Priority)
IEEE 802.1Q defines frame format
IEEE 802.1p, also referred to as Class of Service (CoS), defines user priority in 802.1Q frames
Different types of traffic are assigned different CoS values. Only three bits are available for 802.1p marking. Therefore, only 8 classes of service (0-7) can be marked on Layer 2 Ethernet frames.
Challenges with tagged frames
Some IACS devices don’t support – dropped frames
802.1Q/p Class of Service—Ethernet frames can be marked at Layer 2 with their relative importance by setting the 802.1p User Priority bits of the 802.1Q header. Only three bits are available for 802.1p marking. Therefore, only 8 classes of service (0-7) can be marked on Layer 2 Ethernet frames.

7. DiffServ Code Point (DSCP)
Industrial Traffic Prioritization QoS – Layer 3 DiffServ Code Point (DSCP) 7 6 5 4 3 2 1 ID
Offset
TTL
Proto
FCS
IP SA
IP DA
Data
Len
Version Length
ToS
Byte
DiffServ Code Point (DSCP)
IP ECN
IPv4 Packet
IP Precedence
Unused
Standard IPv4
DiffServ Extensions
Differentiated Services (DiffServ) is a model for specifying the relative priority of traffic based on the Type of Service (TOS) field within the IPv4 header – defined in RFC 2475
DiffServ: six most significant bits of ToS byte are called DiffServ Code Point (DSCP) - remaining two bits used for flow control
DiffServ allows nodes to forward packets based on class of traffic as defined by the DiffServ Code Point – defined in RFC 2474
IP Type of Service Byte—As Layer 2 media often changes as packets traverse from source to destination, a more ubiquitous classification would occur at Layer 3. The second byte in an IPv4 packet is the Type of Service (ToS) byte. The first three bits of the ToS byte alone are referred to as the IP Precedence (IPP) bits. These same three bits, in conjunction with the next three bits, are known collectively as the DSCP bits.
The IP Precedence bits, like 802.1p CoS bits, allow for only 8 values of marking (0-7).
IPP values 6 and 7 are generally reserved for network control traffic (such as routing).
IPP value 5 is recommended for voice.
IPP value 4 is shared by video conferencing and streaming video.
IPP value 3 is for voice-control.
IPP values 1 and 2 can be used for data applications.
IPP value 0 is the default marking value.
Many enterprises find IPP marking to be overly restrictive and limiting, favoring instead the 6-Bit/64-value DSCP marking model.

8. Industrial Traffic Prioritization QoS – ODVA DSCP and CoS Priority Values
Traffic Type
CIP Priority
DSCP
Layer 3
CoS
Layer 2
CIP Traffic Usage
PTP event
(IEEE 1588)
n/a 59 7
PTP event messages, used by CIP Sync
PTP General 47 5
PTP management messages, used by CIP Sync
CIP class 0 / 1
Urgent (3) 55 6
CIP Motion
Scheduled (2)
Safety I/O
I/O
High (1) 43
Low (0) 31 3
No recommendations at present
CIP UCMM
CIP class 3
All 27
CIP messaging
ODVA has specified QoS markings for CIP and PTP traffic
Stratix 5700/8000/8300 initial configuration sets up the policing, queuing and scheduling

9. Industrial Traffic Prioritization QoS – ODVA DSCP and CoS Priority Values
CIP Priority
DSCP
Layer 3
CoS
Layer 2
CIP Traffic Usage
Highest 59 7
Beacon, PTP Event
High 55
CIP Motion
Low
43, 47
I/O, Safety I/O, PTP General
Lowest
0-42, 44-46, 48-54, 56-58, 60-63
1, 2, 3, 4, 5, 6
Best effort
Embedded Switch Technology – Linear and Ring Topologies
ODVA has specified QoS markings for CIP and PTP traffic
I/O
I/O
I/O
HMI
HMI
VFD
Drive
Controller
Servo
Drive
VFD
Drive
I/O
Controller
Instrumentation

10. Industrial Traffic Prioritization QoS – Cell/Area Zone Priorities
PTP-Event
Critical Data
Video
Call Signaling
Best Effort
Voice
Bulk Data
Network Control
Scavenger
CIP Explicit
Messaging
CIP Motion
PTP Management, Safety I/O
& I/O
Typical Enterprise QoS
Cell/Area Zone QoS
Priority Queue,
Queue 1
Output
Queue 3
Queue 4
Queue 2
Note: Due to queue characteristics of the Stratix 5700/8000/8300, the queue order of priority is different than general enterprise switch.

11. Industrial Traffic Prioritization QoS – Design Considerations
QoS trust boundary moving from switch access ports to QoS-capable CIP devices
Stratix 5700/8000/8300 Smartport enables Trusted Markings
For existing CIP devices, marking at the switch access port is based on port number
CIP I/O UDP 2222
CIP Explicit TCP 44818
Established through Stratix Express Setup
Prioritize traffic to reduce latency and jitter for CIP I/O traffic
Prioritized traffic delivery for CIP Sync and CIP Motion
Minimize impacts by DDoS attacks
Deploy QoS throughout the IACS network to take better advantage of QoS features
Device w/out QoS marking support
I/O
Drive
HMI
Servo
Drive
CIP Motion or QoS ready device
Controllers
Gigabit
Ethernet
Fast Ethernet
No Trust + Policing + CoS/DSCP Marking + Queuing
Trusted DSCP + CoS Marking + Queuing
Trusted DSCP + CoS Marking + Queuing

12. Industrial Traffic Prioritization QoS – Design and Implementation Considerations
Plant-wide / site-wide networks must prioritize industrial automation and control system (IACS) traffic (CIP) over other traffic types (HTTP, SMTP, etc.) to ensure deterministic data flows with low latency and low jitter
Quality of Service does not increase bandwidth.
QoS gives preferential treatment to EtherNet/IP IACS network traffic at the expense of other network traffic types
QoS is integrated into the Stratix 5700/8000/8300 switch configurations
The Stratix 5700/8000/8300 recognizes or ‘trusts’ QoS capable devices and prioritizes CIP traffic as it exits from the switch
Deploy QoS consistently throughout the EtherNet/IP IACS Network
The more IACS devices that implement QoS, the better that the network infrastructure devices (switches, routers) can take advantage of QoS features

13. EtherNet/IP Advantage Summary
Single industrial network technology for:
Multi-discipline Network Convergence - Discrete, Continuous Process, Batch, Drive, Safety, Motion, Power, Time Synchronization, Supervisory Information, Asset Configuration/Diagnostics, and Energy Management
Established – 375+ vendors, over 7,500,000 nodes
Risk reduction – broad availability of products, applications and vendor support
ODVA: Cisco Systems, Endress+Hauser, Rockwell Automation are principal members
Supported – Defined QoS priority values for EtherNet/IP devices
Standard – IEEE Ethernet and IETF TCP/IP Protocol Suite
Enables convergence of IAT and IT – voice, video and data - common toolsets (assets for design, deployment and troubleshooting) and skills/training (human assets)
Standard IT technology - Standard Layer 2 and Layer 3 Network Services, Segmentation – VLANs, Prioritization – QoS, Time Synchronization – PTP, Multicast Management
Topology and media independence – flexibility and choice
Device-level and switch-level topologies; copper - fiber - wireless
Portability and routability – seamless plant-wide / site-wide information sharing
No data mapping – simplifies design, speeds deployment and reduces risk

14. Additional Material Website: Media Planning and Installation Manual
Media Planning and Installation Manual
Network Infrastructure for EtherNet/IP: Introduction and Considerations
Device Level Ring
The CIP Advantage

15. Additional Material Networks Website: http://www.ab.com/networks/
EtherNet/IP Website:
Media Website:
Embedded Switch Technology Website:
Publications:
ENET-AP005-EN-P Embedded Switch Technology Manual
ENET-UM001G-EN-P EtherNet/IP Modules in Logix5000 Control Systems …. provides connection and packet rate specs for modules
ENET-WP0022 Top 10 Recommendations for plant-wide EtherNet/IP Deployments
ENET-RM002A-EN-P Ethernet Design Considerations Reference Manual
ENET-AT004A-EN-E Segmentation Methods within the Cell/Area Zone
ENET-RM003A-EN-P Embedded Switch Technology Reference Architectures
ENET-WP030A-EN-E Choosing the correct Time Synchronization Protocol
Network and Security Services Website:

16. Additional Material Education Series Webcasts
What every IT professional should know about Plant-Floor Networking
What every Plant-Floor Engineer should know about working with IT
Industrial Ethernet: Introduction to Resiliency
Fundamentals of Secure Remote Access for Plant-Floor Applications and Data
Securing Architectures and Applications for Network Convergence
IT-Ready EtherNet/IP Solutions
Available Online
/products-technologies/network-technology/architectures.page?
People and Process Optimization:
This Series is part of an overall collaboration between Cisco and Rockwell Automation to facilitate convergence between Industrial and Enterprise Networks. The intent of the Education Series is to provide a common reference and understanding on terminology between IT professionals and Control Engineers to facilitate dialogue. Education to facilitate Industrial and IT convergence and help enable successful architecture deployment and efficient operations allowing critical resources to focus on increasing innovation and productivity.
Rockwell Automation and Cisco encourages that IT and Control Engineers watch these video on demands (VoDs) together. Remember, it’s all about facilitating dialogue

17. Additional Material Websites Design Guides Application Guides
Reference Architectures
Design Guides
Converged Plant-wide Ethernet (CPwE)
Application Guides
Fiber Optic Infrastructure Application Guide
Education Series Webcasts
Whitepapers
Top 10 Recommendations for Plant-wide EtherNet/IP Deployments
Securing Manufacturing Computer and Controller Assets
Production Software within Manufacturing Reference Architectures
Achieving Secure Remote Access to plant-floor Applications and Data
Design Considerations for Securing Industrial Automation and Control System Networks - ENET-WP031A-EN-E

18. A new ‘go-to’ resource for educational, technical and thought leadership information about industrial communications
Standard Internet Protocol (IP) for Industrial Applications
Coalition of like-minded companies

19. Plant-wide Benefits of EtherNet/IP Seminar
Networking Design Considerations for Real-Time EtherNet/IP Performance - QoS
Plant-wide Benefits of EtherNet/IP Seminar