Unmodified Ethernet for Industrial Automation? • Benefits of Ethernet for Automation • Ethernet Features – an Overview • Limiting Factors of Ethernet as Fieldbus Replacement SUE: Standard Unmodified Ethernet

Fieldbus Foundation High Speed Ethernet (HSE): What are the benefits of HSE? ….Use of unmodified Ethernet and standard IP makes HSE systems more cost-effective than other Ethernet solutions and proprietary networks…. © EtherCAT Technology Group

Benefits of Ethernet for Automation • Ethernet is in use for Controller/Controller communication since many years, as it saves money to use commodity technologies: Examples: • CAN (originally developed for automotive applications)

• PC-based Controls • Windows + Linux • So Automation benefits from the much larger IT Communication • Thus low cost hard- and software • If also on Fieldbus ( I/O, Sensor and Drives) Level: just one communication technology remaining • Improvement also financed (and driven !) by others

© EtherCAT Technology Group

Ethernet Overview: CSMA/CD, TCP/IP & others • • • • • •

Architecture Physical Layer: Signal, Cables + Wiring Media Access Control Name Resolution Routing IP, TCP + UDP

This diagram was hand drawn by Robert M. Metcalfe and photographed by Dave R. Boggs in 1976 to produce a 35mm slide used to present Ethernet to the National Computer Conference in June of that year. © EtherCAT Technology Group

Ethernet Definition (Wikipedia) Ethernet is a frame-based computer networking technology for local area networks (LANs). It defines wiring and signaling for the physical layer, and frame formats and protocols for the media access control (MAC)/data link layer and a common addressing format Ethernet is standardized as IEEE 802.3. It has become the most widespread LAN technology in use during the 1990s to the present, and has largely replaced all other LAN standards such as token ring, FDDI, and ARCNET.

© EtherCAT Technology Group

Ethernet layer model

IT-Suite Application

DHCP, TFTP, ...

HTTP, FTP, ...

Transport Layer

UDP

TCP

Network Layer

IP

Data Link Layer

Media Access Control (MAC) CSMA/CD

Software

Hardware Physical Layer

UTP Cat. 5, POF, GOF

Ethernet Specification IEEE 802.3

© EtherCAT Technology Group

6

Ethernet Transmission Media (IEEE802) 1BASE5 UTP 10BASE2 Coax 10BASE5 Coax 10BROAD36 Coax 10BASE-T UTP, duplex mode unknown 10BASE-THD UTP, half duplex mode 10BASE-TFD UTP, full duplex mode 10BASE-FP Passive fiber 10BASE-FB Synchronous fiber 10BASE-FL Asynchronous fiber 100BASE-T2 Two-pair Category 3 UTP 100BASE-T4 Four-pair Category 3 UTP 100BASE-TX Two-pair Category 5 UTP 100BASE-FX Two-strand Multimode Fibre 100BASE-VG Four-Pair Category 3 UTP 1000BASE-T Four-pair Category 5 UTP PHY 1000BASE-T X Four-pair Category 6 UTP PHY 1000BASE-LX Multimode Fibre 1000BASE-SX Multimode Fibre or Singlemode Fibre 1000BASE-CX X copper over 150-Ohm balanced cable PMD 1000BASE-BX10 Bidirectional single strand Singlemode Fibre 1000BASE-LX10 Two-strand Singlemode Fibre 1000BASE-PX10 -D Singlemode Fibre, Downstream, 10km 1000BASE-PX10 -U Singlemode Fibre, Upstream, 10km 1000BASE-PX20 -D Singlemode Fibre, Downstream, 20km 1000BASE-PX20 -U Singlemode Fibre, Upstream, 20km 1000BASE-KX 1m over Backplane 10GBASE-X X PCS/PMA over undefined PMD 10GBASE-LX4 X fibre over 4 lane 1310nm optics 10GBASE-CX4 X copper over 8 pair 100-Ohm balanced cable, 15m 10GBASE-R R PCS/PMA over undefined PMD 10GBASE-ER R fibre over 1550nm optics 10GBASE-LR R fibre over 1310nm optics 10GBASE-SR R fibre over 850nm optics © EtherCAT Technology Group

10GBASE-W 10GBASE-EW 10GBASE-LW 10GBASE-SW 10GBASE-KR 10GBASE-KX4 10GBASE-LRM 10GBASE-T 40GBASE-SR4 40GBASE-LR4 40GBASE-CR4 40GBASE-KR4 100GBASE-SR10 100GBASE-LR4 100GBASE-ER4 100GBASE-CR10

W PCS/PMA over undefined PMD W fibre over 1550nm optics W fibre over 1310nm optics W fibre over 850nm optics Backplane Ethernet (802.3ap, 2007) Backplane Ethernet (802.3ap, 2007) multimode Fibre (802.3aq, 2006) UTP (802.3an, 2006) Multimode Fibre, 100m (802.3ba,2010) Singlemode Fibre, 10km (802.3ba,2010) Copper Cable Assembly, 10m (802.3ba,2010) Backplane Ethernet (802.3ba,2010) Multimode Fibre, 100m (802.3ba,2010) Singlemode Fibre, 10km (802.3ba,2010) Singlemode Fibre, 40km (802.3ba,2010) Copper Cable Assembly, 10m (802.3ba,2010)

Large variety of physical layers

Two or Four Pairs? 100BASE-TX

1000BASE-T

two pairs:

four pairs:

• one pair sends

• all four pairs send and receive simultaneously

• one pair receives

• Encoding: PAM-5 – TCM

• Encoding: 4B5B – MLT-3

5-level Pulse Amplitude (PAM-5) with Trellis Coded Modulation (TCM)

Multilevel Transmission Encoding

Tx

Rx

Rx/ Tx

Rx/ Tx

Rx

Tx

Rx/ Tx

Rx/ Tx

Tx

Rx

Rx/ Tx

Rx/ Tx

Tx

Rx/ Tx

Rx/ Tx

Rx

© EtherCAT Technology Group

IEEE 802.3: Media Access Control CSMA/CD “Carrier-Sense Multiple-Access with Collision-Detection”

– The node that wants to send checks if the media is available “Carrier-Sense”

– All nodes are equal and may send autonomously “Multiple-Access” – The sender checks after sending if there was a collision “Collision-Detection”

– maximum Ethernet propagation delay: 25,6µs (@10MBit/s) (determined by cable length & repeater delays)

Start Transmission Carrier Sense undisturbed Transmission

Collision Window © EtherCAT Technology Group

Media Access Control CSMA/CD

Node A

Carrier

Node B

Signal Propagation Delay

Sense

Node A

Multiple

Node B

A starts sending

Access /

Node A

Node B

Collision B starts sending

Detection Node A

© EtherCAT Technology Group

Collision

Node B

Ethernet Collision Domain Hub

B

Hub

• Hubs • half duplex

• Hub Cascading & Length limited

A © EtherCAT Technology Group

Switched Ethernet Topology Switch

B

• Switches

Switch

• full duplex

full duplex communication

Switch sends single cast communication only to the destination port

© EtherCAT Technology Group

Queues avoid collisions

A

“Store and Forward” vs. “Cut-Through” Most Switches use the “Store and Forward” principle: • Receive entire frame first, check FCS, then forward to destination port. • Advantage: only “healthy” frames are forwarded. • Disadvantage: large and variable forwarding delay (ca. 10…125 µs, depending on frame length –the buffer delay comes on top)

Preamble SFD DA

SA LEN DATA

Pad

FCS

Only very few Switches make use of the “Cut-Through” principle: • Frames are forwarded shortly after receiving the destination address. • Advantage: shorter delay (ca. 5…7 µs) • Disadvantage: corrupted frames are forwarded as well Preamble SFD DA

SA LEN DATA

© EtherCAT Technology Group

Pad

FCS

Ethernet Packet

7

1

6

Preamble SFD DA

6

2

46-1500

0-46

SA LEN DATA

Length

Pad

Data „Payload“

Sender Address Destination Address

4

Byte

FCS

Frame Check Sequence (CRC) Padding Field

Start Frame Delimiter „10101011“ Preamble “1010101010.....” used for Bit Synchronisation

• The Length Byte has two meanings: if it is >0x5DC then it describes the type of the “payload” (Ethertype, e.g. IP 0x0800 or ARP 0x0806 or EtherCAT 0x88A4) • If the data length is 239: Class E (reserved)

Since 1993: Inflexible Classes replaced by more flexible Classless Inter-Domain Routing © EtherCAT Technology Group

Problem: Shortage of IP Addresses IPv4: 32bits = 232= 4,294,967,296 nodes maximum, out of which only 3.706.650.624 can be used (Rest: Class D+E + Special Usage)

Estimated Internet Users worldwide: 2,267,233,742 (Dec 31, 2011)

Source: Internet World Stats – www.internetworldstats.com/stats.htm

© EtherCAT Technology Group

IPv4 Address Exhaustion now in final stage • On February 3, 2011, the Internet Assigned Numbers Authority (IANA) allocated the last 5 blocks of IPv4 addresses to the 5 Regional Internet Registries (RIR) • On April 19, 2011, APNIC (Asia Pacific), ran out of addresses. • Raúl Echeberría, Feb 3, 2011 Chairman of the Number Resource Organization (NRO), the official representative of the five RIRs: “This is an historic day in the history of the Internet, and one we have been anticipating for quite some time. The future of the Internet is in IPv6. All Internet stakeholders must now take definitive action to deploy IPv6.”

© EtherCAT Technology Group

The solution: IPv6 with 3.4 x 1038 Addresses! IPv6: 128bits = 2128= 340,282,366,920,938,463,463,374,607,431,768,211,456 nodes maximum – or approximately 4.8 x 1028 for every person alive

– or approximately 4.5 x 1015 for each observable star in the known universe

40 Bytes

IPv6 Header Version Traffic Class 16bit Payload Length Source IP address, Bits 0..31 Source IP address, Bits 32..63

Flow Label Next Header

Hop Limit

Source IP address, Bits 64..95 Source IP address, Bits 96..127 Destination IP address, Bits 0..31 Destination IP address, Bits 32..63 Destination IP address, Bits 64..95 Destination IP address, Bits 96..127

However: slow adoption rate of this new internet protocol generation (March 28, 2012: only 0,48%* of the Google users has IPv6) © EtherCAT Technology Group

* Source: www.google.com/intl/en/ipv6/statistics/

The intermediate solution: Private Addresses • Private IP Addresses, non routable: 10.0.0.0 to 10.255.255.255 172.16.0.0 to 172.31.255.255 192.168.0.0 to 192.186.255.255 Example: local Network Class B 172.16.20.3

172.16.17.103

IP-Device

IP-Device

172.16.20.2

172.16.17.102

IP-Device

IP-Device

172.16.20.1

172.16.17.101

IP-Device

IP-Device

172.16.1.1

180.1.1.1

Router

• but: IP Masquerading (NAT), Proxy,… (communication from local network to internet only)

© EtherCAT Technology Group

IP Routing: functionality Classless Inter-Domain Routing 1. within Subnet: Address resolution with ARP 2. if IP Address outside Subnet: send Data with Destination IP Adresse and Gateway-MAC-ID 3. Private Networks (non routable IP Addresses) cannot be reached from outside (IP-Masquerading)

168.12.41.52 Gateway 10.13.102.1

10.13.2.2

194.175.173.88 © EtherCAT Technology Group

IP Routing: Example

A

IP Address:

10.13.2.2

Subnet Mask:

255.255.0.0

Gateway

10.13.102.1

Ethernet MAC ID

00-01-01-02-03-04

-Wants to FTP with 194.175.173.88 -FTP control: well known port 21 (TCP)

FTP

168.12.41.52 Gateway 10.13.102.1

from port 21

TCP to port 21

A 194.175.173.88

10.13.2.2 © EtherCAT Technology Group

IP Routing: Example

A

IP Address:

10.13.2.2

Subnet Mask:

255.255.0.0

Gateway

10.13.102.1

Ethernet MAC ID

00-01-01-02-03-04

-TCP passes TCP Datagram to IP

168.12.41.52 Gateway 10.13.102.1

from 10.13.2.2

IP to 194.175.173.88

A 194.175.173.88

10.13.2.2 © EtherCAT Technology Group

IP Routing: Example

A

IP Address:

10.13.2.2

Subnet Mask:

255.255.0.0

Gateway

10.13.102.1

Ethernet MAC ID

00-01-01-02-03-04

-IP compares IP Addresses according to subnet mask Subnet mask 255.255.0.0

11111111 11111111 00000000 00000000

own IP Addr. 10.13.2.2

00001010 00001101 00000010 00000010

Destination 194.175.173.88 11000010 10101111 10101101 01011000

168.12.41.52 Gateway

-result: Net ID parts differ, therefore different net, data has to be forwarded to gateway

10.13.102.1

A 194.175.173.88

10.13.2.2 © EtherCAT Technology Group

IP Routing: Example

A

IP Address:

10.13.2.2

Subnet Mask:

255.255.0.0

Gateway

10.13.102.1

Ethernet MAC ID

00-01-01-02-03-04

-What is the MAC ID of the Gateway? -Node A sends ARP request

-broadcast with “what is the MAC ID of IP Address 10.13.102.1? -Gateway answers with ARP response:

168.12.41.52 Gateway

-I am 10.13.102.1 and my MAC ID is ….

-Node A enters this MAC ID in ARP cache

10.13.102.1

A 194.175.173.88

10.13.2.2 © EtherCAT Technology Group

IP Routing: Example

A

IP Address:

10.13.2.2

Subnet Mask:

255.255.0.0

Gateway

10.13.102.1

Ethernet MAC ID

00-01-01-02-03-04

-ARP cache of Node A (cmd: arp –a)

168.12.41.52

Internet Address

Physical address

Type

10.13.102.1

00-a0-f9-02-d0-70

dynamic

10.13.2.3

00-05-01-0a-03-02

dynamic

Gateway 10.13.102.1

A 194.175.173.88

10.13.2.2 © EtherCAT Technology Group

IP Routing: Example

A

IP Address:

10.13.2.2

Subnet Mask:

255.255.0.0

Gateway

10.13.102.1

Ethernet MAC ID

00-01-01-02-03-04

-Ethernet driver packs the IP datagram in an Ethernet packet and sends it to the gateway

168.12.41.52 Gateway 10.13.102.1

from Ethernet 01-01-01-02-03-04 to 00-a0-f9-02-d0-70

A 194.175.173.88

10.13.2.2 © EtherCAT Technology Group

IP Routing: Example

B

internal IP Address: 10.13.102.1 Subnet Mask: 255.255.0.0 Ethernet MAC ID 00-a0-f9-02-d0-70 external IP Address 168.12.41.52 Subnet Mask: 255.255.0.0 Gateway 168.12.78.234 Ethernet MAC ID 00-03-47-4A-1A-FF

-Gateway unpacks IP datagram from Ethernet frame

B 168.12.41.52 Gateway

from 10.13.2.1

IP to 194.175.173.88

10.13.102.1

A 10.13.2.2

194.175.173.88 © EtherCAT Technology Group

IP Routing: Example

B

internal IP Address: 10.13.102.1 Subnet Mask: 255.255.0.0 Ethernet MAC ID 00-a0-f9-02-d0-70 external IP Address 168.12.41.52 Subnet Mask: 255.255.0.0 Gateway 168.12.78.234 Ethernet MAC ID 00-03-47-4A-1A-FF

- Replaces local IP Address by its own external IP Address (NAT, IP Masquerading)

B 168.12.41.52 Gateway

from IP 10.13.2.1 168.12.41.52 to 194.175.173.88

10.13.102.1

A 10.13.2.2

194.175.173.88 © EtherCAT Technology Group

© EtherCAT Technology Group

Ethernet – Transmission Control Protocol (TCP)

20 Bytes

• Connection oriented data transport, carried in IP data • Point to point between exactly two host ports • Reliable: Transfers are acknowledged, Order of sequential packets maintained • Data transferred as a stream of bytes • Good for protocols needing to move streams of data • - HTTP, FTP, SMTP 16bit source port number 16bit destination port number • Only works with unicast 32bit sequence number IP addresses 32bit acknowledgement number • No broadcast HDR LEN (reserved) flags 16bit window size 16bit TCP checksum 16bit urgent pointer or multicast TCP data (theoretically up to 65495 Bytes, typically restricted by the implementation)

IP

SA

IP-HDR (Protokoll=06)

DA 0800

TCP Header and Data

IP Header and Data

© EtherCAT Technology Group

CRC

Ethernet: TCP Handshaking Host 1

• Establish: Three way handshake between two hosts Host 1 sends SYN (synchronize) to host 2 Host 2 sends ACK to host 1 along with its own SYN Host 1 sends ACK to host 2 • Terminate: Four way handshake Host 1 sends FIN (final) to host 2 Host 2 send ACK to host 1 Host 2 (in a separate message) sends FIN to host 1 Host 1 sends ACK to host 2

Host 2 SYN ACK, SYN ACK

Host 1

Host 2 FIN

ACK FIN ACK

it takes some time to establish/terminate a connection!

© EtherCAT Technology Group

Ethernet User Datagram Protocol (UDP)

8 Bytes

• Simple datagram-oriented data transport, carried in IP data • Non-guaranteed delivery of data Packets may be delivered out of order or may not be delivered at all! • Less overhead than TCP • Needed for broadcast and multicast applications • Suitable for request / response type protocols (polling) SNMP TFTP 16bit source port number 16bit destination port number DHCP / BOOTP 16bit UDP length 16bit UDP checksum UDP data (theoretically up to 65507 Bytes, typically restricted by the implementation)

IP

SA

IP-HDR (Protokoll=17)

DA 0800

UDP Header and Data

IP Header and Data

© EtherCAT Technology Group

CRC

Network Layer Protocols found in RFC 826 (ARP): • • • • • • •

ARP, Address Resolution Protocol. DRARP, Dynamic RARP. InARP, Inverse Address Resolution Protocol. IP, Internet Protocol. IPv6, Internet Protocol version 6. MPLS, Multi-Protocol Label Switching. RARP, Reverse Address Resolution Protocol.

© EtherCAT Technology Group

„The world is a jungle in general, and the networking game contributes many animals. At nearly every layer of a network architecture there are several potential protocols that could be used.“

Transport Layer Protocols • • • • • • • • • • • • • • • • • • • • • • • •

AH, IP Authentication Header. AX.25. CBT, Core Based Trees. DVMRP, Distance Vector Multicast Routing Protocol. EGP, Exterior Gateway Protocol. ESP, Encapsulating Security Payload. GGP, Gateway to Gateway Protocol. GRE, Generic Routing Encapsulation. HMP, Host Monitoring Protocol. ICMP, Internet Control Message Protocol. ICMPv6, Internet Control Message Protocol for IPv6. IDPR, Inter-Domain Policy Routing Protocol. IFMP, Ipsilon Flow Management Protocol. IGAP, IGMP for user Authentication Protocol. IGMP, Internet Group Management Protocol. IGRP, Interior Gateway Routing Protocol. IP in IP Encapsulation. IPPCP, IP Payload Compression Protocol. IRTP, Internet Reliable Transaction Protocol. ISO-IP. L2TP, Level 2 Tunneling Protocol. Minimal Encapsulation Protocol. MLD, Multicast Listener Discovery. Mobility Header © EtherCAT Technology Group

• • • • • • • • • • • • • • • • • • • • • • •

MOSPF, Multicast Open Shortest Path First. MTP, Multicast Transport Protocol. NARP, NBMA Address Resolution Protocol. NETBLT, Network Block Transfer. NVP, Network Voice Protocol. OSPF, Open Shortest Path First Routing Protocol. PGM, Pragmatic General Multicast. PIM, Protocol Independent Multicast. PTP, Performance Transparency Protocol. RDP, Reliable Data Protocol. RSVP, Resource ReSerVation Protocol. SCTP, Stream Control Transmission Protocol. SEND, SEcure Neighbor Discovery. SDRP, Source Demand Routing Protocol. SKIP, Simple Key management for Internet Protocol. ST, Internet Stream Protocol. TCP, Transmission Control Protocol. TMux, Transport Multiplexing Protocol. TP/IX. UDP, User Datagram Protocol. UDP-Lite, Lightweight User Datagram Protocol. VMTP, Versatile Message Transaction Protocol. VRRP, Virtual Router Redundancy Protocol.

Application Layer Protocols (I) • • • • • • • • • • • • • • • • • • • • •

ACAP, Application Configuration Access Protocol. AgentX. AODV, Ad hoc On-Demand Distance Vector. APEX, Application Exchange Core. ATMP, Ascend Tunnel Management Protocol. AURP, AppleTalk Update-based Routing Protocol. Authentication Server Protocol. BFTP, Background File Transfer Program. BGP, Border Gateway Protocol. BOOTP, Bootstrap Protocol. CFDP, Coherent File Distribution Protocol. Chargen, Character Generator Protocol. CLDAP, Connection-less Lightweight X.500 Directory Access Protocol. COPS, Common Open Policy Service. CRANE, Common Reliable Accounting for Network Element. Daytime, Daytime Protocol. DCAP, Data Link Switching Client Access Protocol. DHCP, Dynamic Host Configuration Protocol. DHCPv6, Dynamic Host Configuration Protocol for IPv6. DIAMETER. DICT, Dictionary Server Protocol.

© EtherCAT Technology Group

• • • • • • • • • • • • • • • • • • • • • • •

Discard, Discard Protocol. DIXIE. DMSP, Distributed Mail Service Protocol. DNS, Domain Name System. DRAP, Data Link Switching Remote Access Protocol. DTCP, Dynamic Tunnel Configuration Protocol. Echo. EMSD, Efficient Mail Submission and Delivery. EPP, Extensible Provisioning Protocol. ESRO, Efficient Short Remote Operations. ETFTP, Enhanced Trivial File Transfer Protocol. Finger. FTP, File Transfer Protocol. GDOI, Group Domain of Interpretation. Gopher. HOSTNAME. HSRP, Hot Standby Router Protocol. HTTP, HyperText Transfer Protocol. ICAP, Internet Content Adaptation Protocol. ICP, Internet Cache Protocol. iFCP, Internet Fibre Channel Protocol. IKE, Internet Key Exchange. IMAP, Interactive Mail Access Protocol.

Application Layer Protocols (II) • • • • • • • • • • • • • • • • •

• • • •

IPFIX, IP Flow Information Export. IPP, Internet Printing Protocol. IRC, Internet Relay Chat. ISAKMP, Internet Security Association and Key Management Protocol. iSCSI. IUA, ISDN Q.921-User Adaptation. Kerberos. Kermit. L2F, Layer 2 Forwarding. L2TP, Level 2 Tunneling Protocol. LDAP, Lightweight Directory Access Protocol. LDP, Label Distribution Protocol. LDP, Loader Debugger Protocol. LFAP, Light-weight Flow Admission Protocol. LMTP, Local Mail Transfer Protocol. LPR. MADCAP, Multicast Address Dynamic Client Allocation Protocol. MASC, Multicast Address-Set Claim. MATIP, Mapping of Airline Traffic over Internet Protocol. Mbus, Message Bus. MGCP, Multimedia Gateway Control Protocol. © EtherCAT Technology Group

• • • • • • • • • • • • • • • • • • • • •

Mobile IP. MPP, Message Posting Protocol. MSDP, Multicast Source Discovery Protocol. MTP, Mail Transfer Protocol. MTQP, Message Tracking Query Protocol. MUPDATE, Malbox Update. NAS, Netnews Administration System. NFILE. NFS, Network File System. NNTP, Network News Transfer Protocol. NTP, Network Time Protocol. ODETTE-FTP, ODETTE File Transfer Protocol. OLSR, Optimized Link State Routing. Ph. Photuris. POP, Post Office Protocol. Portmapper. PPTP, Point to Point Tunneling Protocol. PWDGEN, Password Generator Protocol. Quote, Quote of the Day Protocol. RADIUS, Remote Authentication Dial-In User Service. • RAP, Internet Route Access Protocol. • RIP, Routing Information Protocol.

Application Layer Protocols (III) • • • • • • • • • • • • • • • • • • • • • • • •

RIPng. Rlogin. RLP, Resource Location Protocol. RMCP, Remote Mail Checking Protocol. RSIP, Realm Specific IP. RTCP, RTP Control Protocol. RTP, Real-Time Transport Protocol. RTSP, Real Time Streaming Protocol. RWhois, Referral Whois Protocol. SACRED, Securely Available Credentials. Send, Message Send Protocol. SFTP, Simple File Transfer Protocol. SGMP, Simple Gateway Monitoring Protocol. SIFT/UFT, Sender-Initiated/Unsolicited File Transfer. SIP, Session Initiation Protocol. SLP, Service Location Protocol. SMTP, Simple Mail Transfer Protocol. SMUX. SNMP, Simple Network Management Protocol. SNPP, Simple Network Paging Protocol. SNTP, Simple Network Time Protocol. SOCKS. SRTCP, Secure RTCP. SRTP, Secure Real-time Transport Protocol. © EtherCAT Technology Group

• • • • • • • • • • • • • • • • • • • • •

SSP, Switch-to-Switch Protocol. STATSRV, Statistics Server. STUN, Simple Traversal of UDP Through NAT. SUA, Signalling Connection Control Part User Adaptation Layer. Syslog. SYSTAT. TACACS. TBRPF, Topology Broadcast based on Reverse-Path Forwarding. Telnet. TFTP, Trivial File Transfer Protocol. Time, Time Protocol. TRIP, Telephone Routing over IP. TSP, Time Stamp Protocol. TUNNEL. UMSP, Unified Memory Space Protocol. UUCP. VEMMI, VErsatile MultiMedia Interface. WebDAV, Web Distributed Authoring and Versioning. Whois. Whois++. Z39.50.

Ethernet Introduction: Summary •

Ethernet is the technology described in the IEEE 802.3 standards

•

The term „Ethernet“ is mistakingly used for a suite of network technologies: Ethernet, IP, TCP, UDP, FTP, HTTP and more, which are also referred to as the „Internet Technologies“

•

Stacking of protocol layers – and thus tunneling of protocols – is a key feature of the Internet Technologies.

•

Ethernet is used on a large variety of physical layers.

•

Switching topologies have replaced collision domains – CSMA/CD is legacy technology, hubs are outdated.

•

TCP/IP is a powerful protocol implemented in rather complex software stacks.

© EtherCAT Technology Group

Unmodified Ethernet for Industrial Automation? •

What looks like a good idea in the first place seems to be pretty complex

•

Achieving Real Time Performance with unmodified Ethernet seems to require a lot of IT know how and looks challenging

•

Even those that claimed to make use of unmodified Ethernet throughout now use FPGAs instead of standard MACs

•

Further details can be found in the Industrial Ethernet comparison available for download here: www.ethercat.org/pdf/english/Industrial_Ethernet_Technologies.pdf

© EtherCAT Technology Group