Ethernet Basics Rev. 02 Contents 1 Introduction 1 1.1 The OSI model . .1 1.2LAN............................................3 2 Ethernet 5 2.1 Introduction . .5 2.2 The physical implementations . .6 2.2.1 Implementations based on coax . .7 2.2.2 Implementations based on twisted pair . .7 2.2.3 Implementations based on fibre . 11 2.2.4 Wireless LAN . 11 2.2.5 Bluetooth . 14 2.3 The data link layer . 16 2.3.1 Introduction . 16 2.3.2 MAC address . 16 2.3.3 The Ethernet dataframe . 17 2.3.4 CSMA/CD . 18 2.3.5 CSMA/CA . 20 2.4 Structure elements for Ethernet . 21 2.4.1 The hub . 21 2.4.2 The switch . 22 2.5 IEEE802.1Q tagged frame . 24 2.6 Power over Ethernet . 24 2.6.1 PSE . 25 2.6.2 PD . 25 2.6.3 Alternative A . 26 2.6.4 Alternative B . 26 2.7 VLAN . 28 2.7.1 Advantages of VLANs . 28 2.7.2 Trunking . 28 2.7.3 VLAN types . 29 2.8 Network redundancy . 30 2.8.1 Introduction . 30 2.8.2 The Spanning Tree Protocol . 30 2.8.3 The Rapid Spanning Tree Protocol . 30 2.8.4 Bridge Protocol Data Units (BPDUs) . 31 2.8.5 Multiple Spanning Tree Protocol (MSTP) . 32 2.8.6 Media Redundancy Protocol . 32 Contents ii 2.8.7 Parallel Redundancy Protocol . 32 2.9 Important additions . 32 2.9.1 LLDP . 32 2.9.2 IEEE 802.1x . 33 2.9.3 Link Aggregation with LACP to IEEE 802.3ad . 34 2.10Industrial Ethernet . 35 3 TCP/IP 37 3.1 Introduction . 37 3.2 The Internet Protocol (IP) . 38 3.2.1 Introduction . 38 3.2.2 The IP address . 39 3.2.3 Routers and subnet masking . 42 3.2.4 Subnetting . 43 3.2.5 Classless Inter-Domain Routing . 44 3.2.6 Examples . 45 3.2.7 The IP packet . 46 3.2.8 IPv6 . 48 3.3 Transmission Control Protocol (TCP) . 49 3.3.1 Introduction . 49 3.3.2 End-to-end transport service . 49 3.3.3 How reliability is achieved . 50 3.3.4 The TCP segment . 51 3.4 UDP . 53 3.5 TCP and UDP ports within the automation. 55 3.6 Communication over TCP(UDP)/IP . 56 3.6.1 Client Server model . 56 3.6.2 Endpoint and Internetsocket . 57 3.6.3 Dynamic Servers . 58 3.6.4 Unambiguous communication . 58 3.6.5 Status of a socket . 60 3.6.6 Connection-oriented communication and connectionless communication . 60 4 Extension protocols and network applications 61 4.1 ARP . 61 4.1.1 Introduction . 61 4.1.2 Address Resolution Protocol (ARP) . 61 4.2 BootP and DHCP . 62 4.2.1 Introduction . 62 4.2.2 BootP . 62 4.2.3 DHCP . 63 4.2.4 DHCP Relay Agent - DHCP option 82 . 63 4.3 ICMP . 64 4.3.1 Introduction . 64 4.3.2 Internet Control Message Protocol . 64 4.3.3 ICMP message . 65 4.3.4 Check accessibility of a host . 65 4.3.5 Trace a route . 66 4.4 IGMP . 67 Contents iii 4.4.1 Introduction . 67 4.4.2 IGMP messages . 67 4.4.3 IGMP snooping . 68 4.4.4 Multicast addresses . 68 4.5 GMRP . 69 4.5.1 IEEE 802.1p . 69 4.5.2 GMRP processing . 69 4.6 DNS . 70 4.6.1 Introduction . 70 4.6.2 The structure of a host name . 70 4.6.3 Functioning of the DNS protocol . 71 4.7 SNMP . 72 4.7.1 Introduction . 72 4.7.2 SNMP structure . 73 4.7.3 The MIB and SMI . 74 4.7.4 SNMP protocol . 76 4.8 HTTP and HTTPS . 77 4.8.1 TLS/SSL . ..