Using VLAN’s in an ITS / Traffic network What is Ethenet

• Network devices communicate using the Protocol (IEEE 802.3). • It uses packets to transfer data to and from devices. • It is a standard communications protocol embedded in software and hardware devices, intended for building a (LAN). Why use Ethernet

•It is flexible

•Saves money and resources in terms of infrastructure.

•Scalability.

•The entire industry is moving towards it.

•STANDARDS BASED ITS Ethernet attached Devices

• Key Components – Traffic Controllers – Traffic Detectors – Video Surveillance – Conflict Monitors – Temperature Sensors Typical Cabinet Network

Fiber 90km 100Mbps 100Mbps 90km

Switch (Top View) Serial Device Server

Switch

OR Curb-side Video 2070 170 Traffic Control Encoder Controller Controller Cabinet

LEGEND

CAT 5 10/100BaseT Fiber Optical (100BaseFX) Serial Cable (RS232/485/422) ITS Application (Add-Drop Architecture)

NMS Traffic Control Center

RSG2100 Field Hardened Mid-Level Serial Device Server Ethernet Switch with Integrated Ethernet Switch

90km 90km 100Mbps Fiber Optical Ethernet Ring RS400 RS400 90km 90km

RS400 Networking Overview The Open Systems Interconnect (OSI) Reference Model

• Networks are complicated!!!

• Models allow us to simplify complicated problems by splitting them into smaller pieces.

• OSI Reference Model provides a framework for both designing networking system and for explaining how they work.

• The existence of the model makes it easier for networks to be analyzed, designed, built and rearranged, by allowing them to be considered as modular pieces that interact in predictable ways. The OSI Model

DNP3/TCP ProfiNet IEC61850(UCA2) Fieldbus HSE EtherNet/IP Modbus/TCP

Application HTTP SMTP FTP

Presentation

Session

Transport TCP/UDP TCP/IP Network IP Data Link IEEE 802.1 Ethernet Physical IEEE 802.3 Network “Layers”

• OSI Seven Layer Reference Model

7 Application 6 Presentation 5 Session Control 4 Transport 3 Network / Protocol / Routing 2 Data Link / MAC 1 Physical

Please Do Not Throw Sausage Pizza Away • The layer that we generally are concerned with:

• Physical (Layer 1) • Data Link (Layer 2) • Network (Layer 3) Physical Layer 1

• Definition of Hardware Specifications

• Encoding and Signaling

• Data Transmission and Reception

• Topology and Physical Network Design Data 2

• Switches work at Layer 2

• is the protocol layer which transfers data between adjacent network nodes or between nodes on the same local area .

• The Data Link Layer also serves the function of media access control (MAC).

• Packets are switched across the network based on there MAC address MAC Addresses

• A MAC address is the hardware address of the Ethernet Device • Each Ethernet device has a unique MAC address • The Address is assigned by the manufacturer at the factory and usually can not be changed • Six bytes in length, 12 hex characters • Usually written as MM-MM-MM-SS-SS-SS or MM:MM:MM:SS:SS:SS • First half of the address is the ID of the manufacturer and is assigned by ICAN. • The second half contains the serial number assigned to the adapter by the manufacturer. Layer 2 and Layer 3

• Layer 2 and Layer 3 are the layers that we are concerned with.

• Layer 2 Data Link Layer Switches operate at this layer Uses MAC addresses to switch traffic Only used in LANS

• Layer 3 Network Layer Also called the IP Layer Uses IP addresses to traffic from one network or subnet to another. Network Layer or Layer 3

•Network Layer is responsible for end-to-end (source to destination) packet delivery including any routing through intermediate hosts, whereas the link layer is responsible for -to-node (hop- to-hop) frame delivery on the same link

• This layer uses the IP address to route the traffic from one network to another

•Routers use the IP address to route traffic. Network Devices Network Devices

• Network devices fall into the first three layers of the OSI Model

Hubs: Physical layer, or the Layer 1. the packets are broadcast all ports at once.

Switches: Data link layer, or Layer 2. The packets are switched based on there destination MAC address

Routers: Network layer or Layer 3. The packets routed across different networks using the IP address. Hubs • Developed as a cost-effective way of attaching multiple devices to a common central point in a star topology

• Works at Layer 1 only – does not understand

• Repeats incoming signal all other ports with restored timing and signal strength with negligible delay

• Requires CSMA/CD i.e. collisions & non-deterministic

• Half-duplex only

• Has a collision domain restricting network diameter to 200 meters • Switches Switches

Switches operate at Layer 2

Can be managed Via a console port, telnet or Web

Supports some Layer Two/Three Protocols such as.

STP/RSTP IGMP SNMP NTP VLAN’s Switching and MAC Address

• Switches learn where stations are by capturing the incoming source MAC address.

• Builds a table (MAC Address Table) of source and destination MAC addresses that correspond to the ports that they are received on.

• Forwards unicast frames only through appropriate port.

• ‘Floods’ frames for unknown addresses MAC Address Table Routers Routers

Routers are devices that route packets based on their IP addresses the operate at Layer 3 or the Network layer. Addresses that are not on the local subnet are sent to the gateway or to be sent out the appropriate interface.

An example of a router is the DSL modem/ Router is the home. IP addresses IP Addresses

• Globally unique address 32 bits in length

• Expressed as 4 octets 192.168.0.1, known as dotted decimal notation

• Valid numbers range for 0 to 255 (8 bits)

• Composed of network and host addresses

• Requires use of a network mask

• Current version is IPV4 next version is IPV6 Types of Traffic. •Broadcast • •Unicast Unicast Traffic

• Simply traffic that is bound for a specific IP address. Broadcast Traffic

• Broadcast Traffic

• Used for network wide communications • All devices on the that segment of the network receive the packets • Layer 2 only • ARPS are typical examples • Broadcasts storms can bring a network down Multicast Traffic

• Multicast traffic is sent to every port in the network.

• Controlled using IGMP snooping

• Typically used in Video applications.

• Users subscribe or request the stream from the Multicast Router.

• Both Layer 2 Multicast and Layer 3 Multicast Virtual LANs (VLANs) VLANS

• Virtual Local Area Network • A logical grouping of ports (on a single device or across multiple switches) • A Layer 3 device is required to communicate between VLANs VLAN Advanced - Basic Facts

• Used construct separate “virtual” networks • Each VLAN is defined by the VLAN ID or VID • IEEE 802.1q defines how to carry multiple VLANs over the same physical link (between switches) • Broadcasts are contained to a single VLAN Trunk Ports and Edge Ports Trunk Ports Trunk Ports are ports that interconnect switches across the network. They carry all VLAN traffic.

Edge Ports Edge ports are usually connected to a Device or a PC, and it only carries on a Single Pre-Configured VLAN the Native VLAN. Example without VLANS

Traffic Video Server Sensor Application

Video Video Sensor Sensor Example with VLANS

Router

Video Server Traffic Sensor Application

VLAN 1

VLAN 2

Video Video Sensor Sensor VLANS in the ITS Network

• Separate Traffic in to different types – Video – Controlers – Sensor – Management • Provide security between different types of traffic. – i.e television stations need only the video and not access to the controllers or sensors. • Provide stability for network traffic. – If there is an issue on one network it will not effect the traffic on the other network.