User's Manual

17
Document Number: 0100SM1401 Issue: 12-16
Operating Modes
Introduction
This section assumes the reader has an operational understanding of industrial Ethernet.
A typical Ethernet network consists of a number of IP devices, all which share the requirement of data communication. In
order for a pair of devices within an Ethernet based network to communicate with one another, they need to be able to
address data to a specific destination (in this case, each other).
MAC Address - MAC addresses identify Ethernet devices on a network when operating at Layer-2. All Ethernet ports in
devices have their own unique media access control (MAC) address. There are special MAC addresses used for broadcast
and Multicast messages.
IP Address - An IP address is a numerical label assigned to each device (e.g., Radio, RTU, SCADA Host) participating in a
computer network that uses the Internet Protocol for communication.
An IP address serves two principal functions:
• Host or network interface identification and
• Location addressing.
Subnet - A subnet is a subdivision of an IP network. It allows a network designer to segment a large IP network into
smaller, manageable sub networks. This can assist in the allocation of IP addresses and the management of network
bandwidth.
Subnet Mask - Together with the IP address, the subnet mask is used to determine which subnet a device belongs to.
Gateway - A gateway forwards IP messages between devices on different subnets in an IP network. A gateway uses
configurable routing rules to determine where to forward an IP message.
Route - A route is a rule that indicates where an IP message needs to be sent in order to get to a specific device on an IP network.
Transparent Bridge Mode
The Q data radios can be configured to operate in a transparent bridge mode. This mode transports all data as layer 2 Ethernet
traffic over the radio network. Each radio will behave like a layer 2 Ethernet switch, transparently forwarding traffic, based on
rules, dynamically determined from device MAC addresses. Traffic can also be repeated in any one single radio in the network
using a peer to peer repeat function (an enable/disable function, typically enabled in repeaters). Each radio requires an IP
address and mask to be configured in order for a user to access radio management features (web server/Telnet/diagnostics/
etc..). The example below shows a typical PTMP/R topology, with all radios operating in bridge mode.
From an IP network perspective, each radio within the topology above, effectively looks like an Ethernet switch. See the
example below.
Part C – System Topologies & Operating Modes