DHCP Manager

DHCP MANAGER

Overview

The DNP3 Router allows the user to integrate DNP3 devices over a secure link into a Rockwell Logix platform (e.g. ControlLogix or CompactLogix) with minimal effort.

The DHCP Manager provides location co-ordinated IP Address assignment to DLR capable (embedded switch) devices connected in a linear topology. In applications where different sub-systems can be connected in any order, the module ensures that their IP addresses are assigned in the order in which they are located. Examples of this application can be found in the packaging industry.

DHCP

The Dynamic Host Configuration Protocol (DHCP) is a standard network protocol that is capable of dynamically assigning IP addresses and other network parameters to any device on the network that requests it. This significantly reduces the effort required by network administrators. An IP address pool is provisioned to the DHCP server, and it will assign these IP addresses incrementally typically using a first-come-first-served methodology. Additional network parameters including subnet masks, default gateways etc. can also be assigned by the DHCP server.

Location Co-ordinated IP address assignment

In traditional DHCP assignment, the IP Address assignment for devices typically follows the order in which they are connected or powered up. With the Aparian DHCP Manager, the IP Addresses are assigned to match the physical location or position on the linear network.

The DHCP Manager is able to serve IP addresses to devices that are not directly part of the embedded switch linear topology. Such devices could either be connected at the end of the network, or be connected using 3 port devices such as ETAP modules.

There are two strategies or modes that control the assignment of these devices:

  • Normal mode
  • ETAP-Child mode.

Depending on the mode, different classes of devices are assigned IP addresses from one of the three different IP ranges configured in the module.

The different classes of modules are defined as follows:

Device Class Description
Ordered Devices that are embedded switch, Device-Level-Ring capable, devices connected in the linear network. IP addresses are assigned from the Ordered IP range.
Child Devices that are connected to the third port of a three-port device (e.g. ETAP) located on the linear network. This class of device is only valid in the ETAP-Child mode. Only one child can exist for each three-port device. Any additional devices found connected to that port will be defined as visitors and not children. IP addresses are assigned from the Child IP range.
Visitor All other devices that are connected to the network will be visitors. These included multiple modules connected off a three-port device, or non-DLR devices connected to the end of the linear network. IP addresses are assigned from the Visitor IP range.

 

Mode Description
Normal All devices in the linear topology (including three port devices) are assigned location co-ordinated IP addresses from the Ordered IP range. All other devices are assigned IP addresses from the Visitor IP range.
ETAP-Child All devices in the linear topology (including three port devices) are assigned location co-ordinated IP addresses from the Ordered IP range. Each child (device connected to the third port of a three-port device) will be assigned an IP address from the Child IP range. The offset within the Child IP range will be equal to that of the offset of the parent three-port device in the ordered range. For example, if an ETAP is the 5th device in the linear network, it will be assigned the 5th IP address in the Ordered IP range. Its child will be assigned the 5th IP address in the Child IP range, irrespective of how many preceding children there are. All other devices are assigned IP addresses from the Visitor IP range.

The DHCP Manager is configured using the Aparian Slate application. Slate offers various configuration methods, including a controller tag browser.

The module can operate in both a Logix “owned” and standalone mode. With a Logix connection the input and output assemblies will provide additional diagnostics information which will be available in the Logix controller environment.

A built-in webserver provides detailed diagnostics of system configuration and operation, without the need for any additional software.