Installation guide

Network Infrastructure for EtherNet/IP™
Deploying the Network
5-61
Linux and UNIX computers can send pings from the command line as well, but if a count is not specified,
the computer will continue to send pings until a terminate command is given by hitting [Ctrl-c]. To
specify a number of pings under UNIX or Linux, type [ping –c x 192.168.25.25] where x is the number of
pings to be sent to the address that follows.
Ping can be used to validate connections and IP addresses and to help determine where connections are
failing. To help locate faults, an engineer can ping end devices, devices located on intermediate points, or
managed switches between two end devices.
Most TCP/IP devices will respond to a ping request, however, it is possible for a device to ignore ping
requests or to have ping responses disabled. The device’s user manual will usually note if pings or ping
requests can be turned off.
5.1.3 Switch Configuration and Management
EtherNet/IP networks can be optimized to enhance their performance. Most industrial EtherNet/IP
deployments that share the network with other kinds of traffic will require some level of switch
configuration. The configuration process also enables the network to insure a high level of resiliency,
deterministic behavior, and a high degree of security with appropriate access for authorized users. This
process will increase the level of access an authorized user has, potentially allowing for monitoring and
configuration of devices from anywhere in the world. It also reduces costs as it leverages the existing
Ethernet infrastructure to deliver multiple services and new applications.
Managed vs. Unmanaged Devices
The broad definition of a managed device encompasses any network element that can be configured
to improve performance and/or can be accessed remotely to gather metrics on it. Switches that can
be configured and accessed remotely are normally referred to as managed switches. Network
switches that are not configurable, and therefore cannot be optimized, are generally referred to as
unmanaged switches.
In terms of the EtherNet/IP infrastructure, managed devices may include very basic functions such as
simple network utilization (RMON) to more critical settings that determine who has access to a given set
of services or traffic (security). It can also include which traffic should be prioritized (QoS), what amount
of bandwidth should be allocated to a given port or application to assure high availability of the network
(preventing potential critical situations like a broadcast storm from interfering with control messaging),
how to deal with multicast traffic, etc. The level of management is commensurate with the set of features
that may be optimized or the metrics that may be gathered.
Many network elements, such as routers and switches that have been designed as managed devices, are
configured using Simple Network Management Protocol (SNMP), often with graphical user interfaces.
This is actually no different from programming a PLC or any other control element that has some level of
embedded programmable logic.
Most vendors of Ethernet switches provide some graphical interface utility that can be used for accessing
the device. Many of the vendors also provide a web browsing interface allowing for the configuration of
the devices through the network by pointing the browser to the switch’s IP address. This presumes that
the IP address has already been configured into the device.