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Chapter 5. Ethernet Global Data
GFK-2224Q January 2017 73
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Using EGD groups or broadcasting to subnets. Rather than producing a directed exchange to several
destinations, a single exchange can contain all the data and each consumer can transfer only the data it
needs from the exchange.
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Adding another Ethernet Interface module to the rack and spreading the EGD exchanges.
Using Ethernet Global Data in a Redundancy System
When configured for Redundant IP operation, the active unit produces all EGD exchanges to the network. The
backup unit produces only EGD exchanges that have their Produce in Backup Mode property set to True. When
the active Ethernet interfaces changes to backup, it stops production of all EGD exchanges except those that
are configured to produce in backup mode.
When configured for Redundant IP operation, the active and backup Ethernet interfaces should be configured
to consume EGD exchanges via multicast host groups or the local subnet broadcast address. This permits both
the active and backup units to receive the latest data from the network. Unicast operation is not
recommended. The backup unit does not consume exchanges at the Redundant IP address.
For additional information about redundancy systems, refer to
“Ethernet Redundancy Operation”
in Chapter 1.
5.3 Sending an Ethernet Global Data Exchange to Multiple
Consumers
There are two ways to send an EGD Exchange to multiple consumers at the same time: by Multicasting it to a
predefined group of consumers or by Broadcasting it to all of the consumers on a subnet. Both methods allow
many consumer devices to simultaneously receive the same data from one producing EGD device. If an
exchange is Broadcast or Multicast, the same exchange must be configured at the producer and at each
consumer. Each consumer can use all of the data or just a selected portion, as configured for the consumed
exchanges.
For more information about Multicasting and Broadcasting, refer to Chapter 13 Network Administration.
Multicasting Ethernet Global Data
If more than one device on the network should consume a Global Data exchange, those devices can be set up
as a group. The network can include up to 32 numbered groups. Groups allow each sample from the producer
to be seen simultaneously by all consumers in the group.
A device can belong to more than one group, as illustrated below. In the following example, device 10.0.0.2
consumes exchanges from Group 2 and from Group 1.
Group 2
I0.0.0.1 I0.0.0.2
I0.0.0.6 I0.0.0.7 I0.0.0.8
I0.0.0.3 I0.0.0.4
I0.0.0.5
Group 1
Group 2
Figure 36: Grouping of Devices for Ethernet Global Data Multicasting