User's Manual Part 2

CHAPTER 5
REPEATING FEATURES
Revised: 25 Jun 04 5-2 EST P/N AA107G
Learning Phase. After an approximate 10-second period after no further additions to the Mac addresses in the repeater
beacons, the Model 195Eg goes into the learning phase. In this phase all Model 195Eg units calculate their routes to the other
Model 195Eg units in the network using the lowest “path cost”, meaning shortest number of hops, back to the Root Bridge.
Note: The Root Bridge in a network should be the Model 195Eg where the majority of the data flow is processed. In Figure 2,
the Root Bridge will be the Water Plant that is transmitting and receiving data from all three remote sites. The user can program
the Root Bridge manually. If the user does not define the Root Bridge, and if there are multiple candidates for the Route Bridge,
Model 195Eg units in the network will pick the unit with the lowest MAC address. See the following section on Root Bridge for
further details.
Blocking and Forwarding Phase. This last phase in the auto-routing process will eliminate any Ethernet data “loops” that can
double the information received at any remote site. For example, looking at Figure 2, Pump Site D has two routes to the Root
Bridge (Water Plant – Site A). The first Route is direct from the Water Plant and the second Route is via the Tank Site B
(Repeater site). In this example the direct link between the two sites is the shortest route (lowest Path Cost) and will be selected
as the primary route or Forward route. The second route (one with the higher Path Cost) that uses the repeater will be
“Blocked”. All routes to the Root Bridge will be evaluated for the site and be Forwarded or Blocked. The average time to
complete all routing phases in a network is approximately 30 seconds.
Root Bridge
For any Access Point Repeater application that has more than two sites, the user needs to set one of the Model 195Eg’s as the
Root Bridge. The Root Bridge should be the Model 195Eg where the majority of the Ethernet data flow is processed. This site
may be the Master location in a SCADA network or could be configured at a repeater site. Selection is important because, all
the Model 195Eg’s that are “NOT” configured as the Root Bridge will select their routing based upon where the Root Bridge is
defined in the network.
The Root Bridge will be selected in one of two ways:
1. Manually by the users. The Root Bridge can be manually set (recommended) during the configuration at AP Repeater
mode. Reference Chapter 4 – AP Repeater Configuration.
2. Automatically by the Model 195Eg. The Model 195Eg units will automatically configure the Root Bridge by selecting the
lowest MAC address of all the Model 195Eg units in the network. This is usually not recommended in large networks,
because adding a new site to the network could adversely change the entire site’s routing scheme.
If you have any question establishing Route Bridges in your network, contact ESTeem Customer Support at 509-735-9092 or e-
mail your application to [e-mail] .