EMS Manual

Burst Detection and Suppression
EMS Manual—426909-005
7-6
Implementing BDS
represents the PU number 1 through 4). In this configuration, a change of state in one
of the lines generates a line event, four PU events, and 128 (4x32) LU events.
However, only the line event requires attention. The other events simply waste
processing time and disk space. BDS can be used here to eliminate most of the 128
LU events, but probably none of the PU events (because there are only four of them).
To accomplish this, you must analyze the event burst that you want to minimize.
Suppose that the 128 LU events are generated over a period of 30 seconds. If N is set
to 10 events, L to 15 bytes, T1 to 30 seconds, and T2 to 60 seconds, the LU burst is
limited to only 10 events, plus the BDS event-detected event that announces the start
of the event burst. L is set to 15 so that the subject of all of the LU events will compare
as equal. The subject of the LU event is the name of the LU. This LU name takes the
form \ABC.$LINEn.#LUpll, where n is the line number, p is the PU number, and ll is
the LU number. For any given line, the LU name is the same for the first 15 characters.
The overall assumption made in this example is that meaningful LU events do not
occur frequently enough to trigger BDS. Because the BDS configuration parameters
assigned to suppress LU events are applied to all events, it must also be assumed that
any other meaningful events will not unintentionally trigger BDS.
Implementing BDS
Using TACL, you can configure and enable BDS several ways, depending on the state
of the collector or distributor.
Implementing BDS From a Primary Collector
To configure and enable BDS in the primary collector ($0), use one of these methods:

While the primary collector is running, use the SUPPRESS ON command of the
EMSCCTRL program to specify and enable BDS directives for the primary
collector. For a detailed description of EMSCCTRL command syntax options, see
Section 13, EMS Programs
.

If the SUPPRESS function of EMSCCTRL has not been specified, use the FILTER
keyword of EMSCCTRL to specify the name of the burst filter that contains the
burst configuration directives.

While $0 is running, invoke a program that uses the SPI interface to modify the
filter criteria (for example, a program that contains an ADD command with the burst
filter as its object).
Implementing BDS From an Alternate Collector
To configure and enable BDS in an alternate collector, use one of these methods:

When the alternate collector is first started, use the SUPPRESS keyword of the
EMSACOLL program to specify the BDS configuration directives. For a detailed
description of EMSACOLL command syntax options, see Section 13, EMS