In many testing situations there is a need to slightly modify the message
exchange on a given interface between two network elements. Examples are:
testing of new functionalities
simulation of malfunctions
interoperability test between equipment of different vendors
The Real Time Frame Drop-Insert function
listens to the data stream in the channel, seen as a sequence of
frames. Each frame consists of one or more headers, one for each
protocol layer, and of payload data.
Typical application scenarios can be:
between BSC and SGSN to test the Frame Relay
protocol layer;
between BSC and BTSM to test the LAPD protocol
layer;
between BSC and TRAU to test the LAPB protocol
layer;
between BSC and MSC to test the MTP protocol
layer.
The Drop Insert feature is protocol stack independent. The LSU can be
programmed to execute the Real Time Frame Drop-Insert at a certain communication
layer. The Real Time Frame Drop-Insert function works on both sides of
a bi-directional data stream as follows:
Removes a whole frame or parts of it (field by field). Both bit streams
and octets can be managed. It can be programmed to remove the payload
data field and only exchange the suite of headers;
Adds full frames or single fields to the data stream, either fixed
values or depending on the values in the stream can be inserted.
