Specifications
Ethernet Loop Testing
Page E-8
E.2.2.5
ReadStatus
The ReadStatus procedure
is
used to read the status of the Loop
server.
procedure ReadStatus
(
war serverstate: (on,off);
var assistancestate: (on,off));
With the following definit-ions:
serverstate
-
the state of the Loop Server.
assistancestate
-
the state of the loop assistance feature, i.e.
determines
if
station is listening for loopback assistance
multicast address.
E.3
Loop Test Examples
The following examples address the application of the Loop Test
functions. They are intended as examples of how a higher level
process can use the facilities. They are intended neither as a
specification for how they must be used nor as an exhaustive test
script.
In the examples, no account is taken of the fact that the Loop Test
functions make only one attempt to transmit a message. To increase
the reliability of the tests, each interface function that fails due
to a communication error should be retried enough times to lessen the
probability that an intermittent error occurred.
E.3.1 Local Control Test Example
In this case,
a
station finds itself unable to communicate with some
other station that
it
has reason to believe should be available. The
following test script can be used
by
the station to check out the
problem itself.
First, LoopDirect is invoked with remoteAddress set at the correct
address of the specific remote station.
If
this test succeeds, the
communication is possible and the problem may have been either
intermittent, the remote station is down, or there is a problem with
message length or data pattern. Different message lengths and/or data
patterns could then be tried.
If LoopDirect results in
a
return indicating failure, next invoke
LoopAssisted, using some other node as assistantAddress (if no
potential assistant
is
known, use LoopDirect with no remoteAddress to
find
a
member of the loopback assistance multicast group).
If
'
LoopAssisted fails, then the assistant cannot communicate with the
remote node, either.
If
a LoopDirect was successfully used to find an