Subject: Flow Control and Test Command

From: [email-masked]
Date: Mon, 10 May 93 07:50:31 EDT

There are two signals, ENTER_BUSY and EXIT_BUSY, for informing the partner
that RNR's are being sent/received. The use of them is implementation
dependent. An ENTER_BUSY could be sent when a RNR is received or when
a RNR is sent. Several problems exist with the signals - the time delay
over the WAN, data already on the pipe, and oscillation around lack of
buffers.

SDLC test commands - Two signals exist for sending a test command from
one side to another over the WAN. They are TEST_REQ and TEST_RSP.
The TEST_REQ requests the receiving side to put a test command to the
device and the TEST_RSP is the response to that TEST_REQ. The TEST_REQ
does not have data associated with it. It is up to the side that
receives the TEST_REQ to add the data. The TEST_RSP also does not have
data nor any indicator to say if it was successful - data compare - or
not. It just says the test command was answered.
Note that this is special purpose and normal test_req and test_rsp never
get off the local DLS. If a device sends a test command to DLS, it is
returned by the local DLS and never goes over the WAN. The TEST_REQ and
TEST_RSP described are used by APPN for testing a circuit and measuring
the response time.

How about a naming convention for the two sides. Currently they are called
Blue and Gray. Any suggestions?
Dennis