DESCRIPTION AND OPERATION
NIS MODULE DATA INTEGRITY
I-E96-607A
2 - 3
NIS MODULE DATA INTEGRITY
Retry Logic
If, on the first message transmission, the NIS module does not
receive an acknowledge (ACK) or busy negative acknowledge
(NAK) from the destination node, it transmits the message
again up to 11 times. If, after this series of retries, there is still
no response, the destination node is marked off-line and the
NIS module informs the transfer module of the negative
acknowledge.
Node Status Table
The NIS module maintains an internal table of system-wide
status such as off-line and busy nodes. The NIS module relays
node status changes to the transfer module. When the NIS
module periodically polls nodes, it updates this table
accordingly.
Polling
The NIS module uses the information in its status table for
polling purposes. As it scans the status table, it picks out des-
tinations targeted for multicast messages that have been
marked off-line or busy. After polling the destination, the NIS
module updates its table and forwards pertinent information to
the transfer module.
INIIT02 INFI-NET TO INFI-NET TRANSFER MODULE
The INIIT02 module passes exception reports, and control and
configuration data between the central INFI-NET loop and a
satellite INFI-NET loop. Operation of the interface is transpar-
ent to the user. The INIIT02 modules take the responsibility of
retrying failed messages and informing the original source of
any failure. Other INFI-NET communication modules interact
with the INIIT02 module within the node status protocol rules
of INFI-NET. The interface generates on-line, off-line and busy
status for nodes on other loops and tracks node status for
every node on the local loop.
Blown Fuse Detection
The INIIT02 module can detect a blown fuse on the loop termi-
nation unit or module. If the loop termination unit or module
blows a fuse, or power is removed from the loop termination
unit or module, the INIIT02 module status LED turns red and
CPU LEDs three through six turn on. This feature is available
only on NIS modules with firmware revision E.1 or later and
INIIT02 modules with firmware revision B.1 or later.
