Expand Configuration and Management Manual (H06.21+, J06.10+)

Glossary
Expand Configuration and Management Manual — 529522-013
Glossary - 7
multipacket frame
systems. The Expand subsystem will simultaneously transmit data over all the lines in
the path, increasing overall bandwidth. The Expand subsystem also automatically
reroutes data over remaining lines if one or more lines fail. See also line, path, and
route. Contrast single-line path.
multipacket frame. A data structure that contains multiple Expand packets. The multipacket
frame feature is enabled using the PATHBLOCKBYTES modifier. It should be enabled
when you are sending many small concurrent requests. Contrast variable packet size.
multiple path table (MPT). A table that resides in each processor in each node in an
Expand network. The network routing table (NRT) contains an entry which points to the
MPT. The MPT contains information bout each multi-CPU path in the system. MPT
entries are assigned to specific multi-CPU paths by $NCP. See also multipacket frame.
NAM. See network access method (NAM).
$NCP. See network control process (NCP).
neighbor systems. See Expand neighbors.
NETATM. The protocol used by Expand-over-ATM line-handler processes to provide a QIO-
based interface to send Layer 2 frames over Asynchronous Transfer Mode (ATM)
networks.
NETIP. The protocol used by Expand-over-IP line-handler processes to provide a QIO-
based interface to send Layer 2 frames over Internet Protocol (IP)-based networks.
NETNAM protocol. The protocol used by an Expand line-handler process to communicate
with a network access method (NAM). See also network access method (NAM).
network. Two or more computer systems (nodes) that are connected so that they can
exchange information and share resources.
network access method (NAM). The interface through which an Expand-over-NAM line-
handler process communicates with an X25AM line-handler process or a SNAX/APN
line-handler process, and through which an Expand-over-ServerNet line-handler
process communicates with the ServerNet monitor process ($ZZSCL).
network control process (NCP). A process pair, named $NCP, that runs in each system of
an Expand network. $NCP is responsible for establishing and terminating system-to-
system connections, maintaining network-related system tables (including the network
routing table, NRT), calculating the most efficient way to transmit data to other systems
in the network, monitoring and logging changes in the status of the network and its
systems, informing $NCPs at neighbor systems of changes in line or Expand line-
handler process status, and aborting pending requests when all paths go down. $NCP
uses the services of the network utility process, $ZNUP. See also
network routing table
(NRT) and network utility process.