NonStop System Glossary

ServerNet extender module (SEM)
Equipment that increases the distance that ServerNet signals can be transmitted over fiber-optic
cables to 40 kilometers. If multimode fiber-optic (MMF) and single-mode fiber-optic (SMF) ServerNet
cables are used in the same system, the SEM converts MMF signals so that they can be transmitted
by SMF ServerNet cables and converts SMF signals so that they can be transmitted by MMF
ServerNet cables.
ServerNet ID
A unique identifier for an addressable unit on a ServerNet communications network. A unit can
have multiple ServerNet node IDs. This ID is used for routing. Each packet has a source ServerNet
node ID and a destination ServerNet node ID. A pair of processors operating in duplex mode
share one ServerNet node ID.
ServerNet LAN Systems Access (SLSA) subsystem
A subsystem of the NonStop operating system for configuration and management of ServerNet
local area network (LAN) objects.
ServerNet link
Two unidirectional point-to-point communication paths, one in each direction, connecting a router
to a ServerNet node or another router. Each ServerNet link contains a transmit channel and a
receive channel.
ServerNet memory interface (SMI)
An application-specific integrated circuit (ASIC) that provides the interface between the
microprocessor and the two ServerNet fabrics and main memory.
ServerNet node
A system in a ServerNet cluster. See also node.
ServerNet node number
A number that identifies a member system in a ServerNet cluster. The ServerNet node number is
a simplified expression of the ServerNet node routing ID. The ServerNet node number is assigned
based on the port to which the node is connected on the cluster switch. The ServerNet node number,
which can be viewed using the Subsystem Control Facility (SCF) or the OSM Service Connection,
is unique for each node in a ServerNet cluster.
ServerNet node routing ID
A bit field used to route ServerNet packets across the external ServerNet X and Y fabrics. The
ServerNet node routing ID occupies a portion of the ServerNet ID, and it is unique for each member,
or node, in a ServerNet cluster. This term is the fully qualified form of node routing ID. The node
routing ID determines the node to which a ServerNet packet is routed.
SERVERNET object type
In the Kernel subsystem, the object type for either the $ZSNET ServerNet subsystem manager
process or the ServerNet X fabric or Y fabric.
ServerNet packet
The unit of transmission in a ServerNet communications network. A ServerNet packet consists of
a header, a variable-size data field, and a 32-bit cyclic redundancy check (CRC) checksum covering
the entire packet. The header contains fields for control, virtual memory address, and destination
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