SWAN Concentrator Installation and Support Guide

Glossary
SWAN Concentrator Installation and Support Guide—429391-006
Glossary-2
data circuit-terminating equipment (DCE)
data circuit-terminating equipment (DCE). A modem to which the SWAN concentrator
connects. The SWAN concentrator is a DTE. See also data terminal equipment (DTE)
and modem.
data link control (DLC) task. WAN DLC tasks support the equivalent to level 2 of the
ISO/OSI Seven-Layer Model. The WAN DLC tasks execute in the SWAN concentrator
communications line interface processor (CLIP). Each DLC task controls one line
interface. More than one type of DLC task can run in the same CLIP. Two DLC tasks
run in each CLIP.
data terminal equipment (DTE). The SWAN concentrator is a DTE and connects to a
modem (the DCE). See also customer replaceable unit (CRU) and modem.
download. The process of transferring files from disk storage on the Tandem server into the
CLIP. See also communications line interface processor (CLIP) and FIRMUP process.
essential flash PROM. The essential flash PROM contains code that is used for the
initialization of each CLIP and for subsequent communication with the WAN subsystem
software residing on the NonStop S-series server. The essential flash PROM consists
mainly of two modules, the SWAN firmware file and the FRU information record (FIR).
See also nonessential flash PROM.
Ethernet. A form of local area network (LAN). The Ethernet data transfer rate is typically 10
Megabits per second (Mbps).
field replaceable unit (FRU). A component, an assembly, or a subassembly that can be
installed and removed only by Tandem-trained personnel using special tools, such as a
Torx screwdriver. Some FRUs have maintenance procedures, such as cleaning
procedures, that do not require any special personnel training by Tandem.
FIRMUP process. A process that updates the SWAN concentrator CLIP flash PROM in a
power-fail fault-tolerant manner by downloading the SWAN firmtask file.
firmware. An ordered set of instructions and data stored in a way that is functionally
independent of main storage; for example, microprograms stored in the nonvolatile
ROM. The two types of firmware are (a) read-only, which is burned into memory chips
at the time of their manufacture, and (b) updatable, which resides in writable memory
(FLASH PROM or EEPROM). See also essential flash PROM, nonessential flash
PROM, and FIRMUP process.
FLASH memory. Software components are stored on each CLIP on the SWAN
concentrator in either the programmable flash memory (flash PROM) on in DRAM. The
flash PROM is divided into two parts, essential flash PROM and non-essential flash
PROM. See also essential flash PROM, nonessential flash PROM, or essential flash
PROM.
FLASH PROM. A type of programmable read-only memory (PROM) that is electrically
reprogrammable in circuit but large parts of which must be erased before new data is
programmed in.