IBM 300 Service Manual page 154

two IP hosts over a serial line (for example, an
RS/EIA-232 connection to a modem over a telephone
line).
SLA. Serial link architecture.
SLIP. Serial line internet protocol.
slot. When configuring an Nways Switch, the slot
parameter indicates the module location (1 to 12) in the
logic subrack.
SNA. Systems Network Architecture.
SNMP. Simple Network Management Protocol.
SONET. Synchronous optical network.
spanning tree. See CP spanning tree.
SRC. System reference code.
SSN. Send sequence number.
station. A microcomputer that is connected to a host
or a network and at which a user can run applications.
STM-1. Synchronous transport module type 1.
STS-3c. Synchronous transport signal type 3
concatenated.
SUB. Subaddress.
subrack. A metallic structure installed in an Nways
Switch rack. A logic subrack holds modules. A power
subrack holds power supply components.
SVC. Switched virtual circuit.
SW. Switch (module).
switch module (SW). A module of the 2220 Model
300 or 500 that interconnects the adapters through an
ATM cell switch. It can have a backup.
switch redrive (SWRD). A module of the 2220 Model
501 that drives the signals from the switch module in
the Model 500 to the adapters of the Model 501. It can
have a backup.
SWRD. switch redrive (module)
switched virtual circuit (SVC). A connection set up
from a calling address to a called address following a
call establishment protocol. It is released when a clear
request signal is received.
synchronous digital hierarchy (SDH). A international
recommendation for the internal operation of carrier
optical networks.
synchronous optical network (SONET). A U.S.
standard for transmitting digital information over optical
E-8
2220 Setup and Service Guide
interfaces. It is closely related to the international
recommendation for synchronous digital hierarchy
(SDH).
T1 standard. A TDM digital transmission service with
a basic rate of 1.544 Mbps. Also called DS-1.
T3 standard. A TDM digital transmission service with
a basic rate of 44.736 Mbps. A T3 line can transport up
to 28 T1 circuits. Also called DS-3.
TCPA. Trunk and control point adapter.
TCP/IP. Transmission Control Protocol/ Internet
Protocol.
TDM. Time division multiplexing.
TE. Terminal equipment.
Telnet. In TCP/IP, an application protocol that allows a
user at one site to access a remote system as if the
display station were locally attached. Telnet uses the
Transmission Control Protocol (TCP) as the underlying
protocol.
time division multiplexing (TDM). The process of
breaking the bandwidth on a communication line into a
number of channels, possibly of different size.
TME. Tivoli Management Environment.
TMN. Telecommunication Management Network.
TPA. Trunk or port adapter.
Transmission Control Protocol/ Internet Protocol
(TCP/IP). A set of communication protocols that
support peer-to-peer connections over both local and
wide area networks.
transport services. Functions that are performed by a
trunk adapter of an Nways Switch to:
v Support the attachment of trunk lines
v Maximize bandwidth utilization
v Guarantee the quality of service of a connection
v Transfer packets between Nways Switches
v Manage logical queues and schedule transmission.
trunk. See logical trunk.
trunk adapter. In an Nways Switch, a module that
provides transport services to one or more trunk lines.
Each trunk adapter is associated with a line interface
coupler (LIC).
trunk line. In a 2220 network, a high-speed line
connecting two Nways Switches. It can be, for example,
a copper cable, optical fiber, or radio wave guide and
can be leased from telecommunication companies.
UBR. Unspecified bit rate. A best effort service with no
quality commitment.