| |
|
S |
| SAA |
 |
Systems Application Architecture, an IBM architecture
designed to allow all of IBM products to communicate
and function together. |
| SAC |
|
Single-Attached Concentrator; also Security Access
Control. See DAC. |
| SAP |
|
Service
Access Point |
| SAPI |
|
Service
Access Point Identifier |
| SAS |
|
Single-Attached
Station. See DAS. |
| SASE |
|
Specific
Application Service Element |
| SASs |
|
Single
Attachment Stations |
| SCR |
|
Sustained
Cell Rate |
| SD |
|
Standard Density |
| SDH |
|
Synchronous Digital Hierarchy |
| SDLC |
|
Synchronous
Data Link Control (IBM version of HDLC), IBM communications
line discipline or protocol associated with SNA, SDLC
provides for control of a single communications line
or link, accommodates a number of network arrangements
and operates in half- or full-duplex over private or
switched facilities. |
| SDP |
|
Session
Description Protocol |
| Serial
interface |
|
Interface
which requires serial transmission, or the transfer
of information in which the bits composing
a character are sent sequentially. Implies only a single
transmission channel. |
| Server |
|
A
computer that provides resources to be shared on the
network, such as files (file server) or terminals (terminal
server). |
| |
|
|
| Session |
|
A
connection to a network service. |
| Session
Layer |
|
OSI
layer that provides means for dialogue control between
end systems. |
| SGML |
|
Standardised
Graphics Mark-up Language |
| SHDSL |
|
Single-pair
High-speed Digital subscriber Line |
| SID |
|
Silence
Insertion Descriptor |
| Single
mode fiber |
|
Fiber
with a relatively narrow diameter, through which only
one mode will propagate. Carries higher bandwidth than
multimode fiber, but requires a light source with a
narrow spectral width. |
| SIP |
|
Session
Initiation Protocol |
| SLIP |
|
Serial Line Interface Protocol, internet protocol used
to urn IP over serial lines such as telephone circuits
or RS-232 cables interconnecting two systems. SLIP
is now being replaced by PPP.
Serial
Line Internet Protocol, a protocol for running TCP/IP
over serial lines. |
| SMC |
|
Service
Management Centre |
| SMDS |
|
Switched Multimegabit Data Service, high-speed, packet-switched,
connectionless WAN service. |
| SME |
|
Small & Medium
Enterprise |
| SMF |
|
Single Mode optical Fiber |
| SML |
|
Service
Management Layer |
| SMT |
|
Station
Management, that part of the FDDI specification that
manages stations on the ring, as defined by the
X3T9.5 specification. |
| SMTP |
|
Simple Mail Transfer Protocol, protocol governing mail
transmissions; defined in RFC 821, with associated
message format descriptions in RFC 822. |
| SN |
|
Sequence
number |
| SNA |
|
Systems
Network Architecture, IBM's proprietary network architecture
for mainframe communications. |
| SNAP |
|
Sub
Network Access Protocol, internet protocol that operates
between a network entity in the subnetwork and a network
entity in the end system and specifies
a standard method of encapsulating IP datagrams and ARP messages on IEEE
systems. |
| SNMP |
|
Simple
Network Management Protocol, preferred network management
system for TCP/IP-based Internets. Allows
a TCP/IP host running an SNMP application to query
other nodes for network-related statistics and error
conditions. The other hosts, which provide SNMP agents,
respond to these queries and allow a single host to
gather network statistics from many other network nodes. |
| SNP |
|
Subnetwork Protocol, (TCP/IP) Protocol residing in
the subnetwork layer below IP that provides data transfer
through the local subnet. In some systems, an adapter
module must be inserted between Ip and the Subnetwork
Protocol to reconcile their dissimilar interfaces. |
| SNR |
|
Signal
to Noise Ratio |
| |
|
|
| SOC |
|
System
On a Chip |
| SOHO |
|
Small Office Home Office |
| SONET |
|
Synchronous Optical Network, Standard for digital transmission
at rates from 51.84 Mbps to beyond 2.4 Gbps (gigabits
per second). |
| SONI |
|
SDH/SONET
Interface module
SDH/SONET
Optical Network Interface |
| Source
code |
|
Programs
in an uncompiled or unassembled form. |
| Spanning
tree |
|
An
algorithm used by bridges to create a logical topology
that connects all network segments and ensures
that only one path exists between any two stations. |
| Split
horizon |
|
Routing
technique where information about routes is prevented
from exiting router interfaces through
which that information was received. Useful in preventing
routing loops. |
| SPP |
|
Sequenced
Packet Protcol |
| SPX |
|
Sequenced Packet Exchange |
| SQE |
|
Signal
Quality Error, transmission sent by a transceiver back
to the controller to let the controller know whether
the collision circuitry is functional. |
| SR |
|
Source
Routing |
| SR-ID |
|
SubRack IDentifier |
| SRT
Bridge |
|
Source
Routing Transparent, proposed IEEE 802.1 bridge to
combine source routing (in which the source
end system provides routing information) with transparent
bridging (in which the bridge makes independent message
handling choices and therefore is transparent to the
message source and destination. |
| SSAP |
|
Source Service Access Point |
| SSCS |
|
Service
Specific Convergence Sublayer |
| STA |
|
Spanning
Tree Algorithm, function of managed bridges which allows
redundant bridges to be used for network
resilience, without the broadcast storms associated
with looping. If a bridge fails, a new path to a redundant
bridge is opened. |
| Star
topology |
|
Network
configuration where all the nodes are connected to
a central point via individual cables. |
| Static
routing |
|
System
in which routing information is manually entered into
the routing table. |
| STB |
|
Set
Top Box |
| STF |
|
STart
Field |
| STM |
|
Synchronous
Transfer Mode
Synchronous
Transport Module (i.e. STM-1) |
| |
|
|
| Store
and forward |
|
Technique
for examining incoming packets on an Ethernet switch
or bridge whereby the whole packet
is read before forwarding or filtering takes place.
Store and forward is a slightly slower process than
cut-through, but it does ensure that all bad or misaligned
packets are eliminated from the network by the switching
device. |
| STP |
|
Shielded Twisted Pair, common transmission medium which
consists of a Receive (RX) and a Transmit (TX) wire
twisted together to reduce crosstalk. The twisted pair
is shielded by a braided outer sheath. |
| SPX |
|
Sequential Packet exchange, Novell's implementation
of SPP (sequential packet
protocol). |
| SQE |
|
Ethernet-defined
signal quality test function, frequently called "heartbeat." |
| STUN |
|
Simple Traversal of UDP throught NATs. |
| Subnetwork |
|
Collection of OSI end systems and intermediate systems
under the control of one administrative domain and
using a single network access protocol. For example,
private X25 networks, a series of bridged LANs. Compare
Autonomous System. |
| SVC |
|
Switched Virtual Circuit, virtual circuit that can
be dynamically established
on demand. |
| Switch |
|
Multiport Ethernet device designed to increase network
performance by allowing only essential traffic on the
attached individual Ethernet segments. Packets are
filtered or forwarded based upon their source and destination
addresses. |
| Switched
56 |
|
Switched
data transmission service at 56 Kbps (as opposed to
service
on dedicated leased lines). |
| Synchronous |
|
Form of usually high-speed data communication that
uses synchronization bytes instead of start or stop
bits to tell the receiving device about the coming
transmission. More complex than Asynchronous Transmission. |
| |
|
|
