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Glossary
standard IP access list
IP access list that uses only
the source IP addresses to filter a network.
standard IPX access list
IPX access list that uses
only the source and destination IPX address to filter a
network.
star topology
A LAN physical topology with end-
points on the network converging at a common cen-
tral switch (known as a hub) using point-to-point
links. A logical ring topology can be configured as a
physical star topology using a unidirectional closed-
loop star rather than point-to-point links. That is, con-
nections within the hub are arranged in an internal
ring. See also: bus topology and ring topology.
startup range
If an AppleTalk node does not have a
number saved from the last time it was booted, then
the node selects from the range of values from 65280
to 65534.
state transitions
Digital signaling scheme that
reads the "state" of the digital signal in the middle of
the bit cell. If it is five volts, the cell is read as a one. If
the state of the digital signal is zero volts, the bit cell is
read as a zero.
static route
A route whose information is purpose-
fully entered into the routing table and takes priority
over those chosen by dynamic routing protocols.
static VLANs
Static VLANs are manually config-
ured port-by-port. This is the method typically used in
production networks.
statistical multiplexing
Multiplexing in general is
a technique that allows data from multiple logical
channels to be sent across a single physical channel.
Statistical multiplexing dynamically assigns band-
width only to input channels that are active, optimiz-
ing available bandwidth so that more devices can be
connected than with other multiplexing techniques.
Also known as statistical time-division multiplexing
or stat mux.
STM-1
Synchronous Transport Module Level 1. In
the European SDH standard, one of many formats
identifying the frame structure for the 155.52Mbps
lines that are used to carry ATM cells.
store-and-forward packet switching
A technique
in which the switch first copies each packet into its
buffer and performs a cyclical redundancy check
(CRC). If the packet is error-free, the switch then
looks up the destination address in its filter table,
determines the appropriate exit port, and sends the
packet.
STP
(1) Shielded Twisted Pair: A two-pair wiring
scheme, used in many network implementations, that
has a layer of shielded insulation to reduce EMI. (2)
Spanning-Tree Protocol.
stub area
An OSPF area carrying a default route,
intra-area routes, and interarea routes, but no external
routes. Configuration of virtual links cannot be
achieved across a stub area, and stub areas are not
allowed to contain an ASBR. See also: non-stub area,
ASBR,
and OSPF.
stub network
A network having only one connec-
tion to a router.
STUN
Serial Tunnel: A technology used to connect
an HDLC link to an SDLC link over a serial link.
subarea
A portion of an SNA network made up of a
subarea node and its attached links and peripheral
nodes.
subarea node
An SNA communications host or
controller that handles entire network addresses.
subchannel
A frequency-based subdivision that cre-
ates a separate broadband communications channel.
subinterface
One of many virtual interfaces avail-
able on a single physical interface.
subnet
See: subnetwork.
subnet address
The portion of an IP address that is
specifically identified by the subnet mask as the sub-
network. See also: IP address, subnetwork, and subnet
mask.
subnet mask
Also simply known as mask, a 32-bit
address mask used in IP to identify the bits of an IP
address that are used for the subnet address. Using a
mask, the router does not need to examine all 32 bits,
only those selected by the mask. See also: address
mask
and IP address.
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