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switch block
The switch block is a combination of Layer 3 switches and
Layer 3 routers. The Layer 2 switches connect users in the wiring closet into
the Access layer and provide 10 or 100Mbps dedicated connections.
1900/2820 and 2900 Catalyst switches can be used in the switch block.
switched Ethernet
Device that switches Ethernet frames between seg-
ments by filtering on hardware addresses.
switched LAN
Any LAN implemented using LAN switches. See also:
LAN switch.
The central functional block of any switch design; respon-
sible for buffering and routing the incoming data to the appropriate output
synchronous transmission
Signals transmitted digitally with precision
clocking. These signals have identical frequencies and contain individual
characters encapsulated in control bits (called start/stop bits) that designate
the beginning and ending of each character. See also: asynchronous trans-
and isochronous transmission.
T reference point
Used with an S reference point to change a 4-wire ISDN
network to a 2-wire ISDN network.
Digital WAN that uses 24 DS0s at 64K each to create a bandwidth of
1.536Mbps, minus clocking overhead, providing 1.544Mbps of usable
Digital WAN that can provide bandwidth of 44.763Mbps.
Terminal Access Control Access Control System: An enhanced
version of TACACS, this protocol is similar to RADIUS. See also: RADIUS.
tag switching
Based on the concept of label swapping, where packets or
cells are designated to defined-length labels that control the manner in which
data is to be sent, tag switching is a high-performance technology used for
forwarding packets. It incorporates Data Link layer (Layer 2) switching and
Network layer (Layer 3) routing and supplies scalable, high-speed switching
in the network core.
Copyright ©2001 SYBEX , Inc., Alameda, CA