Cisco 10000 Series Configuration Manual page 353

Differentiated service code point. Specifies a precedence value for handling packets belonging to the
DSCP
specified class.
Data service unit. Device used in digital transmission that adapts the physical interface on a DTE device
DSU
to a transmission facility such as T1 or E1. The DSU is also responsible for such functions as signal
timing. Often used with CSU, as in CSU/DSU. See also CSU.
E
See ESR.
Edge Services
Router
Extended superframe. Framing type used on T1 circuits that consists of 24 frames of 192 bits each, with
ESF
the 193rd bit providing timing and other functions. ESF is an enhanced version of SF. See also SF.
Edge Services Router. A router that aggregates traffic from thousands of low- and medium-bandwidth
ESR
subscriber connections and routes it on a few high-bandwidth connections to the Internet core.
Baseband LAN specification. Ethernet networks use CSMA/CD and run over a variety of cable types
Ethernet
at 10 Mbps, 100 Mbps, or 1000 Mbps. Ethernet is similar to the IEEE 802.3 series of standards. See
also
See ESF.
Extended
Superframe Format
F
See FDL.
Facility data link
Any of a number of 100 Mbps Ethernet specifications. Fast Ethernet offers a speed increase 10 times
Fast Ethernet
that of the 10BaseT Ethernet specification, while preserving qualities such as frame format, MAC
mechanisms, and MTU. Existing 10BaseT applications and network management tools can be used on
Fast Ethernet networks. The Fast Ethernet specification is based on an extension to the IEEE 802.3
specification. Compare with
Facility data link. Embedded communications channel in ESF DS1 framing. Used to convey both
FDL
bit-oriented and message-oriented signals.
Nonvolatile storage that can be electrically erased and reprogrammed so that software images can be
Flash memory
stored, booted, and rewritten as necessary. Flash memory was developed by Intel and is licensed to
other semiconductor companies.
Frame Relay Industry-standard, switched data link layer protocol that handles multiple virtual circuits using HDLC
encapsulation between connected devices. Frame Relay is more efficient than X.25, the protocol for
which it is generally considered a replacement.
OL-8834-04
Fast Ethernet, Gigabit Ethernet.
Ethernet and Gigabit Ethernet.
Cisco 10000 Series Router Line Card Configuration Guide
Glossary
GL-3