Glossary S
Centillion 1200N ATM Switch User Manual B-67
NTP 297-8103-903
SCCP
Signaling Connection and Control Part: A SS7 protocol that provides additional
functions to the Message Transfer Part (MTP). It typically supports Transaction
Capabilities Application Part (TCAP).
Scope
Defines the level of advertisement for an address. The level is a level of a peer group
in the PNNI routing hierarchy.
SCP
Service Control Point: A computer and database system which executes service
logic programs to provide customer services through a switching system. Messages
are exchanged with the SSP through the SS7 network.
SCR
Sustainable Cell Rate: An upper bound on the conforming average rate of an ATM
connection over time scales which are long relative to those for which the PCR is
defined. Enforcement of this bound by the UPC could allow the network to allocat e
sufficient resources, but less than those based on the PCR, and still ensure tha t the
performance objectives (e.g., for Cell Loss Ratio) can be achieved.
SDH
Synchronous Digital Hierarchy: The ITU-TSS International standard for
transmitting information over optical fiber.
SDT
Structured Data Transfer: An AAL1 data transfer mode in which data is struct ured
into blocks which are then segmented into cells for transfer.
SDU
Service Data Unit: A unit of interface information whose identity is preserved from
one end of a layer connection to the other.
SE
Switching Element: Switching Element refers to the device or network node which
performs ATM switching functions based on the VPI or VPI/VCI pair.
SEAL
Simple and Efficient Adaptation Layer: An earlier name for AAL5.