Cisco Universal Broadband Router uBR10012 Hardware Installation Manual page 266

Glossary
S
Segmentation and reassembly. One of the two sublayers of the AAL common part convergence
SAR
sublayer, responsible for dividing (at the source) and reassembling (at the destination) the protocol data
units (PDUs) passed from the convergence sublayer. The SAR sublayer takes the PDUs processed by
the convergence sublayer and, after dividing them into 48-byte pieces of payload data, passes them to
the ATM layer for further processing. See also AAL.
small formfactor pluggable (module) as in
SFP
See SR.
Short reach
See SNMP.
Simple Network
Management
Protocol
See SMF.
Single-mode fiber
Single-mode fiber. Fiber-optic cabling with a narrow core that allows light to enter only at a single
SMF
angle. Such cabling has higher bandwidth than multimode fiber, but requires a light source with a
narrow spectral width (for example, a laser). Also called monomode fiber. See also
Simple Network Management Protocol. Network management protocol used almost exclusively in
SNMP
TCP/IP networks. SNMP provides a means to monitor and control network devices, and to manage
configurations, statistics collection, performance, and security. See also SNMP2.
SNMP Version 2. Version 2 of the network management protocol. SNMP2 supports centralized as well
SNMP2
as distributed network management strategies, and includes improvements in the SMI, protocol
operations, management architecture, and security. See also SNMP.
Synchronous Optical Network. High-speed synchronous network specification developed by Bellcore
SONET
and designed to run on optical fiber. STS-1 is the basic building block of SONET. It was approved as
an international standard in 1988.
Short reach. SONET/SDH specification for transmit power and receive sensitivity that achieves a
SR
1.2-mile (2 km) reach.
A type of RAM that retains its contents for as long as power is supplied. SRAM does not require
SRAM
constant refreshing, like DRAM. Compare with DRAM.
Subrate DS3
A generic term to describe a process in which the bandwidth of a clear channel DS3 is limited to a lower
rate. Several proprietary formats exist.
See SONET.
Synchronous
Optical Network
T
Digital WAN carrier facility. T1 transmits DS1-formatted data at 1.544 Mbps through the telephone
T1
switching network.
Cisco uBR10012 Universal Broadband Router Hardware Installation Guide
GL-12
GBIC
Multimode fiber.
OL-18259-09