User Manual

Glossary
231
Glossary
RFI Radio frequency interference. Interference from high-frequency electromagnetic waves
emanating from electronic devices.
RIP Routing Information Protocol. Distance-vector interior gateway protocol that makes routing
decisions based on hop count.
routing domain See AS.
Routing Engine Architectural portion of the router that handles all routing protocol processes, as well as other
software processes that control the router’s interfaces, some of the chassis components,
system management, and user access to the router.
routing table Common database of routes learned from one or more routing protocols. All routes are
maintained by the JUNOS routing protocol process.
rpd JUNOS software routing protocol process (daemon). User-level background process
responsible for starting, managing, and stopping the routing protocols on a Juniper Networks
router.
RPM Reverse path multicasting. Routing algorithm used by DVMRP to forward multicast traffic.
RSVP Resource Reservation Protocol. Resource reservation setup protocol designed to interact with
integrated services on the Internet.
S
SAP Session Announcement Protocol. Used with multicast protocols to handle session conference
announcements.
SAR Segmentation and reassembly. Buffering used with ATM.
SDH Synchronous Digital Hierarchy. CCITT variation of SONET standard.
SDP Session Description Protocol. Used with multicast protocols to handle session conference
announcements.
SDRAM Synchronous dynamic random access memory.
secure shell See SSH.
shortest-path-first
algorithm
See SPF.
simplex interface An interface that assumes that packets it receives from itself are the result of a software
loopback process. The interface does not consider these packets when determining whether
the interface is functional.
SNMP Simple Network Management Protocol. Protocol governing network management and the
monitoring of network devices and their functions.
SONET Synchronous Optical Network. High-speed (up to 2.5 Gbps) synchronous network
specification developed by Bellcore and designed to run on optical fiber. STS-1 is the basic
building block of SONET. Approved as an international standard in 1988. See also SDH.
SPF Shortest-path first, an algorithm used by IS-IS and OSPF to make routing decisions based on
the state of network links. Also called the Dijkstra algorithm.