Session Announcement Protocol. Used with multicast protocols to handle session conference announcements.
SCB
System Control Board. On an M40 router, the part of the Packet Forwarding Engine that performs route lookups, monitors system components , and controls FPC resets.
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]
SFM
Switching and Forwarding Module. On an M160 router, a component of the Packet Forwarding Engine that provides route lookup, filtering, and switching to FPCs.
shortest- path -first algorithm
See [SPF]
signaled path
In traffic engineering, an explicit path; that is, a path determined using RSVP signaling. The ERO carried in the packets contains the explicit path information.
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.
SSB
System and Switch Board. On an M20 router, Packet Forwarding Engine component that performs route lookups and component monitoring and monitors FPC operation.
SSH
Secure shell. Software that provides a secured method of logging in to a remote network system.
SSRAM
Synchronous Static Random Access Memory.
static LSP
See [static path]
static path
In the context of traffic engineering, a static route that requires hop-by-hop manual configuration. No signaling is used to create or maintain the path. Also called a static LSP.
STM
Synchronous Transport Module. CCITT specification for SONET at 155.52 Mbps.
strict
In the context of traffic engineering, a route that must go directly to the next address in the path.
STS
Synchronous Transport Signal. Synchronous Transport Signal level 1. Basic building block signal of SONET, operating at 51.84 Mbps. Faster SONET rates are defined as STS- n, where n is a multiple of 51.84 Mbps.
See also [SONET]
stub area
In OSPF, an area through which, or into which, AS external advertisements are not flooded.
subnet mask
Number of bits of the network address used for host portion of a Class A, Class B, or Class C IP address.
summary link advertisement
OSPF link-statement advertisement flooded throughout the advertisement's associated areas by area border routers to describe the routes that they know about in other areas.
sysid
System identifier. Portion of the ISO nonclient peer. The sysid can be any 6 bytes that are unique throughout a domain.