CCNA Cisco Certified Network Associate Study Guide - FTP Server

Glossary 707
SPID Service Profile Identifier: A number assigned by service providers or
local telephone companies and assigned by administrators to a BRI port.
SPIDs are used to determine subscription services of a device connected via
ISDN. ISDN devices use SPID when accessing the telephone company switch
that initializes the link to a service provider.
split horizon Useful for preventing routing loops, a type of distancevector
routing rule where information about routes is prevented from
leaving the router interface through which that information was received.
spoofing 1) In dial-on-demand routing (DDR), where a circuit-switched
link is taken down to save toll charges when there is no traffic to be sent,
spoofing is a scheme used by routers that causes a host to treat an interface
as if it were functioning and supporting a session. The router pretends to
send “spoof” replies to keepalive messages from the host in an effort to convince
the host that the session is up and running. See also: DDR. 2) The
illegal act of sending a packet labeled with a false address, in order to deceive
network security mechanisms such as filters and access lists.
spooler A management application that processes requests submitted to it
for execution in a sequential fashion from a queue. A good example is a print
spooler.
SPX Sequenced Packet Exchange: A Novell NetWare transport protocol
that augments the datagram service provided by Network layer (Layer 3)
protocols, it was derived from the Switch-to-Switch Protocol of the XNS
protocol suite.
SQE Signal Quality Error: In an Ethernet network, a message sent from a
transceiver to an attached machine that the collision-detection circuitry is
working.
SRB Source-Route Bridging: Created by IBM, the bridging method used in
Token-Ring networks. The source determines the entire route to a destination
before sending the data and includes that information in route information
fields (RIF) within each packet. Contrast with: transparent bridging.
SRT source-route transparent bridging: A bridging scheme developed by
IBM, merging source-route and transparent bridging. SRT takes advantage of
both technologies in one device, fulfilling the needs of all end nodes. Translation
between bridging protocols is not necessary. Compare with: SR/TLB.