Route Switch Module (RSM)
Cisco’s first multiprotocol multilayer switch module, which utilizes the full support of the Cisco IOS
for performing Layer 3 routing from a slot internally on a Layer 2 switch. This module provides for
interVLAN connectivity.
Routing Information Field (RIF)
A field on Source Route Bridge Token Ring frames that contains information about the rings and
bridges that the frame must travel to the destination interface.
Routing Information Protocol (RIP)
Protocol that uses hop counts as a routing metric to control the direction and flow of packets between
routers and switches on an internetwork.
Runtless switching
A switching method in which the switch reads the first 64 bytes to verify that there is no corruption of
the packet. If there is corruption, a preset maximum of errors changes the switching type from
cut−through switching to store−and−forward switching. Also known as FragmentFree switching.
S
Secure Data Exchange (SDE) Protocol Data Unit
A field (part of the 802.10 header) that copies the encrypted Protected Header for security purposes to
help guarantee against tampering with the frame. Also known as the Clear Header.
Security Association Identifier (SAID)
One of the three values that make up a Clear Header on the FDDI frame type. It is used for security
for the Clear Header. The Clear Header contains a SAID, Link Service Access Point (LSAP), and
Management Defined field (MDF).
Sequenced Packet Exchange (SPX)
Protocol used in conjunction with IPX when connection−oriented delivery is required. It is used
mainly in NetWare network environments.
server A resource node that fulfills service requests for demand nodes. Usually referred to by the type of
service it performs, such as file server, email server, or print server.
service access point (SAP)
A field in a frame that tells the receiving host which protocol the frame is intended for.
Service Advertising Protocol (SAP)
NetWare protocol used on an IPX network. SAP maintains server information tables, listing each
service that has been advertised to it, and provides this information to any nodes attempting to locate a
service.
Service Advertising Protocol agent (SAP agent)
Router or other node on an IPX network that maintains a server information table. This table lists each
service that has been advertised to it and provides this information to any nodes attempting to locate a
service.
session The dialog that exists between two computers.
Session layer
The fifth layer of the OSI Reference Model, which establishes, manages, and terminates sessions
between applications on different nodes.
shared system
The infrastructure component routed directly into the backbone of an internetwork for optimal
systems access. It provides connectivity to servers and other shared systems.
shielded twisted−pair (STP)
Twisted−pair network cable that has shielding to insulate the cable from electromagnetic interference.
Simple Network Management Protocol (SNMP)
A protocol used with TCP/IP networks to provide network devices with a method to monitor and
control network devices. It is used to manage configurations, statistics collection, performance, and
security, and to report network management information to a management console that is a member of
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