Cisco Systems 8600 Series manual RS-449, SAR Segmentation and Reassembly, SCC System Clock Card

RS-449

The physical interface for the RS422 and R423 electrical interfaces. Contains the Processor Controller Card and the PCC utility bus, and provides system timing and control via the system bus.

S

SAR (Segmentation and Reassembly)

The process of breaking a dataframe containing data from a number of virtual paths or circuits apart so that the individual paths/circuits can be switched by reassembling the data into a new frame with a different sequence.

SCC (System Clock Card)

An IPX backcard that works in conjunction with the NPC. The SCC provides a centralized clock generation function and provides serial and LAN port interfaces.

SCM (System Clock Module)

An IGX backcard that works in conjunction with the NPM. The SCM provides a centralized clock generation function and provides serial and LAN port interfaces.

SCR (Sustainable Cell Rate)

Rate above which incoming cells are either tagged or discarded.

SDP (Synchronous Data PAD)

An IPX front card that supports one to four medium speed, synchronous data channels.

SDI (Synchronous Data Interface)

The back card for the SDP (IPX switch) or HDM (IGX switch) cards. The SDI is available with V.24, X.21, and V.35 interfaces.

seamless international network

An IPX network that is configured to carry traffic over international borders (E1-T1 or T1-E1)—see also gateway.

Simple Gateway

Refers to FastPacket to ATM interworking with respect to the IPX and IGX nodes. In the simple gateway mode, FastPackets are encapsulated in their entirety into cells. Compare with complex gateway.

SIU (Serial Interface Unit)

A set of circuits common to all BPX cards used for transmitting and receiving via the crosspoint switch.

Soft PVC

A PVC in the INS Dial-Up Frame Relay application that is dormant in the networks database until it is activated by a call into the network by a user.

spanning tree

An IPX network topology in which there is only one path available between any two sources in a frame relay multicast group. Spanning trees are required to prevent frames broadcast from a single source to multiple receptors from circulating endlessly around the network a result of frame relay circuits not having properly closed loops.

E-16Cisco BPX 8600 Series Reference