3Com 3C971-F manual Service bit rate, Signaling

6GLOSSARY

PVC

Permanent Virtual Circuit. An ATM mode in which the communication circuit between two nodes on a network is manually set up and torn down.

SAR

Segmentation and Reassembly. A procedure that breaks down and reassembles variable-length packets from legacy LAN (Ethernet and token ring) applications. The SAR chip set receives protocol data units (PDUs) from the convergence sublayer and divides them into small segments, typically 44 bytes long. Two header bytes and two trailer bytes are added to these segments. The resulting segment is a 48-byte PDU that fits into the payload of an ATM cell.

SDH

Synchronous Digital Hierarchy. A European body of standards that defines all aspects of transmitting and managing digital traffic over optical fiber.

Service bit rate

The bit rate available to a user for the transfer of data over the network.

Signaling

An ATM connection procedure that implements explicit routes through switches to establish a communication link with another station on the network.

SONET

Synchronous Optical Network. A growing body of standards that defines all aspects of transmitting and managing digital traffic over optical (fiber) facilities.