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What is Frame Relay ?. : Frame Relay is a high-performance WAN protocal that operates at the physical and data link layers of the OSI reference model. : Frame Relay is an example of a packet-switching technology. -Variable-length packets
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What is Frame Relay ? : Frame Relay is a high-performance WAN protocal that operates at the physical and data link layers of the OSI reference model. : Frame Relay is an example of a packet-switching technology. -Variable-length packets -Statistical multiplexing
Frame Relay Standard : ITU-T Standard Frame Relay ANSI Standard Frame Relay -Cisco -Digital Equipment Corporation(DEC) -Northern Telecom -StrataCom
DCE Data Communication Equipment DTE A Data Terminal Equipment DTE B Data Terminal Equipment Concept of Data Communication
Architecture of Frame Relay Network Customer router At the customer premise Customer router At the customer premise Ethernet at The customer site Ethernet at The customer site
Architecture of Frame Relay Network(UNI) Frame Relay Network DSU DSU V.35 Interface Customer router At the customer premise
Architecture of Frame Relay Network(NNI) UNI Network UNI Network NNI Connection
Frame Relay Connections 1. Switched Virtual Circuits (SVC) are temporaly connections used is situations requiring only sporadic data transfer between DTE devices across the Frame Relay network. 2. Permanent Virtual Circuits (PVC) are permanently established connections that are used for frequent and consistent data transfers between DTE devices across the Frame Relay network.
Data-Link Connection Identifier • Frame Relay virtual circuits are identified by data-link connection identifiers (DLCI). • Dlci = 0 and 1023 are Signaling Control by Network cannot used by User define. • Dlci 0 : for Annex-D. • Dlci 1023 : for Annex-A and Cisco forum.
Congestion-Control Mechanisms • Forward-Explicit congestion notification (FECN) . • Backward-Explicit congestion notification (BECN) .
FECN BECN Data Transfer Congestion-Control Mechanisms
Local Management Control(LMI) How do we know the connection still active ? Yes, we know by used LMI monitor. LMI Type : • Annex-D • Annex-A • Cisco
Benefit of Frame Relay Service • Point to Multipoint instead Point to Point • Flexible for networking grow up