Chapter 18 Frame Relay

Frame Relay Frame Relay is a virtual-circuit technology that provides low-level(physical and data link layer) service in response to following demands. Higher data rate at lowest cost Bursty Data Less overhead due to improved Transmission Media

Frame Relay versus Pure Figure 18-1 Frame Relay versus Pure Mesh T-Line Network

Fixed-Rate versus Bursty Data Figure 18-2 Fixed-Rate versus Bursty Data

Figure 18-3 X.25 Traffic

Advantages Frame Relay operates at higher speed. It allows bursty data. It allows frame size of 9000 byte. Frame relay is less expensive than other traditional WAN.

Disadvantage Some time it doesnot support for high data rate. Frame relay allows variable-length frames. This may delays for different users. Frame relay is not suitable for sending delay sensitive data such as real-time voice or video. Eg Teleconferencing.

Figure 18-5 Frame Relay Network

Figure 18-6 DLCIs

Types of connection in Frame Relay Permanent Virtual Circuit (PVC) Switch Virtual Circuit (SVC)

Permanent Virtual Circuit (PVC ) Figure 18-7 Permanent Virtual Circuit (PVC )

Figure 18-8 SVC Setup and Release

Figure 18-9 SVC DLCIs

Figure 18-10 DLCIs Inside a Network

Figure 18-11 Frame Relay Switch

Figure 18-12 Frame Relay Layers

Comparing Layers in Frame Relay and X.25 Figure 18-13 Comparing Layers in Frame Relay and X.25

Figure 18-14 Frame Relay Frame

Figure 18-15 BECN

Figure 18-16 FECN

Four Cases of Congestion Figure 18-17 Four Cases of Congestion

Figure 18-18 Leaky Bucket

A Switch Controlling the Output Rate Figure 18-19 A Switch Controlling the Output Rate

Flowchart for Leaky Bucket Algorithm Figure 18-20 Flowchart for Leaky Bucket Algorithm

End……

Example of Leaky Bucket Algorithm Figure 18-21 Example of Leaky Bucket Algorithm

Relationship between Traffic Figure 18-22 Relationship between Traffic Control Attributes

User Rate in Relation to Bc and Bc + Be Figure 18-23 User Rate in Relation to Bc and Bc + Be

Figure 18-24 Three Address Formats

Figure 18-25 FRAD