Chapter 18 Virtual-Circuit Networks: Frame Relay and ATM Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
18-1  FRAME RELAY Frame Relay is a virtual-circuit wide-area network that was designed in response to demands for a new type of WAN in the late 1980s and early 1990s. Architecture Frame Relay Layers Extended Address FRADs VOFR LMI Topics discussed in this section:
Figure 18.1  Frame Relay network
VCIs in Frame Relay are called DLCIs. Note
Figure 18.2  Frame Relay layers
Frame Relay operates only at the physical and data link layers. Note
Figure 18.3  Frame Relay frame
Frame Relay does not provide flow or error control; they must be provided by the upper-layer protocols. Note
Figure 18.4  Three address formats
Figure 18.5  FRAD
18-2  ATM Asynchronous Transfer Mode (ATM) is the  cell relay  protocol designed by the ATM Forum and adopted by the ITU-T.  Design Goals Problems Architecture Switching ATM Layers Topics discussed in this section:
Figure 18.6  Multiplexing using different frame sizes
A cell network uses the cell as the basic unit of data exchange. A cell is defined as a small, fixed-size block of information. Note
Figure 18.7  Multiplexing using cells
Figure 18.8  ATM multiplexing
Figure 18.9  Architecture of an ATM network
Figure 18.10  TP, VPs, and VCs
Figure 18.11  Example of VPs and VCs
Note that a virtual connection is defined by a pair of numbers:  the VPI and the VCI. Note
Figure 18.12  Connection identifiers
Figure 18.13  Virtual connection identifiers in UNIs and NNIs
Figure 18.14  An ATM cell
Figure 18.15  Routing with a switch
Figure 18.16  ATM layers
Figure 18.17  ATM layers in endpoint devices and switches
Figure 18.18  ATM layer
Figure 18.19  ATM headers
Figure 18.20  AAL1
Figure 18.21  AAL2
Figure 18.22  AAL3/4
Figure 18.23  AAL5
18-3  ATM LANs ATM is mainly a wide-area network (WAN ATM); however, the technology can be adapted to local-area networks (ATM LANs). The high data rate of the technology has attracted the attention of designers who are looking for greater and greater speeds in LANs.  ATM LAN Architecture LAN Emulation (LANE) Client/Server Model Mixed Architecture with Client/Server Topics discussed in this section:
Figure 18.24  ATM LANs
Figure 18.25  Pure ATM LAN
Figure 18.26  Legacy ATM LAN
Figure 18.27  Mixed architecture ATM LAN
Figure 18.28  Client and servers in a LANE
Figure 18.29  Client and servers in a LANE

Ch18

  • 1.
    Chapter 18 Virtual-CircuitNetworks: Frame Relay and ATM Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
  • 2.
    18-1 FRAMERELAY Frame Relay is a virtual-circuit wide-area network that was designed in response to demands for a new type of WAN in the late 1980s and early 1990s. Architecture Frame Relay Layers Extended Address FRADs VOFR LMI Topics discussed in this section:
  • 3.
    Figure 18.1 Frame Relay network
  • 4.
    VCIs in FrameRelay are called DLCIs. Note
  • 5.
    Figure 18.2 Frame Relay layers
  • 6.
    Frame Relay operatesonly at the physical and data link layers. Note
  • 7.
    Figure 18.3 Frame Relay frame
  • 8.
    Frame Relay doesnot provide flow or error control; they must be provided by the upper-layer protocols. Note
  • 9.
    Figure 18.4 Three address formats
  • 10.
  • 11.
    18-2 ATMAsynchronous Transfer Mode (ATM) is the cell relay protocol designed by the ATM Forum and adopted by the ITU-T. Design Goals Problems Architecture Switching ATM Layers Topics discussed in this section:
  • 12.
    Figure 18.6 Multiplexing using different frame sizes
  • 13.
    A cell networkuses the cell as the basic unit of data exchange. A cell is defined as a small, fixed-size block of information. Note
  • 14.
    Figure 18.7 Multiplexing using cells
  • 15.
    Figure 18.8 ATM multiplexing
  • 16.
    Figure 18.9 Architecture of an ATM network
  • 17.
    Figure 18.10 TP, VPs, and VCs
  • 18.
    Figure 18.11 Example of VPs and VCs
  • 19.
    Note that avirtual connection is defined by a pair of numbers: the VPI and the VCI. Note
  • 20.
    Figure 18.12 Connection identifiers
  • 21.
    Figure 18.13 Virtual connection identifiers in UNIs and NNIs
  • 22.
    Figure 18.14 An ATM cell
  • 23.
    Figure 18.15 Routing with a switch
  • 24.
    Figure 18.16 ATM layers
  • 25.
    Figure 18.17 ATM layers in endpoint devices and switches
  • 26.
    Figure 18.18 ATM layer
  • 27.
    Figure 18.19 ATM headers
  • 28.
  • 29.
  • 30.
  • 31.
  • 32.
    18-3 ATMLANs ATM is mainly a wide-area network (WAN ATM); however, the technology can be adapted to local-area networks (ATM LANs). The high data rate of the technology has attracted the attention of designers who are looking for greater and greater speeds in LANs. ATM LAN Architecture LAN Emulation (LANE) Client/Server Model Mixed Architecture with Client/Server Topics discussed in this section:
  • 33.
    Figure 18.24 ATM LANs
  • 34.
    Figure 18.25 Pure ATM LAN
  • 35.
    Figure 18.26 Legacy ATM LAN
  • 36.
    Figure 18.27 Mixed architecture ATM LAN
  • 37.
    Figure 18.28 Client and servers in a LANE
  • 38.
    Figure 18.29 Client and servers in a LANE