6.4 Scaling Dial-on-Demand Routing
6.4.1 Case study:  Scaling dial-on-demand routing
This case study describes the design of an access network that allows a large number of remote sites to communicate with an existing central-site network. The remote sites consist of local-area networks (LANs) that support several workstations. The workstations run transaction-processing software that accesses a database located at the central site. The following objectives guided the design of the access portion of the network:
  • The existing network could not be modified to accommodate access by the remote sites.
  • The central site must be able to connect to any remote site at any time, and any remote site must be able to connect to the central site at any time.
  • When choosing between alternative technologies, choose the most cost-effective technology.
  • The design must be flexible enough to accommodate additional remote sites in the future.