Frame relay can be very cost competitive when compared to the dedicated types of DDS circuit. However, experience in NZ has shown that the overall throughput of a frame relay link does not come up to the performance of a DDS circuit even though an CIR has been purchased. There would appear to be times when the FR Network is either overloaded generally or at specific points. Within the major cities in New Zealand there are lower cost options for Internet connections. The 9k6 and lower speeds are really not suitable for an Internet connection as they are simply too low throughput.
Lower cost is a relative term but lower it is when compared to standard DDS charges.
A variation on standard dial up is Centrex ISDN . This really is a low cost option if connecting to an ISP in the same CBD since there will be no per-minute charges for using ISDN if part of the ISP's Basic Business Group. Probably the biggest problem with Centrex ISDN is actually finding an ISP to connect to who provides this service. A second issue for ISPs is that Telecom NZ appear to have problems in providing PRI circuits and in provisioning them reliably. It appears that the NEC neax61e PRI switching equipment is a major source of headaches for Telecom and interfacing to certain manufacturer's PRI routers and modem servers has been less than enjoyable for all parties involved.