Also, QoS, Security and Scalability are all key issues to successful implementation. Cisco products that suit the need of central site include Cisco 3600 series, Cisco 4000 series, Cisco AS5x00 series and Cisco 7000 series Remote site allows remote users to connect to the company site. Pay attention to authentication and availability. Cisco products that suit the need of remote offices include Cisco 1600 series, Cisco 1700 series, Cisco 2500 series and Cisco 2600 series You are strongly recommended the read the product documentation for the above mentioned Cisco products. Telecommuter site tends to have few number of users and need only dialup services.
Flexibility is the key, as mobile users tend to move around all the time.
Typical router interfaces for remote access include Asynchronous serial, Synchronous serial, BRI, Channelized T1 or E1. Use Cisco Product Selection tool to plan for the hardware requirement. You need PRI interface for ISDN PRI as well as asynchronous calls. You need dial up modem for asynchronous calls. You need serial interface for Frame Relay.