When operating in IP Site Connect Mode, MOTOTRBO combines the logical channels of multiple MOTOTRBO systems (operating in digital repeater mode at dispersed locations) into one logical channel covering all locations. In this mode, repeaters across dispersed locations exchange voice and data packets over an IPv4-based back-end network.
When a new call starts at one of the logical channel of a repeater, the repeater sends the call to all the repeaters and all these repeaters repeat the call on their corresponding logical channel. This allows a radio in the coverage area of any repeater to participate in the call. Thus, the coverage area of an IP Site Connect system is the sum of the coverage areas of all the repeaters. However, note that an IP Site Connect configuration does not increase the capacity (i.e. number of calls per hour) of the system. The capacity of one Wide Area Channel of an IP Site Connect system is approximately the same as that of a single repeater working in digital repeater mode.
In an IP Site Connect configuration, MOTOTRBO radios support all the features that they already support in digital repeater mode. Additionally, the radios are capable of automatically roaming from one site to another.
The IP Site Connect configuration of MOTOTRBO does not require any new hardware besides backend network devices such as routers. If a customer has multiple MOTOTRBO systems working in digital repeater mode at dispersed sites and wants to convert them into an IP Site Connect system then the repeaters and the radios should be updated with new software and the repeaters need to be connected to an IPv4-based backend network.
MOTOTRBO has three security features in the IP Site Connect configuration.
Þ Provides the confidentiality of voice and data payloads by extending the privacy feature, whether Basic or Enhanced, to cover the communication over the backend network.
Þ Ensures that all the messages between repeaters are authentic.
Þ Supports Secure VPN (Virtual Private Network) based communication between the repeaters for customers needing higher level of security (protection against replay attack).
The backend network can be a dedicated network or most probably an internet provided by an Internet Service Provider (ISP). ISPs provide a range of technologies such as dial-up, DSL (typically, ADSL), cable modem, broadband wireless access, ISDN, Frame Relay, Satellite Internet access, etc. The backend network cannot be based on a dial-up connection (due to small bandwidth) or Satellite Internet access (due to large delay).