This scenario is feasible for networks with any number of remote sites. A leased line generally provides a better reliability than a wireless cellular connection and its capacity is not limited by the GSM technology available at the center location. The leased line connects the SCADA center directly to the operator’s CORE WAN. Sometimes it can be substituted by an Internet connection between the SCADA center and the operator’s center.
The solution is the same as in Section 1.1, “Central M!DGE/MG102i – without VPN tunnels”. The only difference is that we do not have M!DGE/MG102i in the center.
The solution is the same as in Section 1.2, “Central M!DGE/MG102i – with VPN tunnels”. The only difference is that we do not have M!DGE/MG102i in the center, but there is a dedicated VPN concentrator which can handle more than 25 clients simultaneously (e.g. CISCO). The redundant VPN concentrator (cluster) may be used for higher reliability.
With a MG102i dual-SIM cellular router, we can use two SIM cards. If the primary provider network fails, the traffic is automatically switched to the second provider.
Even with a single provider, two independent Access Point Names (APN) can be used to improve overall reliability.
The fully redundant solution of the center is possible as follows:
Remote redundancy with two M!DGE/MG102i units with VRRP activated – this solution can handle both the network service failure and the M!DGE/MG102i router (+ antenna installation) HW fault:
A fully redundant solution for both the center and remote locations is certainly possible: