What are the failover capabilities of the G200 router?
- Datto G200 router
The G200 router supports basic local link loss based WAN redundancy. This functionality has several limitations however, so please review the following points before attempting to use both WAN ports on a single G200 in any network design plans.
Only one physical WAN interface (Copper or SFP) can be active
The G200 router has two physical WAN ports, however, these two physical ports connect to a single internal interface. This means that only one of two WAN ports can be active at any given time. The second or "inactive" WAN interface will show no Ethernet link at all since the physical port will be disconnected from the internal interface. This also means that load balancing behaviors or other active/active use cases are not possible on the G200.
WAN link redundancy/failover is based on local link loss
The router does not support any failover condition other than local link loss. This means that the router will never try to switch from one WAN port to another unless the Ethernet link state on the currently active WAN port goes down. There are no IP connectivity checks done. Local link loss generally only occurs in one of three scenarios: physical cable disconnection, power loss, or manual port shutdown. Most modems on the market do not shutdown their LAN port when they lose sync.
Only one WAN IP configuration state is allowed
Since there is only one internal WAN interface, there can only be one IP address assignment. This means that the WAN IP configuration will not change even if the physical WAN interface in use changes. If both physical WAN ports are connected to sources that provide DHCP leases, then a WAN configuration of "DHCP" will work. However, if either WAN connection uses static IPs, then the same static IP configuration needs to work on both WAN connections or else the router will simply go offline when a failover occurs.
Known issue with copper SFP modules preventing failover
There is a known issue that is currently preventing the router from detecting a link loss event on copper SFP modules. This means that if you are actively using a copper SFP module, the router will never failover to the built-in copper WAN port since the failover condition (local link loss) is not detectable from the copper SFP module. We are investigating the issue and hope to resolve this in the future, but at this time we do not recommend using any copper SFTP modules with the G200.