Legacy Open Mesh: What are the failover capabilities of the G200 router?

Question

What are the failover capabilities of the G200 router?

Environment

  • Datto G200 router

Answer

The G200 router supports basic local link loss based WAN redundancy. To understand this function's limitations, 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 connecting to a single internal interface.

  • Only one of two WAN ports can be active at a time.
  • The second or "inactive" WAN interface will show no Ethernet link since the physical port is disconnected from the internal interface.
  • Load-balancing behaviors or other active/active use cases are not possible on the G200.

The router bases WAN link redundancy/failover on local link loss

The router does not support any failover condition other than local link loss.

  • 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.
  • The router does not perform IP connectivity checks.
  • Local link loss generally occurs in one of three scenarios: physical cable disconnection, power loss, or manual port shutdown.
  • Most commercially available modems do not shut down 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.

  • 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.
  • If either WAN connection uses static IPs, then the same static IP configuration must work on both WAN connections, or else the router will go offline when a failover occurs.

A known issue with copper SFP modules prevents failover

There is a known issue that is currently preventing the router from detecting a link loss event on copper SFP modules.

  • If you are actively using a copper SFP module, the router will never failover to the built-in copper WAN port, since the copper SFP module cannot detect the failover condition (local link loss).
  • We are investigating the issue and hope to resolve this in the future, but at this time, we do not recommend using any copper SFP modules with the G200.