1 - Implementing high availability

1-1-comatis
  • Monitoring and automatic selection of routes
  • Automatic monitoring of the status of modems and equipment
  • Using standard protocol

2 - Routing example for ModBus applications

comatis2-2
  • IP encapsulation of the serial protocol
  • IP routing based on the serial address

3 - Example of a fully redundant network

Redundant master modem (“Ethernet redundancy”) to one or more redundant “station” modems

comatis3-2

Master modems and redundant stations modems:

  • VRRP (i.e. Virtual Router Redundancy Protocol) : if the active modem fails, the standby modem becomes active.
  • By default, the traffic between DTE-A and DTE-B passes through the M1 and M3 modems.
  • If M1 becomes inaccessible: the traffic between DTE-A and DTE-B goes through the M2 and M3 modems.
  • If M3 becomes inaccessible: the traffic between DTE-A and DTE-B goes through M2 and M4 modems.
  • If M1 becomes accessible again: the traffic between DTE-A and DTE-B passes through modems M1 and M4.