The Partner SD-WAN Gateway provides resiliency by detecting failures and failing over to an alternate Partner SD-WAN Gateway. This includes the ability of a Partner SD-WAN Gateway to detect failure conditions and for the surrounding infrastructure to detect failures of the SD-WAN Gateway itself.
Consider the following SD-WAN Gateway topology:
This figure shows three distinct failure zones:
The following figure shows a typical failure scenario that occurs between the
SD-WAN Gateway and Provider Edge router and describes the activity that occurs.
| Failure Zone | Component | Description |
|---|---|---|
| 1 | Provider Edge | The Provider Edge is one instance in which failure can be detected either from the Provider Edge router pinging the SD-WAN Gateway, or from the SD-WAN Gateway to the Provider Edge router. |
| 2 | Call Controller | The SD-WAN Gateway should be able to ping the Provider Edge router or Call Controller to verify connectivity. |
| 3 | WAN | The SD-WAN Gateway should have a stateful ping responder that responds only if the WAN zone is available. |
The Partner SD-WAN Gateway also supports configurable route costs to allow for more flexible failure scenarios. Finally, there is an additional hand-off type required where neither NAT nor VLAN tags are applied to the packets and they are simply passed through to the Provider Edge router.
