Aura Connect SBCaaS N+1 Resilience and Failover

How does N+1 work under normal operation?

Aura Connect N+1 does not operate as a traditional primary and standby configuration.

When both SBCs and connections are available, traffic is distributed across both using a round-robin mechanism. This means calls may be routed through either SBC during normal operation.

For example:

SBC 1 > Available
SBC 2 > Available

Traffic is distributed across both connections.

This approach allows both SBCs to actively handle traffic while also providing resilience should either connection become unavailable.

What happens if an SBC or connection fails?

If one SBC or connection becomes unavailable, Aura Connect will automatically route new traffic to the remaining available peer.

For example:

SBC 1 > Unavailable
SBC 2 > Available

New traffic will automatically use SBC 2.

No manual intervention is normally required.

SIP response considerations

Certain SIP responses are considered final because they indicate that the destination server is reachable and has actively responded.

These include:

• 401 - Unauthorized
• 403 - Forbidden
• 407 - Proxy Authentication Required
• Control trunk selection from their own SBC or PBX, where supported.
• Temporarily remove or disable the connection that should not receive traffic within the Aura Connect configuration.
• Raise a request with the Aura Service Desk where assistance is required to control the traffic path.
• Both SBCs can actively carry traffic during normal operation.
• Traffic is distributed using round-robin routing.
• If one connection becomes unavailable, traffic automatically uses the remaining peer.
• Recovered SBCs automatically return to service without a manual failback.
• Planned traffic switching can be managed by the customer or with assistance from Aura Support.
• Channel capacity is configured per SBC and should be sized appropriately if full capacity is required during a failure.

If one of these responses is received, Aura Connect will not automatically retry the call through the alternative SBC.

What happens when the failed SBC becomes available again?

There is no separate failback process.

Because both SBCs normally operate as active peers, once the unavailable SBC or connection becomes reachable again, it will automatically re-enter the round-robin routing pool.

For example:

SBC 1 > Available again
SBC 2 > Available

Traffic will once again be distributed across both connections.

No action is required from the customer or Aura.

Can traffic be manually directed to one SBC?

Yes. There are several options where planned maintenance, testing or another operational requirement means traffic needs to be directed through a specific connection.

Customers may:

For planned maintenance, we recommend coordinating any required changes with Aura Support in advance where possible.

How does channel capacity work with N+1?

Channel capacity is allocated per SBC/trunk.

For example, if a customer has:

When both SBCs are operational, the customer therefore has access to a combined 10 concurrent channels.

If one SBC becomes unavailable, calls will automatically route through the remaining SBC, but the maximum concurrent capacity will be limited to the channels configured on that SBC.

Capacity planning for full resilience

Customers should consider whether they require service resilience or service and capacity resilience.

For example, a configuration of two SBCs with five channels each provides 10 channels during normal operation, but only five channels during an individual SBC failure.

If the requirement is to maintain up to 10 concurrent calls even when one SBC is unavailable, each SBC should be provisioned with sufficient capacity to support the expected peak traffic independently.

Aura can help review expected concurrent call volumes and recommend an appropriate N+1 capacity configuration.

Summary

With Aura Connect SBCaaS N+1:

• Both SBCs can actively carry traffic during normal operation.
• Traffic is distributed using round-robin routing.
• If one connection becomes unavailable, traffic automatically uses the remaining peer.
• Recovered SBCs automatically return to service without a manual failback.
• Planned traffic switching can be managed by the customer or with assistance from Aura Support.
• Channel capacity is configured per SBC and should be sized appropriately if full capacity is required during a failure.

For assistance enabling N+1 resilience or reviewing an existing Aura Connect SBCaaS deployment, please contact the Aura Service Desk.