Designing a High-Availability BYOC Premise Architecture with AudioCodes Mediant VE

How-To-Articles
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Designing a High-Availability BYOC Premise Architecture with AudioCodes Mediant VE

What This Guide Covers

  • Architecting a redundant, cloud-native voice gateway solution using AudioCodes Mediant Virtual Edition (VE) for Genesys Cloud BYOC Premise.
  • Implementing Active-Active Edge Group logic and SBC high-availability (HA) pairs to ensure zero-downtime voice connectivity during regional outages or local hardware failures.
  • The end result is a resilient SIP signaling path that supports rapid failover and consistent media quality across distributed enterprise sites.

Prerequisites, Roles & Licensing

  • Licensing: Genesys Cloud CX (any tier) with BYOC Premise enabled.
  • Hardware/Virtualization: Two or more AudioCodes Mediant VE instances running on VMware ESXi, Hyper-V, or AWS/Azure.
  • Permissions: Telephony > Edge > View, Telephony > Trunk > Edit.
  • Connectivity: Redundant ISP links (preferably via BGP) to ensure the SBC remains reachable from the Genesys Cloud Media Tier.

The Implementation Deep-Dive

1. SBC High-Availability (HA) Pairing

The foundation of a resilient BYOC architecture is the SBC HA pair. AudioCodes Mediant VE uses a dedicated HA interface to sync configuration and call state (check-pointing) between the Primary and Secondary nodes.

The Trap:
Using a single virtual switch (vSwitch) for both the Management and HA interfaces. If the vSwitch or the underlying physical NIC fails, both nodes lose visibility of each other, potentially causing a “Split-Brain” scenario where both nodes attempt to become Active, leading to IP address conflicts and total voice failure.

Architectural Reasoning:
Always provision a dedicated, isolated virtual network for the HA link. This prevents network congestion from delaying the keep-alive heartbeats. Configure the Gratuitous ARP (GARP) settings on the SBC to ensure that when a failover occurs, the upstream router is immediately notified of the new MAC address associated with the Floating IP (VIP).

2. Genesys Cloud Edge Group Redundancy

A common mistake is treating the SBC as a single destination. To achieve true HA, the SBC must be integrated into a Genesys Cloud Edge Group.

The Trap:
Assigning the external SIP trunk to a single Edge. If that Edge goes offline for maintenance, the trunk is unreachable even if the SBC is healthy.

Solution:
Create an Edge Group and assign multiple Edges (or Media Tiers in BYOC Cloud) to it. Then, configure the External Trunk to use the Edge Group as its destination. This allows Genesys Cloud to distribute inbound calls across all healthy Edges, and provides outbound failover logic if one Edge loses connectivity to the SBC.

3. SIP Options Monitoring and Load Balancing

The SBC must actively monitor the health of the Genesys Cloud Media Tiers, and vice versa.

The Trap:
Relying solely on “ping” (ICMP) for health checks. A Media Tier might respond to a ping but have a crashed SIP stack.

Implementation:
Configure the AudioCodes SBC to send SIP OPTIONS heartbeats to the Genesys Cloud signaling IPs. Set the failure threshold to 3 missed heartbeats (approx. 60 seconds). Simultaneously, ensure the Genesys Cloud Trunk is configured with “Inbound SIP OPTIONS” enabled. This bi-directional monitoring ensures that if a specific path is degraded, the systems automatically reroute traffic to the secondary SBC node or the alternate Edge.

Validation, Edge Cases & Troubleshooting

Edge Case 1: Asymmetric Routing After Failover

  • The Failure Condition: Calls continue to work after failover, but one-way audio occurs because the firewall is still sending RTP to the old (inactive) SBC node.
  • The Root Cause: Long UDP timeout sessions on the corporate firewall.
  • The Solution: Configure the firewall to clear UDP sessions for the SBC VIP upon receiving a GARP packet, or reduce the UDP session timeout to < 30 seconds for the RTP port range.

Edge Case 2: Split-Brain Recovery

  • The Failure Condition: Both SBC nodes report as “Active” after a network flapping event.
  • The Root Cause: HA interface latency exceeded the keep-alive timer.
  • The Solution: Increase the HA heartbeat interval and implementation “Tie-Breaker” logic using a Ping Oracle (e.g., the default gateway). If a node cannot reach the Oracle and its partner, it should automatically transition to “Offline” or “Halt.”

Official References