Architecting Disaster Recovery for BYOC-Premise Edges using Multi-Cloud Trunking

How-To-Articles
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Architecting Disaster Recovery for BYOC-Premise Edges using Multi-Cloud Trunking

What This Guide Covers

You are designing a fully automated disaster recovery (DR) strategy for a Genesys Cloud BYOC Premise (Bring Your Own Carrier / Premise) deployment, where your physical Edges-hardware media gateways installed in your corporate data centers-are vulnerable to site-level failures (power outages, network partitions, physical hardware failures). When complete, your architecture will detect Edge failures within 30 seconds, automatically reroute all active SIP trunks and new inbound calls to a secondary cloud-based Edge cluster (BYOC Cloud or an alternate Premise site), and restore full WebRTC and SIP functionality for agents without manual intervention.

Prerequisites, Roles & Licensing

  • Genesys Cloud: Any CX tier with BYOC Premise enabled.
  • Permissions required:
    • Telephony > Trunk > Edit (for trunk rerouting)
    • Telephony > Edges > Edit (for Edge group management)
    • Telephony > Site > Edit (for site-level failover configuration)
  • Infrastructure:
    • At least two geographically separate Edge sites (or a hybrid Premise + Cloud edge config).
    • An external health-check monitoring service (AWS Route 53 health checks, Pingdom, or a custom Lambda poller).
    • A SIP carrier supporting dual-trunk failover or multiple SIP registration points.

The Implementation Deep-Dive

1. The BYOC Premise Single Point of Failure

In a BYOC Premise deployment, physical Edge appliances in your data center terminate SIP trunks from your carrier and handle WebRTC media for your agents. This creates three critical single points of failure:

  1. Site-Level Power Failure: If the data center loses power, all Edge appliances go offline.
  2. Network Partition: If the WAN link between your data center and Genesys Cloud degrades, Edges cannot receive call events.
  3. Edge Hardware Failure: Individual Edge appliances fail without redundancy.

Genesys Cloud natively provides Edge High Availability (HA) pairing for hardware failures (two Edges at the same site sharing state). However, site-level failures require an architectural DR strategy, not just hardware HA.

2. The Three-Layer DR Architecture

Layer 1 - Edge HA (Same-Site Redundancy)
Configure active/passive Edge pairing within each site. Edge 1 processes calls; Edge 2 is a hot standby. If Edge 1 fails, Edge 2 takes over within 30 seconds with no call drops for new calls (active calls are impacted).

Layer 2 - Site-to-Site BYOC Premise Failover
Configure two geographically separate Edge sites. Your SIP carrier has dual registration:

  • Primary: SIP trunk to edge-site-a.yourcompany.com
  • Secondary: SIP trunk to edge-site-b.yourcompany.com

The carrier uses SIP OPTIONS keepalive to detect when Site A’s Edges stop responding and automatically redirects inbound calls to Site B.

Layer 3 - Fallback to BYOC Cloud
If both Premise sites fail (a catastrophic scenario), calls failover to a pre-configured BYOC Cloud trunk (a Genesys-hosted cloud Edge). This is your last resort but ensures continuity.

3. Configuring Genesys Cloud Sites for Failover

Step 1: Create Two Sites

  1. Navigate to Admin > Telephony > Sites.
  2. Create Site_PrimaryDC (mapped to Edge Group A - your primary data center).
  3. Create Site_SecondaryDC (mapped to Edge Group B - your secondary data center).

Step 2: Configure the Primary Trunk with Failover
On your SIP trunk configuration (per carrier):

  1. Set the Primary SIP Registration URI to your Primary Edge’s outbound SIP IP.
  2. Set the Secondary SIP Registration URI to your Secondary Edge’s outbound SIP IP.
  3. Set SIP OPTIONS Interval to 30 seconds (carrier sends keepalive every 30 seconds; failure detected after 2 missed keepalives = 60-second RTO).

Step 3: Architect the Fallback Trunk
Create a second trunk of type BYOC Cloud as the tertiary carrier path. In your Architect call flow, add failover logic using the Transfer to External action, routing to the BYOC Cloud number if the primary trunk transfer fails.

4. Automated Failover via the Genesys Cloud API

Rather than waiting for the carrier’s SIP keepalive to detect failures, implement active health monitoring that can trigger Genesys-side trunk rerouting independently.

import requests
import time

GENESYS_API = "https://api.mypurecloud.com"
PRIMARY_TRUNK_ID = "trunk-id-primary"
BACKUP_TRUNK_ID = "trunk-id-cloud-byoc"
EDGE_HEALTH_URL = "https://edge-site-a.yourcompany.com/api/v2/status"

def monitor_and_failover(access_token: str):
    """
    Active health check loop. Triggers Genesys trunk failover if primary Edge is unreachable.
    Runs every 30 seconds on a Lambda scheduled trigger.
    """
    headers = {"Authorization": f"Bearer {access_token}"}
    
    # 1. Check Edge health
    try:
        health_resp = requests.get(EDGE_HEALTH_URL, timeout=5)
        if health_resp.status_code == 200:
            ensure_primary_trunk_active(headers)
            return  # All healthy
    except requests.exceptions.Timeout:
        print("Edge health check timed out - initiating failover assessment.")
    except requests.exceptions.ConnectionError:
        print("Edge unreachable - initiating failover.")
    
    # 2. Edge is unreachable - verify it's not a transient issue
    time.sleep(10)
    try:
        requests.get(EDGE_HEALTH_URL, timeout=5)
        print("Edge recovered on second check - no failover needed.")
        return
    except Exception:
        pass
    
    # 3. Confirmed failure - activate backup trunk and deactivate primary
    print("[FAILOVER] Primary Edge confirmed down. Activating BYOC Cloud trunk.")
    activate_trunk(BACKUP_TRUNK_ID, headers)
    
    # 4. Notify operations team via PagerDuty/Slack
    send_failover_alert(primary_trunk=PRIMARY_TRUNK_ID, backup_trunk=BACKUP_TRUNK_ID)

def activate_trunk(trunk_id: str, headers: dict):
    """Sets a trunk to Active state."""
    resp = requests.patch(
        f"{GENESYS_API}/api/v2/telephony/providers/edges/trunks/{trunk_id}",
        headers={**headers, "Content-Type": "application/json"},
        json={"state": "Active"}
    )
    resp.raise_for_status()

def ensure_primary_trunk_active(headers: dict):
    """Checks if the primary trunk is active; re-activates it if previously failed over."""
    resp = requests.get(
        f"{GENESYS_API}/api/v2/telephony/providers/edges/trunks/{PRIMARY_TRUNK_ID}",
        headers=headers
    )
    trunk = resp.json()
    
    if trunk.get("connectedStatus", {}).get("connected") is False:
        print("[RECOVERY] Primary Edge recovered. Failing back to primary trunk.")
        activate_trunk(PRIMARY_TRUNK_ID, headers)

5. Agent WebRTC Continuity During Failover

When Edges fail over, agents using WebRTC may experience a brief audio interruption on active calls. Calls in ACW or idle state are unaffected.

Minimizing Agent Impact:

  1. Configure Agents to use Cloud Media Edges (Genesys-hosted media servers) as their WebRTC endpoint rather than on-premise Edges. This decouples agent audio from the Premise Edge health entirely.
  2. For on-premise agents who must use local Edges for media, configure the Genesys Cloud Phone policy to allow the phone to re-register to the secondary Edge within 60 seconds.

Validation, Edge Cases & Troubleshooting

Edge Case 1: Failover Triggering During Planned Maintenance

If your network team schedules Edge maintenance at 2 AM and the health check Lambda triggers a failover because the Edge is deliberately offline, you waste a failover event and confuse the on-call team.
Solution: Implement a “Maintenance Mode” flag in DynamoDB. Your Lambda checks this flag before triggering any failover. Operations team sets the flag before planned maintenance and clears it afterward. The Lambda skips failover logic when the flag is set.

Edge Case 2: Split-Brain After Recovery

After the primary Edge recovers, both the primary and backup trunks may become active simultaneously (if the carrier automatically re-registers to the primary while your backup is still active). This causes call distribution to become unpredictable.
Solution: The ensure_primary_trunk_active function must explicitly deactivate the backup trunk when failing back, not just activate the primary. Implement this as a transactional operation: activate primary, confirm it’s healthy, then deactivate backup.

Edge Case 3: Active Call Audio Drop During Failover

SIP re-INVITE on an active call during trunk switchover causes a brief (100-500ms) audio interruption. For most customers this is acceptable; for traders or emergency services operators, it is not.
Solution: For ultra-high-availability requirements, implement a dedicated “hot-hot” carrier dual-path configuration where the carrier sends the SIP INVITE to both primary and secondary simultaneously, and your Edge infrastructure uses SIP early offer + answer to keep media flowing on both paths, switching instantaneously. This requires carrier support and is significantly more complex to implement.

Official References