TwinCast Recovery¶

The TwinCast Recovery module provides automatic failover functionality for multicast streaming with zero downtime. It ensures maximum reliability for content delivery by automatically switching between primary and backup servers without interrupting the broadcast.

Overview¶

TwinCast Recovery is designed for content providers who need to deliver multicast streams with maximum reliability. The module implements a sophisticated standby mechanism that monitors the primary server and automatically activates the backup server when needed.

Key Features¶

Zero Downtime Failover: Automatic switching without broadcast interruption
Standby Mode: Backup servers monitor primary server status
IGMP Compatibility: Works with any IGMP receiver
Automatic Recovery: Seamless return to primary server when available
Real-time Monitoring: Continuous status monitoring via stats.push[0].standby_status

How Standby Mode Works¶

The standby mode operates through a sophisticated monitoring and switching mechanism:

Primary Server Operation¶

Active Broadcasting: Primary server sends streams to multicast group address
Continuous Monitoring: Backup server constantly monitors multicast group activity
Status Verification: Backup server checks if any server is sending multicast packets

Backup Server Operation¶

Standby State: Backup server remains in standby mode while primary is active
Automatic Activation: When primary server goes offline, backup starts streaming
Automatic Deactivation: When primary returns, backup stops and returns to standby

Failover Process¶

Detection: Backup server detects absence of multicast packets from primary
Activation: Backup server immediately starts streaming to multicast group
Recovery: When primary server returns, backup automatically stops and returns to standby
Monitoring: Continuous monitoring ensures immediate response to any issues

Configuration¶

Basic Setup¶

Configure TwinCast Recovery through the Mcaster Admin UI:

Access Stream Settings: Go to the Output tab of stream settings
Configure Primary Server: In the URL column of Push live video to certain URLs section, specify: udp://239.1.1.1:1234 Where:
239.1.1.1 - multicast group address
1234 - port for Mcaster to listen to
Add Backup Server: Configure backup server with same multicast group settings
Enable Standby Mode: Open Options and enable standby mode by checking Standby box
Apply Changes: Click Save to activate configuration

Advanced Configuration¶

Multicast Group Settings¶

stream primary_stream {
  input udp://239.0.0.1:1234;
  push udp://239.1.1.1:1234;
}

stream backup_stream {
  input udp://239.0.0.1:1234;
  push udp://239.1.1.1:1234 standby;
}

Network Considerations¶

Multicast Routing: Ensure proper multicast routing configuration
IGMP Snooping: Configure switches for optimal multicast delivery
Bandwidth Planning: Account for both primary and backup streams
Network Isolation: Consider VLAN configuration for multicast traffic

Monitoring and Status¶

Standby Status Monitoring¶

Monitor the standby status using the stats.push[0].standby_status field:

{
  "stats": {
    "push": [
      {
        "standby_status": "active|waiting"
      }
    ]
  }
}

Status Values¶

active: Server is currently broadcasting to multicast group
waiting: Server is monitoring but not broadcasting (standby mode)

Monitoring Best Practices¶

Regular Status Checks: Monitor standby_status field regularly
Log Analysis: Review logs for failover events
Performance Metrics: Track switching times and reliability
Alert Configuration: Set up alerts for status changes

Use Cases¶

Content Provider Redundancy¶

Satellite Broadcasting: Ensure continuous satellite feed delivery
Cable Networks: Maintain service during server maintenance
Live Events: Prevent broadcast interruption during critical events
24/7 Operations: Maintain service availability around the clock

Enterprise Applications¶

Corporate Broadcasting: Reliable internal video distribution
Educational Institutions: Uninterrupted lecture streaming
Government Communications: Reliable emergency broadcast systems

Troubleshooting¶

Common Issues¶

Backup Server Not Activating¶

Check Network Connectivity: Verify multicast routing
Verify Standby Configuration: Ensure standby mode is enabled
Monitor Logs: Check for error messages in system logs
Test Multicast Group: Verify multicast group accessibility

Primary Server Not Detected¶

Network Configuration: Check multicast group settings
Firewall Rules: Ensure multicast traffic is allowed
IGMP Configuration: Verify IGMP snooping on switches
Server Status: Confirm primary server is broadcasting

Frequent Failovers¶

Network Stability: Check for network instability
Server Performance: Monitor primary server resources
Multicast Congestion: Check for multicast traffic issues
Configuration Conflicts: Verify no conflicting multicast groups

Diagnostic Commands¶

# Check multicast group status
netstat -g

# Monitor multicast traffic
tcpdump -i eth0 udp port 1234

# Verify IGMP membership
cat /proc/net/igmp

Performance Optimization¶

Switching Speed Optimization¶

Network Latency: Minimize network latency between servers
Detection Time: Optimize multicast packet detection timing
Buffer Configuration: Adjust buffer sizes for optimal performance
CPU Resources: Ensure adequate CPU resources for monitoring

Resource Management¶

Memory Usage: Monitor memory consumption during failover
CPU Utilization: Track CPU usage during standby monitoring
Network Bandwidth: Plan for multicast traffic requirements
Storage I/O: Consider storage requirements for logging

Security Considerations¶

Network Security¶

Multicast Authentication: Implement multicast authentication if required
Network Isolation: Use VLANs to isolate multicast traffic
Access Control: Restrict access to multicast configuration
Monitoring: Monitor for unauthorized multicast traffic

Configuration Security¶

Secure Configuration: Protect configuration files
Access Logging: Log all configuration changes
Backup Security: Secure backup of configuration files
Update Procedures: Follow secure update procedures