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Ring2All Documentation

Ring2All SBC - Dispatcher & Load Balancing Module Documentation

4 min readUpdated: Sep 26, 2026
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Table of Contents

Section titled “Table of Contents”
  1. Module Overview (Technical)
  2. Module Overview (Commercial/Business)
  3. Module Overview (End User/Administrator)
  4. Configuration Sections
  5. Settings Reference
  6. Common Scenarios & Examples
  7. Limitations & Important Notes
  8. Troubleshooting Tips
  9. Glossary

1. Module Overview (Technical)

Section titled “1. Module Overview (Technical)”

What Is the Dispatcher Module?

Section titled “What Is the Dispatcher Module?”

The Dispatcher Module in Ring2All SBC manages high-availability Session Border Controller traffic distribution, round-robin load balancing, weight-based routing, and automated failover monitoring across groups of Telephony Server media nodes, PSTN gateways, and carrier SBCs.

Powered by Kamailio’s dispatcher module, Ring2All SBC sends active SIP OPTIONS keepalive pings at regular intervals to verify gateway health. If a node fails to respond or returns server errors (e.g. 500, 503), the Dispatcher instantly marks it as inactive (IP_INACTIVE) and re-routes pending traffic to healthy nodes.

Architecture

Section titled “Architecture”
┌─────────────────────────────────────────────────────────────────┐
│           Ring2All SBC - Dispatcher Architecture                 │
├─────────────────────────────────────────────────────────────────┤
│                                                                 │
│  Inbound SIP Traffic ──> Kamailio SBC Core (Dispatcher)         │
│                                │                                │
│                     ┌──────────┼──────────┐                     │
│                     │ (Options Keepalive) │                     │
│                     ▼          ▼          ▼                     │
│                ┌────────┐ ┌────────┐ ┌────────┐                 │
│                │ Node 1 │ │ Node 2 │ │ Node 3 │                 │
│                │ (Active) │ (Active) │ (Failed)                 │
│                └────────┘ └────────┘ └────────┘                 │
│                     │          │          X (Skipped)           │
│                     └──────────┴──────────┘                     │
│                                │                                │
│                                ▼                                │
│                     Telephony Server / Carrier Pool                   │
│                                                                 │
└─────────────────────────────────────────────────────────────────┘

2. Module Overview (Commercial/Business)

Section titled “2. Module Overview (Commercial/Business)”

Business Benefits

Section titled “Business Benefits”
  1. Zero-Downtime Telephony Operations: Automatically detects gateway failures in under 2 seconds, preventing dropped calls and agent downtime.
  2. Optimal Capacity Utilization: Distributes traffic evenly across media servers according to processing capacity (weight algorithms).
  3. Carrier Cost Optimization: Route traffic dynamically based on dispatcher group rules and carrier priorities.

3. Module Overview (End User/Administrator)

Section titled “3. Module Overview (End User/Administrator)”

What Can You Do in This Module?

Section titled “What Can You Do in This Module?”
  • Define Dispatcher Groups: Create logical pools for Telephony nodes, PSTN Trunks, or Outbound Carriers.
  • Configure Load Balancing Algorithms: Choose between Hash-based (Call-ID, From-URI), Round-Robin, or Weight-based distribution.
  • Set Probing Parameters: Define SIP OPTIONS ping intervals, timeout limits, and failure thresholds.
  • View Gateway Health Status: Real-time status monitoring (Active, Inactive, Probing, Disabled).

4. Configuration Sections

Section titled “4. Configuration Sections”

1. Dispatcher Rules Grid

Section titled “1. Dispatcher Rules Grid”

Lists all registered gateways with group IDs, destination URIs, weights, priority, and real-time status.

2. Gateway Properties Form

Section titled “2. Gateway Properties Form”

Allows adding or editing destination URIs (sip:192.168.10.32:5060), flags, socket bindings, and description.

5. Settings Reference

Section titled “5. Settings Reference”
Field Name Type Options / Format Description
setid Integer Positive integer (e.g. 10) Dispatcher Group ID.
destination Input sip:host:port SIP URI of target gateway or media server.
flags Integer Bitmask (e.g. 8 = Probing) Operational flags for Kamailio dispatcher.
priority Integer 0-100 Routing priority order within dispatcher set.

6. Common Scenarios & Examples

Section titled “6. Common Scenarios & Examples”

Scenario: Configuring High-Availability Telephony Cluster

Section titled “Scenario: Configuring High-Availability Telephony Cluster”
  1. Create Dispatcher Set 1 for Telephony Server Media Pool.
  2. Add Node A: sip:192.168.10.30:5060, Priority 10, Flags 8.
  3. Add Node B: sip:192.168.10.31:5060, Priority 10, Flags 8.
  4. Kamailio pings both nodes every 5 seconds. If Node A goes down, all traffic seamlessly flows to Node B.

7. Limitations & Important Notes

Section titled “7. Limitations & Important Notes”
  • Ensure ds_ping_interval is set between 2s and 10s to avoid unnecessary network overhead while maintaining rapid failover.

8. Troubleshooting Tips

Section titled “8. Troubleshooting Tips”
Symptom Probable Cause Solution
Node marked INACTIVE Firewall blocking SIP OPTIONS Verify port 5060 UDP is allowed between Kamailio and media nodes.
Dispatcher rules not reloading Memory cache not synced Run kamcmd dispatcher.reload via SBC CLI or API.

9. Glossary

Section titled “9. Glossary”
  • Dispatcher Set: Logical grouping of destinations sharing the same routing policy.
  • Probing: Periodic transmission of SIP OPTIONS pings to verify destination health.