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Diameter Protocol Integration

Diameter is the next-generation Authentication, Authorization, and Accounting (AAA) protocol, widely used in 4G/5G networks.

Overview

Diameter Protocol

Diameter provides:

  • Authentication and Authorization
  • Accounting and Charging
  • Policy Control
  • Mobility Management

Protocol Architecture

graph TD
    A[Applications] --> B[Base Protocol]
    B --> C[Transport Layer]
    C --> D[Network Layer]

Basic Configuration

const diameterConfig = {
  originHost: 'mme.example.com',
  originRealm: 'example.com',
  vendorId: 10415, // 3GPP
  productName: 'TelcoAPI-Client',
  firmwareRevision: 1
};

const client = await telcoapi.diameter.createClient(diameterConfig);

Applications

Authentication (S6a/S6d)

// Authentication Information Request (AIR)
const airRequest = {
  sessionId: 'mme.example.com;1234',
  authSessionState: 'NO_STATE_MAINTAINED',
  userName: '123450000000001', // IMSI
  visitedPlmnId: '123456',
  requestedEutranAuthInfo: {
    numberOfRequestedVectors: 1,
    immediateResponsePreferred: true
  }
};

const response = await client.s6a.sendAIR(airRequest);

Credit Control (Gy)

// Credit Control Request (Initial)
const ccrRequest = {
  sessionId: 'pgw.example.com;5678',
  authApplicationId: 4,
  requestType: 'INITIAL_REQUEST',
  subscriptionId: '123450000000001',
  serviceContextId: 'voice@3gpp.org'
};

const ccr = await client.gy.sendCCR(ccrRequest);

Message Format

AVP Structure

const avp = {
  code: 1,          // AVP Code
  flags: {
    vendor: true,   // Vendor-Specific
    mandatory: true // Mandatory AVP
  },
  vendorId: 10415,  // 3GPP
  value: 'example'  // AVP Value
};

Command Examples

Capability Exchange

const capabilityExchange = {
  command: 'Capabilities-Exchange',
  applicationIds: [
    { id: 16777251, vendor: 10415 }, // S6a
    { id: 4, vendor: 0 }             // Gy
  ],
  vendorSpecificIds: [10415]         // 3GPP
};

await client.diameter.exchangeCapabilities(capabilityExchange);

Error Handling

try {
  await client.s6a.sendULR(ulrRequest);
} catch (error) {
  switch (error.resultCode) {
    case 5001: // DIAMETER_AVP_UNSUPPORTED
      console.error('Unsupported AVP');
      break;
    case 5012: // DIAMETER_UNABLE_TO_COMPLY
      console.error('Unable to process request');
      break;
    default:
      console.error('Unknown error:', error);
  }
}

Security

TLS Configuration

const tlsConfig = {
  cert: fs.readFileSync('client-cert.pem'),
  key: fs.readFileSync('client-key.pem'),
  ca: fs.readFileSync('ca-cert.pem')
};

const secureClient = await telcoapi.diameter.createClient({
  ...diameterConfig,
  security: {
    tls: tlsConfig
  }
});

IPsec Setup

const ipsecConfig = {
  mode: 'tunnel',
  encryption: 'aes256',
  authentication: 'sha256',
  psk: 'your-pre-shared-key'
};

await client.diameter.configureIPsec(ipsecConfig);

Monitoring

Real-time Statistics

client.diameter.on('stats', (stats) => {
  console.log('Current TPS:', stats.transactionsPerSecond);
  console.log('Active Sessions:', stats.activeSessions);
  console.log('Average Response Time:', stats.avgResponseTime);
});

Logging

client.diameter.setLogLevel('debug');
client.diameter.on('log', (entry) => {
  console.log(`[${entry.level}] ${entry.message}`);
});

Best Practices

  1. Session Management 

    // Cleanup old sessions
await client.diameter.cleanupSessions({
  idleTimeout: 3600,
  maxAge: 86400
});

  2. Load Balancing 

    const peers = [
  { host: 'diameter1.example.com', port: 3868 },
  { host: 'diameter2.example.com', port: 3868 }
];

await client.diameter.configurePeers(peers);

  3. Failover Handling 

    client.diameter.on('failover', async (peer) => {
  console.log(`Failing over from ${peer.host}`);
  await client.diameter.reconnect();
});

Reference