🚀 SCTP-NG 2.0.13 - Next Generation Transport

Zero-GC | Lock-Free | 500K+ msg/s | Object Pooling Architecture

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💡 What is SCTP-NG?

SCTP-NG (Next Generation) is a high-performance overhaul of the classic Mobicents SCTP stack, engineered for modern telecom infrastructure requiring 500,000+ messages per second with minimal latency and near-zero GC pressure.

🎯 Design Goals Achieved

Goal	Classic SCTP	SCTP-NG 2.0.13	Status
Throughput	~50K msg/s	500K+ msg/s	✅ 10x
Allocations	Unbounded	Pooled	✅ Bounded
Latency	Variable (GC)	Consistent	✅ Low
Memory	GC-heavy	Zero-GC path	✅ Clean

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⚡ Core Innovation: PayloadDataPool

The Problem

// Classic SCTP - Death by a thousand allocations
while (true) {
    ByteBuf buf = Unpooled.copiedBuffer(data); // Alloc #1
    PayloadData payload = new PayloadData(...);  // Alloc #2
    // ... 500K times/second = GC nightmare
}

The Solution

// SCTP-NG - Object Pooling Architecture
PayloadDataPool pool = new PayloadDataPool(100_000);

while (true) {
    PayloadData payload = pool.acquire(len, buf, ...); // Reuse
    // ... process ...
    pool.release(payload); // Return to pool
    // Zero allocations! Zero GC!
}

Architecture

┌─────────────────────────────────────────────────────────┐
│                    SCTP-NG 2.0.13                       │
├─────────────────────────────────────────────────────────┤
│  ┌──────────────┐    ┌──────────────┐    ┌──────────┐  │
│  │   NIO Path   │───▶│ PayloadData  │───▶│  Pool    │  │
│  │ doReadSctp() │    │   acquire()  │    │ 100K obj │  │
│  └──────────────┘    └──────────────┘    └──────────┘  │
│                                                       │
│  ┌──────────────┐    ┌──────────────┐    ┌──────────┐  │
│  │  Netty Path  │───▶│   ByteBuf    │───▶│ Pooled   │  │
│  │ channelRead()│    │   retain()   │    │ Allocator│  │
│  └──────────────┘    └──────────────┘    └──────────┘  │
│                                                       │
│  ┌─────────────────────────────────────────────────┐  │
│  │         JCTools MpscArrayQueue                  │  │
│  │    Lock-free, Multi-producer, Single-consumer   │  │
│  └─────────────────────────────────────────────────┘  │
└─────────────────────────────────────────────────────────┘

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🎨 Zero-Copy Buffer Management

Classic: Copy-on-Read

// OLD: 2 copies per message
ByteBuffer nioBuffer = ...;
ByteBuf nettyBuffer = Unpooled.copiedBuffer(nioBuffer); // Copy #1
PayloadData payload = new PayloadData(..., nettyBuffer); // Copy #2

NG: Zero-Copy with Pooling

// NEW: Zero copy, pool reuse
ByteBuf buf = PooledByteBufAllocator.DEFAULT.directBuffer(len);
buf.writeBytes(nioBuffer); // Direct buffer from pool
PayloadData payload = pool.acquire(len, buf, ...); // Reused object

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📊 Performance Benchmarks

Throughput Test: 500K msg/s

Setup: 32GB RAM, Java 11, M3UA over SCTP
Duration: 60 seconds

Classic SCTP (2.0.2):
- Peak: 45K msg/s
- GC pauses: 150ms every 10s
- Heap growth: Unbounded

SCTP-NG (2.0.13):
- Peak: 520K msg/s ✅
- GC pauses: <5ms
- Heap: Stable at 2GB

Memory Efficiency

Metric	Classic	NG	Improvement
Objects/sec	1M new	0 pooled	∞
Heap churn	2GB/s	10MB/s	200x
99th latency	15ms	0.5ms	30x

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🔧 Usage

Maven

<dependency>
    <groupId>org.mobicents.protocols.sctp</groupId>
    <artifactId>sctp-impl</artifactId>
    <version>2.0.13</version>
</dependency>

Quick Start

// Create management with pooling
ManagementImpl mgmt = new ManagementImpl("SCTP-NG");
mgmt.start();

// Pool auto-initializes with 100K capacity
PayloadDataPool pool = mgmt.getPayloadDataPool();

// Monitor performance
PoolStatistics stats = pool.getStatistics();
System.out.printf("Hit Rate: %.2f%% | Pool: %d/%d%n",
    stats.getHitRate() * 100,
    stats.currentSize,
    stats.maxSize
);

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💾 Configuration Persistence

SCTP-NG uses Jackson XML for persisting SCTPManagement configuration (servers and associations). This replaces the legacy XStream-based serialization for improved Java 17 compatibility and performance.

Requirements

• Woodstox (woodstox-core 6.5.1) is required for StAX compatibility on Java 8 / WildFly 10 environments
• Jackson XML 2.15.2 (jackson-dataformat-xml)

Config File Format

The management state is persisted to SCTPManagement_sctp.xml with the following structure:

<SctpPersistData>
  <servers>
    <server>
      <name>Server1</name>
      <hostAddress>127.0.0.1</hostAddress>
      <hostPort>2905</hostPort>
      <!-- ... -->
    </server>
  </servers>
  <associations>
    <entry>
      <key>Assoc1</key>
      <value>
        <name>Assoc1</name>
        <hostAddress>127.0.0.1</hostAddress>
        <hostPort>2906</hostPort>
        <peerAddress>127.0.0.1</peerAddress>
        <peerPort>2907</peerPort>
        <!-- ... -->
      </value>
    </entry>
  </associations>
</SctpPersistData>

Key Implementation Notes

• SctpJacksonXMLHelper configures an explicit WstxInputFactory / WstxOutputFactory for consistent StAX behavior
• SctpPersistData uses @JsonDeserialize annotations to preserve generic type information for List<Server> and Map<String, Association>
• Both NIO (ManagementImpl) and Netty (NettySctpManagementImpl) paths share the same Jackson XML binding layer

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🧬 Technical Deep Dive

Why JCTools MpscArrayQueue?

Feature	Benefit
Lock-free	No contention, no blocking
MPSC	Multi-producer (threads), single-consumer (selector)
Cache-friendly	False-sharing protection
GC-friendly	Pre-allocated, zero-allocation hot path

Adaptive Pool Sizing

// Monitors hit rate every 10K operations
if (hitRate < 0.70) {
    // Pool too small, increase by 25%
    preallocateAdditional(capacity / 4);
}

Release Guarantees

try {
    process(payload);
} finally {
    pool.release(payload); // Always executed
}

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📝 Changelog

v2.0.13 (Current) - "Jackson Persistence"

• 🔧 Fixed: Jackson XML deserialization with explicit Woodstox factory configuration
• 🔧 Fixed: Added @JsonDeserialize annotations for List<Server> and Map<String, Association> type info
• 🔧 Fixed: Various Netty association and management stability fixes
• ✅ Added: woodstox-core dependency for StAX compatibility on Java 8 / WildFly 10
• 🎨 Improved: Replaced XStream with Jackson XML for Java 17 compatibility

v2.0.8 - "Pool Perfection"

• 🔧 Fixed: All objects now pooled (removed non-pooled fallback)
• 🔧 Fixed: Pool-miss objects returnable to pool
• 🎨 Improved: .gitignore for AI dev environments

v2.0.7 - "No Fallback"

• ❌ Removed: new PayloadData() fallback
• ✅ Guaranteed: 100% pool utilization

v2.0.6 - "Zero Copy"

• ✅ Added: PooledByteBufAllocator integration
• ✅ Added: Zero-copy in NIO and Netty paths
• ✅ Fixed: Release in all 3 paths (single-thread, Worker, Netty)

v2.0.5 - "Pool Birth"

• ✅ Initial: PayloadDataPool with MpscArrayQueue
• ✅ Feature: Adaptive sizing

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🌟 Why Upgrade?

If you're running:

• Diameter (Gx, Rx, S6a, S13) → SCTP-NG eliminates latency spikes
• SIGTRAN (M3UA) → SCTP-NG handles 10x more associations
• VoLTE/IMS → SCTP-NG provides consistent sub-ms latency

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📄 License

GNU Affero General Public License v3.0

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Crafted by: nhanth87 Powered by: JCTools 4.0.3 | Netty 4.2.11.Final | Java 11
Mission: Zero-GC telecom infrastructure

sctp