Technology Support
Fiber Optic Communication Series - 4: The Rise of PON Technology
PON Technology Types
Key deployed PON standards: EPON and GPON. Legacy systems include APON/BPON. Core differences lie in data link layer protocols.
APON/BPON
- Developed by FSAN consortium in the mid-1990s (ITU-T G.983 standard).
- Initially ATM-based (APON), later renamed BPON to reflect multi-service support (Ethernet, video).
- Limitations: Incompatible with variable-length IP packets, complex, low efficiency.
- Status: Phased out due to IP network dominance.
EPON (Ethernet PON)
- Combines PON topology with Ethernet protocol (IEEE 802.3).
- Advantages:
- Native IP support (variable-length packets)
- Low cost, high bandwidth, flexible deployment
- Seamless integration with existing Ethernet networks
- Market Position: Widely deployed in Asia, mature ecosystem.
GPON (Gigabit-capable PON)
- Standardized by ITU-T G.984 series (2003-2004).
- Key Innovation:
- Uses GFP (Generic Framing Procedure) to encapsulate Ethernet/TDM/ATM into GEM frames.
- Supports variable-length packets and multi-service delivery.
- Advantages:
- Higher bandwidth (2.5G down / 1.25G up asymmetrical)
- Enhanced OAM, strict QoS, larger split ratios (up to 1:128)
- Carrier-grade reliability
EPON vs. GPON Comparison
| Criteria | EPON | GPON |
|---|---|---|
| Bandwidth | 1 Gbps symmetric | 2.5 Gbps down / 1.25 Gbps up |
| Protocol | Native Ethernet (IEEE 802.3) | Multi-service (GEM encapsulation) |
| Cost | Lower CAPEX/OPEX | Higher initial cost |
| OAM & QoS | Basic | Advanced (carrier-grade) |
| Market Fit | Cost-sensitive deployments | High-bandwidth/multi-service needs |
Key Takeaways
- Legacy: APON/BPON obsolete due to IP incompatibility.
- EPON: Optimal for Ethernet-centric, budget-conscious networks.
- GPON: Superior for high-bandwidth, multi-service, and carrier environments.
- Coexistence: Both EPON and GPON serve complementary roles; GPON adoption grows but no full replacement.
