Low-cost Optical Network Upgrade: Turn Switch/Router into OLT with One Module? How?

No need to replace core switches or purchase costly OLT chassis. Simply insert a dedicated module into the SFP port, and the device gains full OLT capabilities.

Many SMEs, hotels and parks tend to wonder when planning all-optical network construction:

Do we have to discard all existing switches?

Is it necessary to spend tens of thousands on a dedicated OLT chassis?

The answer is negative.

If you own switches, routers or firewalls equipped with SFP/SFP+ ports, only a modular OLT is needed to build a complete PON all-optical network.

This article illustrates how to convert common data communication devices into functional OLTs at the lowest cost and within the shortest time for all-optical network renovation.

1. Pain Points of Traditional All-optical Upgrade: High Cost, Complexity and Vendor Lock-in

Before modular OLT came out, small-scale all-optical network construction faced limited options, covering hotels with 60 rooms, office floors with 40 workstations and parks with 8 buildings.

Purchase dedicated OLT chassis

Even 4-port or 8-port box-type OLT costs thousands to tens of thousands yuan. It occupies 1U-2U cabinet space and requires independent power supply.

Master new configuration logic

Traditional OLT features exclusive command lines, VLAN mapping modes and bandwidth templates, differing from conventional switch configuration methods.

Restricted by vendor ecosystem

ONU devices are recommended to match the OLT brand to avoid compatibility issues, leaving capacity expansion limited to the same manufacturer.

Such drawbacks hinder SMEs from adopting all-optical networks due to excessive costs and technical barriers.

2. Innovative Solution: Module Replaces Chassis

The emergence of modular OLT, also known as vOLT or pluggable OLT, reshapes the industry pattern.

Its core concept is straightforward: all OLT functions are integrated into a standard SFP/SFP+ optical module.

The module embeds PON MAC, PHY, DBA scheduling, FEC error correction, AES encryption and OMCI protocol stack. Adopting standard SFP+ pins, it boasts wide compatibility and works with any switch, router or firewall equipped with standard SFP/SFP+ ports.

In short, no dedicated OLT chassis is required. Only a module-style OLT is needed.

Insert it into the SFP port of existing switch, and the port will instantly serve as a fully functional PON port.

Traditional Solution VS Modular OLT Solution

III. Implementation Steps: Upgrade in Three Steps

Take AINOPOL ZH-VOLT series as example, the operation is simple.

Step 1: Inspect existing devices

Select devices equipped with SFP or SFP+ ports, such as:

Enterprise switches (Cisco, Huawei, H3C, MikroTik, TP-Link, etc.)

Optical-port routers

Optical-port firewalls

Only one requirement: the SFP port supports matched speed.

GPON modules like ZH-VOLT32 require 1G or 2.5G compatible ports

XGPON modules like ZH-VOLTXG64 require SFP+ ports

Most gigabit SFP and 10G SFP+ ports meet the standards, with actual compatibility rate over 95%.

Step 2: Insert modular OLT

Plug ZH-VOLT module into the SFP port just like a common optical module.

The module powers on, runs self-check and initializes PON protocol stack automatically. No driver installation or manual configuration is needed.

Step 3: Connect splitter and ONU

Link the module port to 1:4, 1:8, 1:16 or 1:32 optical splitter via fiber patch cord.

Connect each branch port of the splitter to ONU devices in rooms and workstations.

The module automatically detects, registers and manages all connected ONUs after power-on.

The switch is now fully functional with complete PON capabilities. Ports originally for common optical modules can connect dozens of ONUs just like standard OLT ports.

IV. Core Advantages

Lower deployment costs

Ultra-simple deployment and maintenance

Plug-and-play with zero commissioning. The module is identified and initialized automatically after insertion. Data is fully transparently transmitted without CLI or network management configuration. ONUs get registered automatically upon power-up with no manual operation required, eliminating reliance on professional PON technicians.

Flexible capacity expansion by adding modules

Traditional OLT chassis have limited ports, requiring service board or even chassis replacement for expansion.

Modular OLT scales along with existing switches:

24-port switch supports up to 24 PON ports

48-port switch supports up to 48 PON ports

Start with 4 modules for 4 floors, and add another 4 modules later to cover extra floors. Purchase and deploy modules on demand.

FAQ

Q1: Is the module compatible with regular switches? Any configuration adjustment needed?

Yes. It works with most standard SFP/SFP+ ports. No configuration changes are required. Full VLAN transparent transmission is enabled by default for plug-and-play use.

Q2: How many ONUs can one module carry?

AINOPOL models support respective capacities: ZH-VOLT16 for 16 ONUs, ZH-VOLT32 for 32 ONUs, ZH-VOLT64 and XGPON ZH-VOLTXG64 for 64 ONUs. The maximum capacity reaches 64 ONUs per module.

Q3: Can it replace existing common optical modules directly?

Yes. Remove the original module and insert the modular OLT, then reconnect optical fibers. Note that it shall connect to ONUs or optical splitters instead of peer optical modules in point-to-point mode.

Q4: Are matched-brand ONUs mandatory?

Not necessary. Built-in standard OMCI protocol ensures around 95% compatibility with mainstream standard HGU ONUs. Technical adaptation support is available for incompatible devices.