As our appetite for digital services continues to grow exponentially, the demand for faster, more reliable network connections shows no sign of slowing down. Among the technologies powering our digital infrastructure, optical wavelengths stand out as a fundamental building block offering exceptional performance. Let’s dive into what optical wavelengths actually are, their key benefits for latency and frame size capabilities, and how they stack up against alternatives like MPLS.

What Is an Optical Wavelength?

An optical wavelength (or simply a “wavelength” in telecoms parlance) is essentially a dedicated channel of light within a fibre optic cable that carries data. Using Dense Wavelength Division Multiplexing (DWDM) technology, multiple wavelengths—each operating at different frequencies—can travel simultaneously through a single fibre strand, with each wavelength carrying its own independent data stream.

I like to think of an optical fibre as a motorway and wavelengths as dedicated lanes. Each lane can carry traffic at extremely high speeds without interference from other lanes. This creates a direct, point-to-point connection between locations with enormous bandwidth capacity.

Key Benefits of Optical Wavelengths

Ultra-Low Latency

One of the biggest advantages of optical wavelengths is their remarkably low latency. Since data travels at the speed of light through dedicated channels with minimal processing overhead, wavelength services can achieve latency as low as 5 microseconds per kilometre.

This near-instantaneous transmission makes wavelengths perfect for:

• High-frequency trading platforms where nanoseconds make all the difference
• Real-time applications like telemedicine
• Interactive cloud services
• Time-sensitive industrial automation

Jumbo Frames and High MTU Support

Standard Ethernet frames are limited to 1,500 bytes. However, optical wavelengths support jumbo frames—Ethernet frames with sizes exceeding the standard limit—often allowing packets up to 9,000 bytes or more. This higher Maximum Transmission Unit (MTU) capability brings several advantages:

• Reduced overhead: Fewer frames means less processing time and header overhead
• Improved throughput: Networks can achieve higher effective throughput
• Enhanced efficiency: Better performance for large data transfers like backups or database operations

Massive Bandwidth Scalability

Modern optical wavelength technology provides enormous bandwidth, with individual wavelengths commonly offering 100Gbps, 400Gbps, and even pushing toward terabit capacities. This scalability makes wavelengths brilliant for:

• Data centre interconnects
• Carrier backbone networks
• Cloud connectivity
• Large enterprise networks with hefty bandwidth demands

The Unprotected Nature of Wavelengths

Despite their performance benefits, traditional wavelength services come with an important limitation: they’re typically unprotected. Unlike some network services that offer built-in redundancy, a basic wavelength service operates over a single fibre path. If that path is compromised (through fibre cuts, equipment failures, or other issues), the connection is lost.

That said, for critical applications requiring high availability, RODAM (Reconfigurable Optical Add-Drop Multiplexer) technology offers a solution. When dual fibre paths exist between locations, RODAM can enable optical switching to redirect traffic almost instantaneously in case of failure, typically within 50ms. This provides protection at the optical layer without introducing the additional latency that upper-layer protection mechanisms might incur.

Wavelengths vs. Layer 2 MPLS (Ethernet Wireline)

To better understand when wavelengths are the right solution, let’s compare them with Layer 2 MPLS services, also known as Ethernet wireline:

Advantages of Wavelengths over MPLS

1. Lower Latency: Wavelengths typically offer significantly lower latency as they provide direct optical paths without the additional processing of MPLS labels.
2. Higher Bandwidth: Individual wavelengths can offer higher bandwidth than many MPLS services, with simpler scaling to hundreds of gigabits.
3. Protocol Transparency: Wavelengths can carry any protocol, not just Ethernet, making them more flexible for specialised applications.
4. Deterministic Performance: With dedicated capacity, wavelengths offer more consistent performance without the potential variability of shared MPLS networks.

Advantages of MPLS over Wavelengths

1. Built-in Protection: MPLS networks typically offer built-in protection and rerouting capabilities without requiring specialised optical switching equipment.
2. Network Flexibility: MPLS allows for many-to-many connectivity rather than just point-to-point, making it more suitable for complex network topologies.
3. Service Integration: MPLS can integrate multiple services (voice, video, data) with differentiated quality of service on a single platform.
4. Cost Efficiency for Lower Bandwidths: For connections requiring less than gigabit speeds, MPLS may offer a more cost-effective solution than dedicated wavelengths.

When to Choose Wavelengths

Optical wavelengths are typically the right choice when:

• You absolutely must have minimum latency
• You need very high bandwidth (10Gbps+)
• You’re connecting major data centres or key infrastructure
• You require protocol transparency
• You need support for jumbo frames
• A direct point-to-point connection does the job

References

1. Cisco Systems. (2023). “Optical Networking Fundamentals.” Cisco Documentation. [Available from Cisco.com]
2. Kartalopoulos, S. V. (2022). “DWDM: Networks, Devices, and Technology.” IEEE Communications Society, IEEE Press.
3. Thyagarajan, K., & Ghatak, A. (2021). “Fibre Optic Communications: Fundamentals and Applications.” Springer International Publishing.

By understanding the unique characteristics of optical wavelengths and comparing them with alternatives like MPLS, network architects can make informed decisions about which technology best suits their specific requirements, balancing performance, protection, and cost considerations.