The Difference Between Long-Haul vs. Metro Networks

Based on the latest IoT Analytics report, the global count of connected IoT devices is projected to reach 16.7 billion active endpoints by 2023, reflecting an era of unparalleled connectivity. In this interconnected world, stable and high-speed data transmission is indispensable for organizations, businesses, and individuals. Long-haul and metro optical transport networks play a pivotal role in realizing this vision of the Internet of Everything. However, understanding the distinctions between long-haul and metro networks can sometimes be ambiguous due to the evolving nature of network definitions. Let's delve deeper into these differences.

What Are Long-Haul Networks?

Long-haul networks form the backbone of the global network infrastructure, delivering high-bandwidth connectivity across extensive distances, often spanning countries or continents. These networks are engineered for rapid and reliable data transmission, leveraging high-capacity fiber optic cables, long-haul transceivers, and cutting-edge networking technologies.

Key players in the long-haul network sector include AT&T, Verizon, and China Telecom Global, which provide these critical services. By leveraging long-haul networks, businesses and individuals can efficiently transmit large volumes of data over vast distances, a necessity in today's interconnected digital landscape. Long-haul networks, primarily dominated by a select group of multinational carriers, serve as the vital link connecting metro networks.

What Are Metro Networks?

Metro networks, also called metropolitan area networks or MANs, are engineered to deliver high-speed connectivity within specific geographic regions, typically metropolitan areas or cities. These networks interconnect multiple Points of Presence (POPs) within the same locality, facilitating efficient data transmission.

The MAN leverage a combination of fiber optic cables, copper cables, short-reach transceivers, and wireless technologies to achieve rapid and dependable data transmission across limited distances.

Prominent MAN providers include CenturyLink, Windstream, and Zayo. These networks are vital in keeping businesses, organizations, and residential users seamlessly connected within their local environments.

Metro networks can range from singular networks supporting services like wired Internet connections for television to expansive networks comprising interconnected Local Area Networks (LANs).

What Technology Does Long-Haul And Metro Networks Use?

Coherent Technology

Coherent optical technology is at the forefront of the industry's push to achieve transport speeds exceeding 100G, enabling the transmission of Terabits of data over a single fiber pair. Through the use of digital signal processors, it electronically compensates for Chromatic and Polarization Mode Dispersion (CD and PMD), ensuring robust performance over both existing and new fiber infrastructures. This eliminates the necessity for dispersion-sloped compensating modules within the photonic line.

Moreover, coherent optics enhances network flexibility and programmability by supporting various baud rates and modulation formats. This enhanced flexibility extends to line rates, allowing scalability from 100G to 400G. Consequently, this advancement delivers increased data throughput at a reduced cost per bit, driving efficiency and performance within optical communications.

ROADM

ROADM (Reconfigurable Optical Add-Drop Multiplexer) is a cutting-edge technology that establishes direct optical routing between senders and receivers without passing through intermediate core switches. Within a ROADM ring, optical signals travel directly to their designated destination nodes. If a node is not the intended recipient, the wavelength is directed to a preconfigured exit port for routing. Upon reaching the desired nodes, the wavelength is dropped by a Wavelength Selective Switch (WSS) and connected to the corresponding transceiver without introducing transmission delays. This streamlined approach optimizes the efficiency and speed of data transmission within optical networks.

WSS

The wavelength selective switches (WSS) feature cutting-edge Liquid Crystal on Silicon (LCoS) technology, offering highly granular spectral control down to 6.25GHz. They support various transmission data rates, including 10Gb/s, 100Gb/s, 400Gb/s, and super-channels, enhancing spectral efficiency and reducing operational costs.

These WSS modules are available in single or twin configurations with varying port capacities: 9 ports, 20 ports, and 35 ports. They are designed to be colorless/directionless (CD) to enhance network flexibility, enabling route-and-select configurations that support drop-path filtering and improve port isolation.

What Is The Difference Between Long-Haul vs. Metro Networks?

Geographic Coverage & Transmission Distance

As the name suggests, long-haul networks cover expansive geographic regions, often spanning entire regions or countries. In contrast, metro networks are tailored for smaller geographic areas, typically encompassing a city or town. Long-haul networks are optimized for transmitting data over significant distances, generally from 1000 to 2500 km. On the other hand, metro networks handle data transmission over relatively shorter distances, typically from 80 km to 1000 km.

QSFPTEK offers optical transmission solutions designed to meet the needs of both metro and long-haul networks, such as 100G PAM4 solutions for 100G metro networks, or ultra-long distance solutions with 200G/400G coherent technology. It's important to note that different countries or regions may have varying definitions of transmission distances, necessitating context-specific analysis. QSFPTEK provides sample testing and customized solutions to address these nuances effectively.

Network Capacity

Network capacity denotes the maximum data transmission rate within a specific timeframe in optical communication. Long-haul networks boast a higher capacity than metro networks, enabling them to manage large data volumes over extensive distances. Although proficient in handling substantial data traffic, Metro networks generally possess a lower capacity than their long-haul counterparts.

Dense Wavelength Division Multiplexing (DWDM) technology plays a crucial role in the enhanced capacity of long-haul networks. DWDM permits multiple light wavelengths to traverse a single optical fiber simultaneously. Long-haul networks leverage DWDM to transmit multiple data streams concurrently over the same fiber, each utilizing a distinct light wavelength. This advancement has empowered long-haul networks to achieve exceedingly high capacities, with some networks capable of transmitting terabits of data per second through a single fiber.

Utilizing long-reach transceivers can extend the reach of long-haul networks without requiring additional amplification. When paired with DWDM technology, long-haul transceivers further augment the capacity and efficiency of these networks.

This heightened capacity equips long-haul networks to support a diverse range of applications while minimizing the necessity for additional physical infrastructure, enhancing cost-effectiveness and efficiency.

In Metro networks, transmission typically covers distances up to 120km, whereas Long-haul networks span several hundred kilometers. Coherent technology is widely employed for longer distances. Regular DWDM modules have a transmission capacity of up to 100G, whereas coherent single-wave systems can achieve speeds of 400G.

Latency

Latency represents the delay or lag experienced during data transmission across a network. Compared to older network technologies, long-haul and metro networks exhibit low latency. However, long-haul networks typically exhibit higher latency due to the greater distances involved than metro networks. While the speed of light remains constant in a vacuum, it slows down as it traverses through an optical fiber, which can contribute to increased latency over extended distances.

Conclusion

In conclusion, long-haul and metro networks play vital roles in the global network landscape to manage the increasing volume of network traffic. Long-haul networks excel in transmitting data across extensive distances, while metro networks specialize in connecting locations within a metropolitan area. 

Different industries have unique requirements for their network solutions. As a leading global networking innovator, QSFPTEK offers professional network solutions and a range of suitable products, including short-reach and long-reach transceivers. Whether you're looking to upgrade your existing network infrastructure or establish a new network from scratch, QSFPTEK provides comprehensive solutions tailored to your needs. Contact us today to find the solution that aligns perfectly with your requirements!