Let me start out by explaining exactly what a metropolitan area network (MAN) is. Basically, it refers to a computer network that interconnects other local networks across an entire metropolitan region or city. As you read this guide, I’ll cover everything you need to know about MANs including what they’re used for, how they work, challenges with them, and how they differ from local and wide-area networks. My goal is to provide you with a comprehensive, practical understanding of this important but often misunderstood type of networked infrastructure.
Overview
- MANs connect local area networks (LANs) across a metro region of usually 2-25 miles
- Provide high-speed localized communication and transfer data
- Connect government agency offices, university campuses buildings, local ISPs
- Rely on fiber optic or coaxial cabling able to span long distances
- More expensive to implement than LANs or WANs but serve a key role
Now that you have the 30 second overview, let’s explore the details…
Common Use Cases and Examples
While not as ubiquitous as the LANs and WANs that connect most modern devices and systems, MANs still serve vitally important networking functions for key use cases:
1. Government Agencies
The most common application is connecting agency offices and buildings for city, state, or federal government entities. For example, a state government may have dozens of offices and agencies scattered across a metro area that need to intercommunicate and share regional resources. A MAN allows this without relying on the broader internet.
According to surveys, over 80% of city IT managers state that their MAN is crucial for daily government operations.
2. Educational Campuses
Schools and universities also implement MANs across sprawling campuses, usually referred to as campus area networks (CANs). These connect dorms, libraries, auditoriums, sports facilities and admin buildings for highly localized student access.
The University of Texas at Arlington, as one example, has a MAN connecting over 50 buildings across 420 acres for fast, targeted on-campus communication.
3. Local ISPs
Some regional and local internet service providers establish MANs rather than relying on large national ISPs. This allows them to tailor connectivity to a particular area without traffic leaving the metro region.
According to FCC reports, over 75 regional and local ISPs currently operate MANs serving various metropolitan cities rather than leasing infrastructure from large providers.
While government, academia and local ISPs make up the bulk of MAN usage, the high-speed, localized nature of MANs lends them useful for any large organization spanning a geographic metro region.
Technical Architecture and Infrastructure
MANs require an extensive infrastructure investment to connect LANs across areas up to 25 miles wide:
Cabling
Most MAN cabling consists of high-bandwidth fiber optic or coaxial cables rather than standard Ethernet. This allows signals to travel longer regional distances without degradation. Over 75% of existing MANs use fiber, with coaxial making up the rest according to various industry estimates.
Equipment
The endpoint devices in a MAN include specialized routers, switches and modems capable of adapting to the MAN’s geographic scale. Configuring networking equipment to operate reliably over miles rather than feet requires precise adjustments.
Expense
Between cabling and equipment, building out a MAN costs over $2 million per mile on average. For a MAN servicing a 20 mile metro radius, the infrastructure costs can easily eclipse $40 million. Ongoing operation and management also requires a dedicated budget.
As you can see, creating the backbone for a functional MAN is no small feat. The costs involved mean they are only practical for large organizations like governments and universities rather than small and mid-sized businesses.
Next we’ll look at some of the downsides and challenges…
Difficulties and Disadvantages
While MANs fill an important connectivity niche, they come with a variety of inherent challenges:
- Congestion from localized traffic
- Infrastructure costs measured in the millions
- Covering a limited 25 mile radius
- Ongoing difficultly of managing and maintaining such a sprawling network
Congestion
With many buildings and LANs funneling communication through a MAN, network congestion during peak times is common. Careful monitoring and traffic shaping techniques must be employed to keep data flowing smoothly.
Expensive to Scale
Expanding a MAN’s geographic reach requires substantial new cabling and equipment investments. Building out additional metro radius coverage is often cost prohibitive.
Limited Area
Despite expansive infrastructure costs, even the largest MAN only extends 25 miles from a central hub. Their range pales in comparison to continental WANs.
Resource Intensive Upkeep
Maintaining consistent uptime and performance across miles of cabling, routers and switches requires extensive ongoing resources. Given their widespread infrastructure, MANs are far more resource intensive to manage than a typical LAN.
With the disadvantages spelled out, you may be wondering in which situations MANs offer the most value. Read on for a comparison to other network types…
Metropolitan Area Networks vs. LANs and WANs
It‘s important to understand where MANs fit compared to local area networks (LANs) and wide area networks (WANs). Here is a helpful comparison table:
| LAN | MAN | WAN | |
|---|---|---|---|
| Area Covered | Up to 1 mile radius | Up to 25 mile radius | Continental or Global |
| Speed | Very High | High | Medium |
| Common Uses | Office networks, homes | Government agencies, campuses, local ISPs | Public internet, connecting global networks |
| Setup Expense | Low | Very High | High |
| Ongoing Expense | Low | High | Medium |
As you can see, MANs strike a balance between localized coverage, speed, and infrastructure expenses. They serve connectivity needs that are more regional than WANs but more extensive than LANs.
When high speed communication across a metropolitan region is needed by institutions like governments, MANs present the ideal solution. But they require substantial investments of money and effort to implement.
Conclusion and Summary
I hope this guide has helped explain exactly what metropolitan area networks are, their technical architecture, primary use cases, disadvantages, and how they compare to other network classifications.
Here are the key takeaways:
- MANs fill a networking connectivity niche between local and wide-area networks
- Connect government, academia and local ISP infrastructure across a metro
- Provide high speed communication across 2 to 25 mile regions
- Require expensive fiber and coaxial cabling buildouts
- Come with congestion, scaling, range and maintenance challenges
- Deliver value for institutions needing reliable localized networking
While hidden from most peoples’ day-to-day internet usage, MANs serve a key role in networking the infrastructure of metropolitan regions. Local governments and universities rely extensively on MANs designing exclusively for a city or campus’ needs. They come with downsides and expenses exceeding most organizations’ budgets. But for the right applications, MANs facilitate key communication that other networks struggle to deliver.
I hope this guide has left you with a complete picture of this less common but still vital component of our networked infrastructure. Let me know if you have any other questions!
