A Metropolitan Area Network
A computer network that links several computers or local area networks (LANs) in a geographic region that is bigger than a LAN but smaller than a wide area network (WAN) is called a metropolitan area network (MAN). The word “metropolitan” does not necessarily relate to the network’s location in an urban region; MANs can also service rural areas. Rather, it describes the network’s potential size or reach.
Scope and Purpose
Geographical Coverage: A Metropolitan Area Network usually includes a city or town and covers an area of a few miles to fifty km. They can go up to 100 km, according to some accounts. Their purpose is to cover a certain region, such as a city or a small suburb.
Primary Purpose: Connecting various LANs inside a city is the primary goal of a Metropolitan Area Network in order to make data interchange and computer resource sharing easier. They can give consumers in a metropolitan region with high-speed internet access and high-speed data transmission services, such as video, audio, and general data transfer.
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Metropolitan Area Network Characteristics
High Speed: MANs, which frequently use fiber-optic cables, are made for high-speed data transport. The range of speeds is 10–100 Mbps. Depending on the technology, they may be marginally slower than small LANs, even though they are often quicker than WANs.
Reliability: Because of their extremely low mistake rate, they provide exceptional dependability.
Scalability: MANs may be readily expanded to handle more users and increasing network needs.
Connectivity Options: Numerous access methods, including fiber-optic, copper-based, and wireless connections, can be used by a Metropolitan Area Network. In order to connect LANs across shorter distances inside the metropolitan region, they can also incorporate various wireless technologies, such as Wi-Fi or microwave connections.
Topology: Depending on particular network needs, a Metropolitan Area Network network may combine several topologies, including a ring, bus, or star architecture. Both channels of concurrent data transfer are made possible by dual bus design.
Metropolitan Area Network History
Early Development: Businesses first used public switched telephone networks to connect LANs inside a city by 1994, when LANs were widely used. However, the huge traffic needs of LANs were too much for these phone networks to handle.
Fiber Optics: It was proposed that single-mode optical fiber lines, which were already being used for long-distance phone trunks, be used to connect LANs in order to get around these restrictions. These early fiber optic MANs were not completely connected with public WANs and were frequently owned and run by private entities. Dark fiber was also used for MAN backbones by academic institutions and research centers, such as the BERCOM project in West Berlin during the 1990s.
Technological Advancements: The growth of MANs was further accelerated in the 2000s by the effective use of dense wavelength-division multiplexing (DWDM), which made it possible to divide existing fibre optic MANs into multiple wavelengths, supporting large bandwidths and a variety of protocols and lowering their construction and maintenance costs.
Metro Ethernet: Using a fiber optic ring as a Gigabit Ethernet MAN backbone, Metro Ethernet came into being. Data rerouting is made possible by this technology in the event of failure or congestion. For example, between 2002 and 2003, Sprint Corporation constructed many Metro Ethernet rings throughout Silicon Valley. In order to standardize and define best practices for these networks, the Metro Ethernet Forum (MEF) has been important.
Metropolitan Area Network Architecture
A Metropolitan Area Networks are often a collection of several LANs that are linked together via backbone fiber optic cables. High data speed is made possible by leasing “dark fiber” previously unused fiber optic cables from commercial ISPs to create these connections. Sometimes, after constructing and maintaining metropolitan fiber optic networks, municipal governments lease dark fiber to private businesses.
There are several layers involved in the building process:
Network Infrastructure
- Core Layer: For central network connectivity and data flow control, high-capacity fibre optic connections and robust routers and switches are often used.
- Distribution Layer: Prepares information from many sources to be sent to end users or the core layers.
- Access Layer: Consists of switches, routers, and other hardware that connects end users or particular LANs to the MAN directly.
Internet and External Connection: In addition to managing data routing, security, and occasionally load balancing, devices such as gateways and routers oversee connections between the MAN and other external networks or the larger internet.
Network Management and Security: Systems and tools are put in place to keep an eye on any problems, traffic trends, and network performance. Numerous security precautions are put in place, including VPNs, firewalls, and encryption.
Redundancy and Failovers: In addition to disaster recovery plans, critical components frequently include backup systems to guarantee ongoing functioning in the event of problems.
Scalability and Flexibility: As user or organizational demands change, networks may easily be expanded or reconfigured because to their modular nature. Ethernet, wireless, and optical communications are among the technologies that MANs can handle.
Ownership and Management
Large organizations (such corporations or universities) may privately own a Metropolitan Area Network, a network service provider that offers connection services may administer it, or a group of users, a city, or the local government may own it. More and more municipal ISPs are using MAN technology and leasing networks to private internet service providers. MANs can be either locally or centrally controlled.
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Benefits of Metropolitan Area Network
High-Speed Connectivity: Provides 10-100 Mbps speeds, allowing for quick communication and data transfer.
Enhanced Security: Offers a more stringent and high degree of security than WANs.
Resource Sharing: Enables effective resource sharing between several LANs, including servers, storage devices, and printers.
Centralized Management: Simplifies administration and monitoring by enabling centralized management and control of network resources.
Cost-Effectiveness: Can be less expensive than using a WAN to connect several LANs, especially when data volumes are considerable. When opposed to pricey leased lines, wireless MANs (WMANs) can also result in considerable cost reductions.
Supports Multiple Users: Able to provide high-speed internet connection to several users at once.
Disadvantages of Metropolitan Area Network
Complexity: Because of its intricate construction, MANs are challenging to design and maintain, requiring specialized staff.
High Cost: Because fiber optics setup is costly and requires high-speed equipment and infrastructure, A Metropolitan Area Network implementation and maintenance can be costly.
Security Risks: Strong security measures are required since MANs are susceptible to security risks such malware, hacking, illegal access, and data breaches.
Fault Tolerance: Generally speaking, they provide less fault tolerance.
Scalability Issues: Congestion may arise when the network expands and more users are added, resulting in problems with performance.
Interoperability: Interconnection might be difficult because different LANs inside a Metropolitan Area Network may employ different technologies and protocols.
Latency: Network performance and speed may be impacted by latency caused by the separation between linked LANs.
Bandwidth Limitations: High-bandwidth applications like video conferencing may not be supported by MANs due to the bandwidth limitations of their underlying infrastructure.
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Examples and Applications
- MANs are used by cable TV networks to disperse their services throughout a city.
- Within a metropolis, corporate networks link several office locations.
- Within a city, different departments and organisations are connected by government networks.
- University campuses allow for resource sharing and collaborative learning by connecting many facilities located around a metropolis.
- Healthcare systems facilitate telemedicine and patient data management by connecting clinics and hospitals.
- MANs are used in smart city projects to link elements like environmental sensors, public Wi-Fi hotspots, and traffic control systems.
- Coordination between emergency services is improved by public safety systems.
- Delivering a supplementary communication channel for disaster recovery as well as backup and recovery services for data across several LANs.
Comparison with Other Networks
LAN (Local Area Network): LANs, which usually encompass a single building or office, are much smaller than MANs. Although MANs have more geographic coverage than extremely local LANs, several sources point out that their data transmission speeds can be inferior.
WAN (Wide Area Network): WANs may cover whole nations or continents, whereas MANs are more localized and smaller. To get access to larger networks, such as the internet, MANs can be linked to WANs, frequently via gateways or routers.
CAN (Campus Area Network): A CAN is a large network that links several campus buildings. A Metropolitan Area Network covers a larger metropolitan area, but a CAN is usually limited to a smaller, more specialized location, such as a university or corporate campus, although having a comparable scope. If campus networks link several LANs but aren’t large enough to be categorized as WANs, they can be categorized as MANs.
Additional Information
Internet Exchange Points (IXs): IXs have historically played a key role in linking MANs to the national or international Internet. Low-latency connectivity between campus networks and data exchange between metro Ethernet providers and national carriers are made possible by metropolitan Internet exchange points like Boston MXP, Seattle IX, London Internet Exchange (LINX), and Amsterdam Internet Exchange (AMS-IX). By retaining data in the metropolitan region, they assist local carriers in lowering their transit costs.
Quality of Service (QoS): To guarantee less jitter and delay, MANs can prioritize specific traffic types (such as voice or video) using QoS features. Techniques like bandwidth allocation, packet prioritisation, and traffic shaping can help achieve this.
Wired vs. Wireless MAN (WMAN): Wireless MANs (WMANs), which rely on radio frequencies for communication, offer greater flexibility and perhaps lower initial setup costs than wired MANs, which primarily employ fibre optic cables for high-speed connectivity. However, depending on line-of-sight, WMAN dependability varies.