What is a wide area network?

A wide area network (WAN) is a communication network that connects geographical dispersed locations across cities, countries or even continents. In one of its common implementations, a wide area network connects an organization’s local area networks (LANs) to one another.

Wide area networks vary in complexity depending on the number of locations to be connected, the distance between locations, bandwidth requirements, reliability, and security. They can range from a connection between an individual user and his/her simple cloud services such as an image storage host or Gmail account server to large networks connecting thousands of locations and data centers.

Wells Fargo, for example, has over 8, 000 branches and 30,000 ATMs that are connected by a complex wide area network. Such bank networks have stringent security and reliability requirements. This is because attempts at robbing banks are increasingly moving away from physical break-ins to cyber-attacks. The recent attack on the Central Bank of Russia that led to a loss 21 Billion Rubles ($31 Million) is a fresh reminder of why tight security on bank wide area networks is imperative.

Reliability of bank networks ensures that networks are always available, with minimal downtimes, to ensure that customers can access, transfer or withdraw their money whenever they need to do so.

Retail chains, medical centers, government departments and educational institutions all rely on different forms of wide area networks for collaboration, sharing of resources and for electronic commerce.   Almost every country in the world, for example, has a national research and educational network (NREN) – a wide area network that connects colleges and research centers to one another.

The emergence of new bandwidth hungry applications such as videoconferencing, remote diagnostics, video surveillance and many other cloud-based services is driving the development of more high speed wide area networks. One good example is the production of large amounts of genomic data that must be transmitted from laboratories to data centers for storage. By some estimates the quantity of genomic data produced daily is doubling every seven months and 2 to 40 exabytes will be produced annually in the next decade. A genomic company recently leased a wavelength solution from ZAYO Group for such a purpose.

In the following section, several technologies used for wide area networks are discussed.

Wide area networking technologies

There is a wide range of competing technologies for wide area networking. They include the public Internet, leased lines, dark fiber, wavelength solutions, MPLS, Carrier Ethernet and SD-WAN.

The Internet

The least expensive and most accessible wide area network is the Internet. By definition, the Internet is a global network connecting millions of computers. Almost every country in the world is connected to the Internet. As of June 2016, over 50% of the world population or 3.7 Billion people had some access to the Internet, according to Internet World Stats. This makes connecting locations all around the world to share data and online services very easy and cost effective.

But the low cost and ease of access of the public Internet as a wide area network comes with a few caveats. The Internet lacks quality of service (QoS) guarantees making it unsuitable for mission critical applications due to loss of data packets, high latency, jitter and other performance issues. Adverse performance issues of the public Internet are beyond the user’s control.

Because of its public nature, the Internet is the least secure of any wide area network. Cyberpunks, Industrial and government spies can have easy access to data and information transmitted over the network. Recent allegations of the hacking of the US Democratic National Committee (DNC) during the 2016 elections by Russia is one reminder of the potential risks associated with the use of the Internet for the transmission of sensitive information.

Internet based VPNs

To circumvent the security concerns associated with the public Internet, a private virtual network (PVN) over the Internet is a more viable wide area networking alternative to the public Internet A VPN is a network technology used to create a secure network over the Internet or any other private network. VPNs can range in complexity from a point to point connection for connecting a remote client to a secure server to systems used by corporations to allow employees to remotely connect to an Intranet.

Individuals have used VPNs to avoid Internet censorship in countries like China, North Korea, Saudi Arabia and Ethiopia. By using a VPN, the user’s communications are less likely to be intercepted and they can also avoid being blocked from accessing certain websites.

VPN technology employs encryption standards to encrypt data between the connected sites. But while VPNs improve data security, the quality of service of data transmitted over the Internet remains an issue.

Private Wide Area Network Solutions

Private WANs are necessary to improve security and QoS for critical applications. The following are commonly used carrier provided wide area network solutions.

Leased Lines (T1/E1)

A leased line is a private bidirectional dedicated connection between two or more locations. They are used by enterprises and organizations for data, voice or video transmission between locations.

Leased lines are also used for dedicated Internet access between the user and an Internet service provider (ISP). With a dedicated leased line there is no contention, allowing for fixed upload/download speeds that do not fluctuate with number of people connected to the ISP at any given time. Different types of leased lines are available from a wide range of providers.

Leased lines were originally used for voice communications, typically carrying T1 or E1 signals. T1, with a capacity of 1.544 Mbps, is composed of 24 voice channels, each channel being equivalent to a DS0. The European version, E1, is equivalent 32 voice channels and has a capacity of 2.048Mbps. T3/E3 lines with capacity of 44.7/ 34.4 Mbps are also available over traditional leased lines – note that T3 bandwidth is greater than E3 bandwidth.

These leased lines were typically provisioned over pairs of twisted copper in the local loop. The operator would physically connect the copper connecting a customer’s locations by switching signals between them. Today, T1/E1 or T3/E3 signals are also provisioned over optical fiber and other access technologies in the last mile.

Dark Fiber Services

Communication services are becoming more sophisticated, requiring much higher carrying capacity than traditional leased lines can deliver. Enterprises have the option to lease or purchase dark fiber from a network provider or a fiber optic infrastructure company.

Fiber optic has proven to be a more superior medium of communication than copper and wireless media. While the speed of light that carries communication signals in fiber is not that different from the speed of electricity in copper, fiber has much greater frequency range (~4THz in the C-band) than copper cables (~100MHz for CAT5 cable). The abundance of optical frequency bandwidth enables almost limitless capacity in optical fiber. Moreover, immunity to electromagnetic interference and lower signal attenuation makes fiber an even more superior transmission medium for communication signals.

Fiber optics can deliver up to 100Gbps today using a variety of technologies, including 100 Gigabit Ethernet (100GBE) or 100 Gbps Optical Transport Network (OTN). The capacity of optical fiber is limited only by the transmission electronics.

Dark fiber or unlit fiber is installed fiber optic cable or strands that are not in use. The enterprise that leases or purchases dark fiber has the flexibility to use transmission equipment of their choice to deliver services through the fiber. Dark fiber is especially important for organizations that are growing rapidly and want the scalability for point to point connections. The enterprise can easily upgrade bandwidth by upgrading the transmission equipment.

With dark fiber, companies can easily manage technology evolution without having to rely on the network provider. For example, as technology evolved from GbE to 10GbE to 100GbE and from SONET/SDH to OTN, enterprises with access to leased dark fiber could make quick decisions on when to migrate to newer technologies.

But there is one important caveat. Unless a network provider fully manages a company’s dark fiber, the company is responsible for frequent monitoring and repair of the fiber infrastructure. If the fiber is long haul, spanning over 100km, it will require investment in optical amplifiers/regenerators that must be powered and maintained.

While dark fiber is a viable solution for large enterprises, the responsible authorities must have a clear understanding of the operation challenges involved.

Case Study: University of Colorado Health (UCHealth) leased dark fiber

The University of Colorado Health (UCHealth) is a fast-growing health institution with four major hospitals or clinics and has a long-term growth plan through affiliates and the construction of new facilities. The healthcare system is increasingly becoming digital as the institution has resorted to the use of digital services including high-definition imaging and video, telehealth, electronic medical records (EMR), medical laboratory systems and revenue cycle management.

As UCHealth footprint and digital applications continue to grow, so is the bandwidth required to connect their locations. Thus, UCHealth needed a high capacity, scalable, reliable, low latency, and secure wide area network. The institution leased ZAYO dark fiber and wavelength services to boost its wide area network capacity.

Optical Wavelength Services

For many large enterprises with multiple locations and requiring dedicated, high speed transport network connectivity without the need for upfront capital, leasing pairs of fiber strands to each location can be a costly and inconvenient proposal. Optical wavelength services could be a more viable solution.

Using a Dense Wavelength Division Multiplexing (DWDM) network solution, operators can transmit many wavelength channels in a single fiber and route them to different parts of their network. DWDM is an optical communication technology in which multiple wavelengths of laser light are multiplexed onto a single optical fiber strand. In the optical C-band, for example, communication signals can be transmitted at 1528.77nm, 1529.55nm….1567.95nm wavelengths as defined by the International Telecommunication Union (ITU).

Current commercial DWDM systems can transmit up to 128 wavelength channels in a single fiber strand. Each DWDM channel can carry up to 100Gbps with higher data rates of 400Gbps anticipated to be widely available in the market by the 2017/2018 time frame.

By leasing wavelength services from a network operator with a national or global footprint, an enterprise can access high bandwidth at different geographically dispersed locations without the need to lease fiber strands or without the need for upfront CAPEX to deploy their own fiber optic network. Current wavelength services typically deliver bandwidths ranging from 1Gbps to 100Gbps.

Leading network operators offer a variety of technologies over wavelength services to accommodate the client choices. These include SONET/SDH, IP and Ethernet.

Case Study: An information services company wavelength services

A large information services company offering information, news, and technical solutions to the financial community in several market segments – legal, tax, accounting, healthcare, science, and media – needed high bandwidth and reliable connectivity between two of their data centers. The company also needed redundancy to ensure that there was no outage in connectivity between the data centers separated by 1,000 miles.

The company selected XO Communications to provide a reliable wavelength service over XO’s US nationwide fiber optic network. The solution was a fully managed two 10 Gbps wavelengths with Ethernet handoffs to connect the data centers.

XO is one of the leading network providers serving 85 markets in the United States. Through partners, the XO network extends to more than 50 countries including UK, The Netherlands, Germany, Hong Kong, and Canada. XO owns 1.5 million optical fiber strand miles in its network, including about 20,000 route-miles of long-haul and 13,500 route-miles of metro fiber.  XO also has about 5,000 buildings connected to its fiber optic network.


Many organizations are looking for complex, multiple location, secure and reliable WANs that support the convergence of multiple services – including voice, video, and data. Some of these organizations are multinationals and need to connect locations across continents and need seamless connectivity across national borders and oceans. The use of dark fiber or wavelength solutions for these scenarios would be too costly or too complex to implement.

In MPLS VPN, a virtual private network is designed over a carrier’s private MPLS network instead of the public Internet.

MPLS (Multi-Protocol Label Switching) is a Layer 2.5 networking technology that was designed to speed up and to better shape traffic flow. In the OSI (Open Systems Interconnection) model, Layer 2 (data link layer) covers communication protocols such as Ethernet and SONET/SDH which can carry packets over simple local area networks or point to point WANs. Layer 3 (network layer) addresses the routing of IP packets across the entire network. MPLS lies somewhere in between and has additional features to transport data across an entire meshed network.

In traditional IP networks, each router does a lookup in the routing table to determine where next to send a packet. The next router repeats the process and send the packet to the next router until the packet reaches its final destination.

MPLS, on the other hand, uses label switching. The first MPLS compatible router checks the routing table for the packet final destination instead of the next router. It then determines the best route to the final destination and applies a label to the packet based on this information. Subsequent routers along the path do not have to lookup the address of the next router. This significantly improves the efficiency of the process. At the final destination, the label is removed and the packet is delivered using regular IP routing.

MPLS assigns different labels to packets with particular characteristics – hence “multilabeling”.  This  enables the network to treat packets differently according to QoS, latency and other unique requirements. For example, packets carrying real time traffic such as voice and video can be channeled along low latency routes. This is not easily achievable using traditional IP routing.

MPLS technology facilitates traffic engineering where all traffic configuration is handled at the headend.

While MPLS-VPN continues to play a significant role in enterprise wide area networks, the main criticism is that the cost of MPLS is high relative to other emerging solutions.  IT managers should therefore carefully evaluate other solutions before settling for MPLS. Alternative solutions include carrier Ethernet and SDN-WAN over public Internet.

Case Study: Regus Network Expansion

Regus is the world’s largest provider of workspace solutions with over 3,000 business centers in about 900 cities spanning across 120 countries.

Regus needed to upgrade its network connecting 400 business centers in the USA. The network had to be redundant, flexible, and highly scalable for Regus to increase connectivity speed whenever necessary.

Level 3 connected the Regus business center with an MPLS VPN delivering 100Mbps to each business center.

Carrier Ethernet

Ethernet is one of the most mature network technologies initially developed for local area networks. When first ratified by the IEEE 802.3 working group in 1983, Ethernet supported a maximum theoretical data rate of 10Mbps but it has now evolved to 100G Ethernet. The ratification of 400Gbps standard is expected in 2017 and work is in progress to develop Tbps capable Ethernet technology.

With almost every computer, enterprise building and residences equipped with Ethernet ports, the economies of scale mandates that the Ethernet cost per port has gone down. It only makes sense that the industry has extended the adoption of Ethernet in the wide area network to take advantage of the broad market reach.

The Metro Ethernet Forum (MEF) has defined carrier Ethernet as “an ubiquitous, standardized, carrier-class service and Network  defined by five attributes that distinguish it from familiar LAN based Ethernet”. The five attributes that distinguish carrier Ethernet from native Ethernet are standardization, scalability, reliability, quality of service and service management.

Carrier Ethernet standardization

The MEF defined the following two standard services for the delivery of services to the end user:

  1. E-LINE is a point-to-point Ethernet virtual connection between two user locations in a provider’s network. An E-Line can either be provisioned as an Ethernet Private Line (EPL) – a physical connection offering transparency and independency to the customer – or an Ethernet Virtual Private Line (EVPL)
  2. E-LAN is a multipoint-to-multipoint Ethernet virtual connection that enables customers to connect multiple locations together.

Carrier Ethernet scalability

The most compelling reason for migrating to carrier Ethernet is the ability to easily upgrade bandwidth when requirements change. Ethernet can be provisioned from as little as 1Mbps to as high as 100Gbps and can be upgraded in small increments.

Carrier Ethernet reliability

Additional safeguards were implemented in carrier Ethernet to improve service reliability and reduced downtime. When failures do happen, recovery should take place in less than 50ms.

Carrier Ethernet quality of service (QoS)

Carrier Ethernet comes with QoS requirements that enable advanced service level agreements (SLAs). As with MPLS, a customer can request different SLAs for difference services delivered over the same carrier Ethernet network.

Carrier Ethernet service mmanagement

Carrier Ethernet comes with the ability to monitor, diagnose, and manage the network from a central location using standards-based vendor neutral software.

Unlike native Ethernet that is implemented over short distances, carrier Ethernet can be implemented over other transport network technologies so that it can be delivered in metropolitan area networks or global wide area networks. These implementations include Ethernet over fiber, Ethernet over SONET/SDH, Ethernet over MPLS, Ethernet over OTN, Ethernet over WDM and Ethernet over µWave.

Metro Ethernet is a very attractive wide area network option for most enterprises with budget constraints or wishing to scale their WAN bandwidth in small steps. The main shortcoming for carrier Ethernet is that it is not yet as widely available as MPLS.


A hybrid WAN combines two or more wide area networks to connect geographically dispersed locations. As IT managers face increased demands for bandwidth, simply adding MPLS bandwidth can be a very costly proposition. The solution is to augment MPLS with less expensive connectivity such as the public Internet and 4G/LTE.  Sensitive traffic or traffic requiring QoS can be routed over the private MPLS network while the rest of the of the traffic is transmitted over the less expensive options.

Hybrid WAN is usually associated with, but is not identical to software defined network WAN (SD-WAN). SD-WAN is an extension of software defined networking (SDN) and is used to automate the management of wide area networks.  SDN is a network management approach that separates the control plane (the logic deciding how to handle traffic) from the data plane which forwards the traffic.

The SDN controllers manage the WAN access solutions such as MPLS, DSL, 4G, private lines or even satellite broadband. SDN decides on the access resource to send traffic depending on the requirements of the traffic at any given point in time. Critical applications such as VoIP and video conferencing will be given higher priority over the best performing paths. This way, SDN is creating service classes to prioritize traffic in a way that is not possible over the public Internet, thereby improving QoS.

SD-WAN also comes with security that makes wide area networking over the Internet significantly more secure. There is an ongoing debate on whether or not enterprises should abandon the relatively costly MPLS networks and migrate completely to SD-WAN using the inexpensive public Internet. While many have taken full advantage of the SD-WAN innovation, most enterprises still insist on using private network paths at least for the most sensitive of their traffic.

Finding Suitable Wide Area Network Solutions|Fiberguide Consulting Services

The continuous growth of information and communication services is putting tremendous amount of pressure on IT managers to connect geographically dispersed locations with ever increasing amounts of bandwidth. Emerging trends also require high quality, reliable, resilient, low latency, and highly secure connectivity solutions. In response, many national and global carriers, service providers and telecommunication vendors are continuously rolling out multitudes of innovative solutions to meet the insatiable demand for bandwidth.

Fiberguide offers consulting services to help you maneuver through hundreds of carriers and wide area network solution providers and their services. We will collect details of your technical requirements, locations and any pertinent details and match them against offerings from carriers and  vendors in our network. We use an extensive database of fiber maps and a tool that identifies carriers with fiber into any building in the USA. Our datacenter mapping software matches your  data center colocation requirements with providers.

Because we are carrier neutral, we provide the most suitable proposals and quotations from one or more providers. If you have any questions on wide area networks or you need a proposal or a quotation, please complete the form on our wide area network solutions page.

Selected wide area network references

MPLS Design Guide

MPLS explained

Benefits of MPLS

What is carrier grade Ethernet

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