Backhaul links the main networks to the smaller edge networks, enabling users to access the internet.
What you’re about to read:
- Backhaul refers to the system of copper, fiber, or wireless connections that bridge the main (backbone) networks with the edge subnetworks, allowing users to access the internet by reaching the subnetwork first.
- It’s objective is to increase network coverage
- In this post we’ll explain the meaning, how it works, and practical applications of backhaul
What is Backhaul
The term “backhaul” is commonly used in the context of wireless internet access. Essentially, a backhaul enhances the speed of data communications. Without it, there would be no internet connection for users. The backhaul connection refers to the flow of data from the wireless cell site to the internet.
In a telecom network with a hierarchical structure, the backhaul component encompasses all of the intermediary links that connect the central (backbone) network to the smaller subnetworks at the network’s edge.
As a result, the commonly accepted definition of backhaul in both commercial and technical circles is the part of the network responsible for connecting to the global internet. This is achieved by acquiring wholesale access to a core network access site, such as an internet exchange point.
Middle-mile networks may exist between the client’s local area network (LAN) and the exchange points, which can be a wide area network (WAN) link. Both the internet service provider (ISP) and high-speed internet are connected to the middle-mile infrastructure, which acts as an intermediary between the two.
While backhauls can technically be used in any network, they are most commonly deployed in mobile networks. Backhauls are used to transfer data between base stations and mobile devices. Connecting a cell tower to the network infrastructure is the task of the mobile network’s backhaul, also known as mobile backhaul. The two primary methods for accomplishing this are fiber-based backhaul and wireless point-to-point backhaul.
With the increasing demands for capacity and lower latency in 4G LTE and 5G networks, many older technologies are being phased out. This includes technologies such as point-to-multipoint wireless, copper-based wireline, and satellite communications, which are no longer widely used for backhauls.
What Backhaul Looks Like
The basic function of any data network, including the public internet, is to route information from one end (such as a cell phone) to the other (such as a website) and back. However, this is not a simple task. The function is carried out by several different network segments:
(1) The access network is responsible for connecting endpoint devices to the network.
(2) The primary network is in charge of distributing data to secondary networks.
(3) The backhaul network acts as a bridge between the core network infrastructure and the access network, as well as vice versa.
In this context, backhaul refers to the connection between access nodes and the core network.
A local subnetwork is comprised of a group of mobile phones that can communicate with a specific cell tower. The backhaul connection to the backbone of the ISP’s network acts as the starting point for the connection that extends from the cell site to the wider world (through an intersection point).
This backhaul connection can include copper cables, fiber optics, or wireless components, depending on the situation. One might encounter microwave bands, mesh network topologies, or edge network architectures within the wireless segments. The backhaul may also use a high-capacity wireless channel to transfer data packets from the cell tower to the microwave or fiber connections.
The planning of a backhaul network considers various criteria, the most crucial of which are the desired data transfer rate (often referred to as bandwidth) and the time it takes for data to travel from one location to another (known as latency). The backhaul impacts interruption, reliability, flexibility, and speed, all of which are traffic requirements that have a significant impact on the end-user experience.
4 Types of Backhaul
There are a few notable types of backhaul, some of which can be further classified into different subcategories.
The majority of backhaul activities are performed over wired connections, primarily fiber-optic networks, but also over legacy copper-based T-1 lines in some cases. Fiber-optic systems are preferred over copper for transmitting voice, video, and data traffic due to their advantages in terms of speed, latency, and capacity. A deeper examination of its subtypes will further elaborate on this concept.
Copper-based Backhaul: At one point, copper-based backhaul was the primary technology used for 2G and 3G backhaul. The T1/E1 protocol, which allowed for data transfer rates of 1.5 Mbps to 2 Mbps, was at the core of this type of backhaul. However, it has since been replaced by fiber for the most part. Dark
Fiber Backhaul: This is a valuable resource for wireless network carriers, allowing them to establish their own services and operate custom-fitted networks. For example, dark fiber is rented out to wireless carriers in the form of specialized fiber pairs, typically containing two to twelve fibers. The wireless carriers then activate the fiber using their own optoelectronics.
Ethernet Backhaul: Ethernet backhaul is a fiber-based transport service that allows wireless carriers to expand the coverage of their networks by securing the final connection. Ethernet circuits with backhaul are available for sale with large amounts of available bandwidth, fully managed by network service companies. This type of backhaul is mainly used by businesses.
In wireless backhaul or fixed wireless backhaul, audio, video, and data traffic are transmitted through microwave connections enabled by the wireless spectrum. Wireless carriers often install a microwave dish on top of a cell tower to facilitate the backhaul process. The point-to-point data transmission is carried out using a specific type of antenna known as a microwave dish.
Wireless backhaul that relies on microwave technology primarily targets rural, isolated, and remote locations where there is less demand for bandwidth. This is because microwave technology is unable to meet the data traffic requirements in highly populated urban and suburban areas.
For the transmission of audio, video, and data, wireless backhaul makes use of licensed wireless spectrum, particularly millimeter wave (mmWave) bands.
In remote or hard-to-reach areas, such as rural regions, satellite backhaul is used by mobile network operators (MNOs) as a niche solution or as a temporary backup plan. This type of backhaul provides support in the event of an emergency or while waiting for the approval of a microwave link license.
Satellite backhaul is also used in both developed and developing markets as a complementary technology. It has a downlink capacity of 150 Mbps and an uplink capacity of 10 Mbps. However, it has a drawback in terms of latency, with a round-trip delay of about 500-600 milliseconds for a geostationary satellite.
Wi-Fi backhaul leverages tiny cells to extend a wireless carrier’s network to its periphery. This is achieved by placing a small cell, also known as a femtocell, in a customer’s home to provide both indoor and outdoor wireless connection services.
Wi-Fi backhaul provides a different connection option for customers located outside their homes, allowing for wireless services to be delivered in areas not covered by the wireless provider. Instead of relying on a connection to a cell tower, Wi-Fi backhaul uses the wired Ethernet backhaul provided by the customer’s gateway device, also known as an access point. These remotely deployable access points not only serve as transportation nodes, but also provide cellular connection services at the network’s edges.
As a result, Wi-Fi backhaul enables wireless carriers to cost-effectively increase network density while enhancing coverage and capacity. It is a solution that can be used in places where conventional dark fiber or microwave connections are either unavailable or too expensive to implement.
Backhaul Customers, Who are They?
The customers of backhaul are primarily mobile network operators (MNOs) and telecommunications companies. These companies use backhaul to connect their cell towers and base stations to the larger network infrastructure. This enables them to provide wireless voice and data services to their customers.
In some cases, large enterprises and government organizations may also be customers of backhaul services, especially in instances where they need to connect remote locations to the main network infrastructure.
Additionally, fixed wireless service providers and internet service providers (ISPs) may also use backhaul to connect their access points to the main network.
Vital Applications of Backhaul
- Widening Public Connectivity in Metropolitan Area Networks: Metropolitan Area Networks (MANs), also known as “Wi-Fi nets”, are used by cities to provide widespread high-bandwidth connectivity throughout an area. Users or subscribers can access the network even if they don’t have cabling installed at their homes or workplaces, as the wireless backhaul allows for reliable connections in public spaces like parks, streets, and shops.
- Enhancing Operational Security: Organizations can improve the security of their operations with the help of backhauls. For instance, monitoring networks keep a watchful eye on criminal activity, but if the connection drops, it may miss a crucial moment. Wireless backhaul can reinforce this link and provide last-mile aggregation, allowing for a direct connection to the internet, eliminating the need for intermediaries. The wireless network can transmit thousands of data channels and efficiently handle data, video, and voice traffic.
- Supporting 5G Expansion: The most significant use of wireless backhaul is to support the growth of 5G. The 5G backhaul architecture, which can be wired, fiber-optic, or wireless, presents numerous opportunities to expand and enhance broadband access for wireless carriers and their clients, as well as for private corporations working with 5G networks, in both the public and private sectors.
- Addressing Mobile Networking Challenges: There are several changes in the network that will pose new challenges for wireless carriers and mobile virtual network operators (MVNOs). These include the need for 100 times more capacity and the management of 5G network densification. Backhauls provide a solution to these issues, being crucial in the deployment of new cell sites that offer increased capacity, lower latency, and the ability to manage various services.
- Strengthening Private Networks: Private networks are increasingly becoming the preferred method for providing broadband access to the industrial IoT environment, corporate campuses, and other institutional settings. There is a high demand for capacity from enterprise applications, multimedia traffic, and intra- and inter-organizational communications. Backhaul, also known as transmission networks, is a crucial component of the private network architecture.
- Modernizing Critical Infrastructure: Critical infrastructure consumers have stringent requirements and need their connections to be both accessible and secure at all times. Examples of critical communications users include public health and safety services, utilities, transportation companies, and other specialists. The existing mission-critical networks are based on specialized digital technologies, which makes them voice-centric and limited in bandwidth. However, the critical infrastructure sector is undergoing rapid change, with many public safety organizations exploring 4G and 5G technologies that require backhauls to function properly. Public safety broadband networks like FirstNet in the United States, Emergency Services Network (ESN) in the UK, and SafeNet in the Korean Republic, are some of the first examples globally. Backhaul remains the most important component in constructing these mission-critical computer networks.
Backhaul operates behind the scenes, playing a crucial role in shaping internet experiences, particularly on mobile networks and devices. With the transition from 4G to 5G and eventually 6G, last-mile connectivity has become increasingly critical, making it imperative for organizations to have a solid understanding and proper utilization of backhaul. Despite being largely unnoticed by end users, backhaul is a crucial component in ensuring seamless internet experiences.
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