What Is Network Bandwidth?

Network bandwidth is the maximum theoretical rate of data transfer over a network segment or connection. Network bandwidth is measured by the amount of data that can be transmitted in a time period, for example, 10 Gbps. Actual network speeds never meet the total network bandwidth, due to factors such as shared bandwidth and network traffic. There are various ways to get the highest speeds from your network bandwidth, such as using a dedicated network, routing strategies, and compression.

A network’s bandwidth is measured in units of bits per second (bps), commonly as megabits per second (Mbps) or gigabits per second (Gbps). However, measuring bandwidth speed alone typically does not provide sufficient context for assessing real-world network performance. Actual performance is best evaluated in conjunction with other metrics, such as throughput and latency.

Throughput

Throughput measures the actual amount of data successfully transmitted across a network within a given timeframe. In real-world environments, throughput is typically lower than the upper limit defined by bandwidth, due to network congestion, packet loss, or hardware limitations. For example, on a 1 Gbps fiber line, throughput might only reach 700 Mbps. Measuring throughput against bandwidth can help provide context for the efficiency of your network.

Latency

Latency is the time it takes for data to travel across a network. Networks with high latency, or “lag”, have a longer delay from sending to receiving. Those with fast response times have low latency. Latency is typically measured in milliseconds (ms). High-bandwidth connections can still deliver sub-standard user experiences if latency is high, for example, in real-time applications such as video conferencing, gaming, or securities trading.

Using bandwidth monitoring tools

Monitoring bandwidth, throughput, and latency together can provide a much stronger, contextual understanding of network performance than any one metric alone. You can use a number of network monitoring tools to track these metrics and the services that impact them in your environments.

For example, in the AWS cloud, Amazon CloudWatch collects real-time metrics such as inbound and outbound network activity across your AWS resources. You can set alerts to notify you when utilization reaches specific thresholds. Amazon Virtual Private Cloud (Amazon VPC) Flow Logs capture information about IP traffic flowing in and out of a VPC. AWS CloudTrail and AWS Config can log API activity and configuration changes.

Bandwidth represents the maximum theoretical transmission rate of a network. Many real-world factors can prevent your network from performing near that maximum rate. Recognizing and addressing these constraints on network performance helps you maintain optimal network performance.

Network technology limitations

The physical or virtual medium you use to transmit data plays a major role in bandwidth utilization. For example, legacy copper networks typically have lower maximum bandwidth and are more susceptible to electromagnetic interference (EMI), which can degrade signals, compared to more modern networks, such as fiber. Older and newer Wi-Fi standards, such as 802.11ac and 802.11ax (Wi-Fi 6), offer vastly different levels of performance.

In cloud environments, the choice of instance type and its associated network performance directly impacts the maximum achievable bandwidth. For example, your performance may change if your Amazon EC2 instance is configured for multi-flow or single-flow traffic, and the number of vCPUs allocated.

Network congestion

Congestion can occur when a high volume of users, network devices, or applications simultaneously use a single network or internet connection. This can be a common occurrence during peak bandwidth usage times. Congested network traffic can lead to lower network throughput, increased latency, and packet loss.

For example, many users performing large file transfers simultaneously might compete for bandwidth with real-time applications such as video conferencing. If the network is not configured to prioritize one job type over another, file transfers slow down, and video conferencing might stutter or freeze.

Protocol overhead

For network protocols to function, they must add header data that can also reduce effective bandwidth. For example, the widely used transmission control protocol (TCP) helps ensure reliable delivery of data, uses acknowledgments, retransmissions, and flow control mechanisms. Each of those mechanisms consumes additional processing time and bandwidth for each packet sent over a network. Security protocols, such as Transport Layer Security (TLS), encrypt data but also increase packet size and require more computational resources, which can lead to increased latency and reduced throughput.

Network infrastructure limitations

How you configure routers, switches, firewalls, and load balancers can impact the reliability of network traffic flow. Older or underpowered hardware can create bottlenecks, especially as demand grows over time. In hybrid cloud environments, limitations in on-premises infrastructure, such as if you do not have sufficient bandwidth in your outbound internet connection, can restrict performance even when you have adequate cloud-side capacity.

You can structure networks to use bandwidth in several different ways.

Symmetric bandwidth

Symmetric bandwidth connections provide equal upload and download speeds. They are best for applications requiring consistent network performance in both directions—for example, video conferencing, real-time collaboration software, remote server hosting, and cloud backup operations. High-performance connections such as fiber optic lines typically offer symmetric bandwidth.

Asymmetric bandwidth

Asymmetric bandwidth connections have unequal upload and download speeds, typically with faster downloads than uploads. They are well-suited for environments where users consume more data than they send and are commonly used for Internet bandwidth, in residential broadband, and many business internet plans.

Dedicated bandwidth

Dedicated bandwidth connections are reserved exclusively for a single organization to provide maximum capacity and predictable performance. Because they are not shared with other users or organizations, they can help prevent congestion and lag, making them well-suited for applications such as financial transactions and high-priority video conferencing.

Shared bandwidth

Shared bandwidth is distributed across multiple devices and users on the same network infrastructure. Many internet service providers and standard cloud connections use this model. Although more affordable, performance can fluctuate during peak usage times due to congestion.

Network bandwidth optimization is the process of maximizing network efficiency and maintaining throughput as close to the theoretical maximum bandwidth as possible. Many different resources are available to optimize cloud network bandwidth.

Use dedicated network connections

Public internet connections are often not the best choice for running critical workloads. Dedicated network connections bypass the public internet and associated congestion and jitter.

For example, AWS Direct Connect provides a private link between your on-premises infrastructure and AWS. It is suitable for hybrid cloud operations and tasks such as data replication.

Help optimize bandwidth with traffic routing

Traffic routing schemes, mechanisms, and tools can help optimize bandwidth in congested networks.

For example, AWS Transit Gateway is a centralized, scalable router that can connect your Amazon VPCs and on-premises networks. Instead of managing complex architectures and relationships, you establish each connection once to the Transit Gateway, where you can more effectively optimize routing.

Segment networks for better control

Applying network segmentation can help you isolate high-bandwidth or sensitive workloads from general traffic.

For example, Amazon Virtual Private Clouds (Amazon VPCs) use security groups that help you limit lateral movement during security events and give you more granular control over traffic flow.

Apply data compression before data transfer

Compressing data by reducing its size before transmission helps conserve bandwidth and speed up delivery. Compression works especially well for text-based content such as HTML pages, JSON files, and logs. Newer protocols, such as HTTP/2 or gRPC, support header compression and multiplexing, which can also help improve overall network efficiency.

Use caching and content delivery networks (CDNs)

You can help reduce redundant data transfers by caching content closer to end users.

For example, Amazon CloudFront, AWS’s content delivery network (CDN), stores copies of frequently-accessed content at network edge locations around the world. Using a CDN helps reduce overall communication with your central origin servers.

AWS offers a range of networking solutions that help you get the fastest speeds to and within your cloud resources. Placing cloud resources within the same region and availability zone is a quick start, and edge solutions offer a least-distance path to your network. Other AWS services that help with bandwidth optimization include:

• AWS Direct Connect is the shortest path from your internal network to your AWS resources. While in transit, your network traffic remains on the AWS global network and never touches the public internet. This reduces the chance of hitting bottlenecks or unexpected increases in latency.

• AWS Transit Gateway connects your Amazon Virtual Private Clouds (VPCs) and on-premises networks through a central hub. This connection simplifies your network and puts an end to complex peering relationships. Transit Gateway acts as a highly scalable cloud router—each new connection is made only once.

• Amazon Virtual Private Cloud (Amazon VPC) gives you full control over your virtual networking environment, including resource placement, connectivity, and security. Using Amazon VPC, you can create an optimized cloud network environment for your organization.

Get started with solutions to optimize your network bandwidth on AWS by creating a free account today.