Why is the throughput less than the bandwidth provided by ISP?

One of the most crucial aspects of network performance is speed, which we measure using throughput and bandwidth. Administrators need this information to enhance network performance, target services, and billing information.

Bandwidth

The amount of data that can be sent and received per second is defined as bandwidth. A network can transmit more data back and forth with a larger bandwidth. The term, bandwidth, is used to measure theoretical capacity rather than the actual capacity.

Note: High bandwidth does not guarantee high network performance. Even if we have a considerable amount of available bandwidth, we'll experience delays if the network's throughput is disrupted.

Representation

The standard units to represent bandwidth are bits per second (bps), megabits10^6 bits per second (Mbps), and gigabits10^9 bits per second (Gbps).

Throughput

The rate at which messages successfully reach the destination is called throughput. Instead of being a theoretical metric of packet delivery, it is an actual indicator.

Users expect their requests to be answered quickly. Poor or delayed network performance is caused by low throughput. Depending upon the network condition it fluctuates accordingly. Throughput is a useful metric for evaluating network speed since it can pinpoint the core cause of a slow network and notify administrators of the issues in particular.

Representation

Network throughput is often expressed in bits per second (bps)It is a unit for measuring data transmission rate in one second across the network.. It can also be represented as data packets per second.

Analogy

It is not always easy to grasp how bandwidth and throughput differ. Although both are closely related and provide information on the network's data in two ways.

We may visualize data throughput as cars and bandwidth as a highway. More cars can travel through the spacious highway quickly. On the other hand, they will move slowly through the narrow road. A simple illustration portrays the concept of throughput and bandwidth as follows:

Throughput vs. bandwidth

Reasoning

Suppose the ISP claims a connection is 4Mbps. When users begin downloading/streaming something, they notice a considerably lower speed. There could be several explanations for this. The following explains the leading causes of less throughput provided by ISP:

Network congestion

There are multiple reasons responsible for network congestion:

  • The server is a bottleneck: This is the most apparent reason, as everyone knows that internet speed deteriorates during peak periods. For example, when most people are connected to the server to watch the final world cup match and thus utilize the internet. More traffic causes more network congestion, which means reduced throughput for each user.

  • The last mile link is the bottleneck: It seems that the network will be more burdened as it has to meet all these data needs at once, whether it be all the customers in a specific area or all the rooms in one house connected to the wireless router. At peak hours, the network resources and available bandwidth must be shared across many users, resulting in a decreased throughput allotted to each user.

  • Some link along the end-to-end path is the bottleneck: We usually hear that the internet is slow because the submarine cable link is damaged.

  • The noisy or fading channel also leads to reduced network performance.

  • If a user is using TCPTransmission Control Protocol and the other user uses UDPUser Datagram Protocol on the shared link. TCP's congestion control would slow the process whereas UDP communicates at maximum capacity as no congestion control mechanism is involved in UDP.

Type of traffic in a network

More data-intensive forms of internet usage will increase network congestion, resulting in reduced speed for each user.

  • Therefore, if users on a network are doing gentle browsing and checking their emails, this does not use much bandwidth. However, intensive internet activities like streaming video and movies and downloading large files use a great portion of bandwidth. If many people do this simultaneously in a particular area, internet speeds will tend to slow down significantly.

  • One good example is the emergence of the Netflix streaming service.

Network Design

In networking, this refers to the number of hopsHop is the distance traveled by a data packet in the network from one router or intermediary point to another. that data must traverse before reaching the final destination. The more devices the data pass through, such as servers, boosters, exchanges, and switches, the more likely the throughput is reduced from its ideal potential.

The reasons above explain the primary grounds of getting less throughput than bandwidth, which would ultimately result in slower network performance.

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