# Basic concept of TCP-Vegas

TCP Vegas is a variation of the Transmission Control Protocol (TCP) congestion control algorithm that aims to improve network performance by more accurately detecting and responding to network congestion.

In standard TCP, the sender uses the number of packets that have been acknowledged by the receiver (the "congestion window") to control the rate at which it sends data. If the congestion window is large, the sender can send data more quickly, and if the congestion window is small, the sender sends data more slowly. However, this approach can be prone to errors, because the sender may not always accurately detect when the network is congested.

TCP Vegas addresses this problem by using end-to-end measurements of the round-trip time (RTT) and the actual throughput of the connection to more accurately detect and respond to network congestion. The sender uses these measurements to estimate the actual capacity of the network, and adjusts the congestion window accordingly.

In TCP Vegas, the sender also continuously monitors the RTT of the packets. If the RTT becomes too large (which is usually an indication of network congestion), the sender reduces the congestion window to slow down the rate of data transmission.

In addition to improving performance in congested networks, TCP Vegas also provides more stable and fair sharing of network resources in comparison with the traditional TCP algorithms like Reno, NewReno and Tahoe.

It should be noted that TCP Vegas is not a widely used standard and the majority of traffic on the internet still uses traditional TCP congestion control algorithms like Reno or CUBIC

## How important TCP Vegas

TCP Vegas is not widely used in production networks, and the majority of traffic on the internet still uses traditional TCP congestion control algorithms such as Reno or CUBIC.

That being said, the principles behind TCP Vegas are still considered important in the field of computer networks and have influenced the development of other congestion control algorithms. The idea of using end-to-end measurements to more accurately detect and respond to network congestion has been adopted by other algorithms, such as TCP NewReno and TCP Bic.

The key improvement that TCP Vegas provides over traditional TCP congestion control algorithms is its ability to more accurately detect and respond to network congestion. This can result in more stable and fair sharing of network resources, as well as improved performance in congested networks. It also has the ability to better handle networks with high delay and high bandwidth, which is more suitable for the need of the internet that becomes more and more diverse and dynamic.

However, the deployment of TCP Vegas is limited by the lack of support in most operating systems and routers. As a result, it is not yet widely adopted in production networks. But as the internet is evolving and new technologies like 5G and IoT are emerging, there could be a need for more efficient congestion control algorithm which TCP Vegas and its successors could fit in.

## How to use TCP vegas

To use TCP Vegas, you would first need to ensure that the operating system or device you are using has support for the algorithm. Unfortunately, support for TCP Vegas is limited and it is not widely supported in commercial operating systems or networking devices.

If your operating system does support TCP Vegas, you can typically enable it by modifying the kernel configuration or by using a command-line interface. On Linux, for example, you can enable TCP Vegas by adding the following line to the /etc/sysctl.conf file −

net.ipv4.tcp_vegas_enabled = 1


Then you can use the sysctl command to apply the changes −

sudo sysctl -p


Once TCP Vegas is enabled, it will be used automatically for new TCP connections. You can check that TCP Vegas is being used by running the sysctl command and looking for the value of the "tcp_congestion_control" variable −

sudo sysctl net.ipv4.tcp_congestion_control


It should return "vegas" if it is enabled.

It's worth to note that again, TCP Vegas is not widely supported and the majority of traffic on the internet still uses traditional TCP congestion control algorithms like Reno or CUBIC. Therefore it may not be a straightforward process to enable TCP Vegas and test it in a live network.

"Additionally, if you are planning to test TCP Vegas in a lab, keep in mind that it is a very sensitive algorithm and needs a well-controlled environment in order to show a notable improvement over other TCP algorithms.