# Effective IoT Congestion Control Algorithm
## 2 Related Work  
Congestion control policy is generally concerned with how congestion is dealt with. It can be categorized into the following groups:  
Loss-based CCA is a type of CCA where packet loss is used as a congestion indication signal to trigger further action. TCP NewReno does not perform well in a high bandwidth-delay product (BDP) because there is sufficient bandwidth to occupy; this is not what happens in these protocols. In 2004, [PERSON] et al. [7] proposed TCP Binary Increase Congestion (BIC) control, which can deal with fast long-distance networks. This algorithm uses a binary search algorithm to identify the optimal CWND. The aggressive nature of this algorithm causes losses to increase in the network; it is therefore not intended for low-speed networks. Delay-based CCA means that any increase in delay is counted as an increase in network congestion and vice versa. Numerous protocols under this policy have been encountered. TCP Vegas [8] suggests a better Round-Trip Time (RTT) estimation than Reno estimation. As a result, it increases the general throughput; however, TCP Vegas is not suitable for high-speed networks. Hybrid CCA means that the adjustment of CWND is controlled by both Delay and Packet Loss. One of the most well-known algorithms that uses both factors to adjust the congestion window is a standard algorithm: TCP Compound [9]. It is used by Windows 7 and later. Using the same approach, TCP-FIT [10] hybrid strategies are used to control CWND. AIMD has been used to alter the CW regardless of whether there have been losses or acknowledgements. Increasing throughput is accomplished by parallel protocol operation. TCP Illinois [11] is a hybrid protocol developed for networks with high bandwidth. It alters the standard AIMD algorithms so that the modification of window size is dependent on loss and the direction is determined by delay, or more specifically RTT. It employs the default settings for the FR and the retransmission features of regular TCP NewReno. The key advantages of TCP Illinois are that it is designed to handle different types of network environments, such as wireless networks, satellite links and high latency networks. It has a range of parameters that can be adjusted to optimize performance under different network conditions, making it a flexible and adaptable algorithm. While TCP Illinois offers many advantages, there are also some potential disadvantages to consider; it may be more aggressive than other CCAs, which can lead to increased packet loss. This may occur in high-speed networks, or in networks with high packet loss rates. Also, it may not be compatible with all types of networks and may not work well with other CCAs. This can lead to interoperability issues and may require additional configuration to ensure proper functioning. TCP Illinois may not perform well in certain network conditions, such as networks with high latency or jitter; this can affect its ability to accurately measure network congestion and adjust its sending rate [12]. TCP YeAH [13] is another high-speed Hybrid CCA TCP variant. This algorithm has two modes of operation, one of which is identical to TCP Reno. The other makes use of STCP's [14] aggressive behavior. It is a CCA that is designed to improve TCP performance in high-speed and high-latency networks. While TCP YeAH is a standalone algorithm, it does incorporate elements of the NewReno and STCP congestion control mechanisms. It incorporates the fast recovery mechanism from NewReno, allowing it to quickly recover from packet loss and maintain high throughput. Specifically, when TCP YeAH detects that a packet has been lost, it enters a fast recovery phase. During this phase, it reduces the congestion window (CWND) size by half and retransmits the lost packet. This helps to prevent congestion collapse and maintain efficient network performance. It also incorporates the adaptive window sizing algorithm from STCP, which allows it to dynamically adjust the CWND size based on network conditions.