This paper analyzes the impact of mobility on TCP performance in mobile ad hoc networks (MANETs). TCP, the standard protocol for the Internet, is used in MANETs, but its performance is significantly affected by link failures caused by node movement. Unlike congestion, link failures are not recognized by TCP, leading to reduced throughput. The paper presents simulation results showing that TCP throughput drops sharply when nodes move, and in some cases, throughput can be zero. A new metric, expected throughput, is introduced to compare TCP performance in multi-hop networks. This metric accounts for variations in throughput based on the number of hops. The paper also explores how explicit link failure notification (ELFN) techniques can improve TCP performance by allowing TCP to distinguish between link failures and congestion. Simulation results show that ELFN significantly improves TCP performance, with throughput closer to the expected throughput line. The paper also discusses the effects of mobility on TCP performance, including route failures, stale routes, and the impact of routing protocols on TCP. It concludes that improving routing protocols to better handle mobility can enhance TCP performance in MANETs. The paper also suggests that modifications to TCP, such as using ELFN, can help TCP recognize mobility-induced delays and losses, allowing it to adjust accordingly. The study highlights the importance of routing protocols in MANETs and the need for further research into improving TCP performance in these environments.This paper analyzes the impact of mobility on TCP performance in mobile ad hoc networks (MANETs). TCP, the standard protocol for the Internet, is used in MANETs, but its performance is significantly affected by link failures caused by node movement. Unlike congestion, link failures are not recognized by TCP, leading to reduced throughput. The paper presents simulation results showing that TCP throughput drops sharply when nodes move, and in some cases, throughput can be zero. A new metric, expected throughput, is introduced to compare TCP performance in multi-hop networks. This metric accounts for variations in throughput based on the number of hops. The paper also explores how explicit link failure notification (ELFN) techniques can improve TCP performance by allowing TCP to distinguish between link failures and congestion. Simulation results show that ELFN significantly improves TCP performance, with throughput closer to the expected throughput line. The paper also discusses the effects of mobility on TCP performance, including route failures, stale routes, and the impact of routing protocols on TCP. It concludes that improving routing protocols to better handle mobility can enhance TCP performance in MANETs. The paper also suggests that modifications to TCP, such as using ELFN, can help TCP recognize mobility-induced delays and losses, allowing it to adjust accordingly. The study highlights the importance of routing protocols in MANETs and the need for further research into improving TCP performance in these environments.