There are many factors that were responsible for the performance degradation of TCP over MANETS and few of them are as listed below 

Bit Error Rates: High Bit Error rates are always responsible for the performance evaluation of TCP across MANETs. In general wireless routes are heavily porn to high bit error rates due to some internal reasons like signal degradation and multipath fading and thus finally leads to packet losses and TCP data segment losses. Now the TCP will unnecessarily invoke the congestion control mechanism and thus the overall system performance is affected a lot. 

Route Failures: There could many chances of route failures across MANETS due to its mobility and thus it simply affects the performance of TCP. In general the route reestablishment time taken by the MANETs depends on the routing protocol used across them and in some cases it would take more time and now the TCP would in a congestion state and initiates the congestion control mechanism, as a result the overall system performance is affected. 

Multipath routing: Multipath routing is the basic characteristic of MANETs and also one of the important factors responsible for performance degradation of TCP over mobile Adhoc networks. In general multiple routes are maintained across the sender and receiver and thus results in out-of-sequence packets at the receiver. Due to this duplicate ACKs are generated across the network and this scenarios is similar to a congestion situation across TCP and thus again the TCP would invoke the congestion control mechanism to reduce the duplicates.

This paper is written and submitted by Sujana Priya V