  Standard congestion control cannot detect link failure losses which occur due
to mobility and power scarcity in multi-hop Ad-Hoc network (MANET). Moreover,
successive executions of Back-off algorithm deficiently grow Retransmission
Timeout (RTO) exponentially for new route. The importance of detecting and
responding link failure losses is to prevent sender from remaining idle
unnecessarily and manage number of packet retransmission overhead. In contrast
to Cross-layer approaches which require feedback information from lower layers,
this paper operates purely in Transport layer. This paper explores an
end-to-end threshold-based algorithm which enhances congestion control to
address link failure loss in MANET. It consists of two phases. First,
threshold-based loss classification algorithm distinguishes losses due to link
failure by estimating queue usage based on Relative One-way Trip Time (ROTT).
Second phase adjusts RTO for new route by comparing capabilities of new route
to the broken route using available information in Transport layer such as ROTT
and number of hops.
