  Being most popular and IETF standard metric, minimum hop count is
appropriately used by Ad hoc Networks, as new paths must rapidly be found in
the situations where quality paths could not be found in due time due to high
node mobility. There always has been a tradeoff between throughput and energy
consumption, but stationary topology of WMNs and high node density of WSN's
benefit the algorithms to consider quality-aware routing to choose the best
routes. In this paper, we analytically review ongoing research on wireless
routing metrics which are based on ETX (Expected Transmission Count) as it
performs better than minimum hop count under link availability. Performances
over ETX, target platforms and design requirements of these ETX based metrics
are high-lighted. Consequences of the criteria being adopted (in addition to
expected link layer transmissions & retransmissions) in the form of
incremental: (1) performance overheads and computational complexity causing
inefficient use of network resources and instability of the routing algorithm,
(2) throughput gains achieved with better utilization of wireless medium
resources have been elaborated.
