This can yield a variety of benefits such as fault tolerance, increased bandwidth, and improved security.
To improve performance or fault tolerance, concurrent multipath routing (CMR) is often taken to mean simultaneous management and utilization of multiple available paths for the transmission of streams of data.
However, under CMR, some applications may be slower in offering traffic to the transport layer, thus starving paths assigned to them, causing under-utilization.
Also, moving to the alternative path will incur a potentially disruptive period during which the connection is re-established.
The packets are distributed to the physical paths via some algorithm e.g. round-robin or weighted fair queuing.