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Divacks can be used to ramp-up the
cwnd in TCP after a vertical handover.
When vertical handovers (or even horizontal handovers between networks with different levels of congestion) occur, the congestion control state of TCP may need to be adjusted. Right after the handover, the value of TCP's
cwnd is adapted to the previous network's capacity. To have feedback about the new network capacity, at least one new RTT has to elapse. It may then take several new RTTs for the congestion control state to update to the actual
cwnd the new network can support.
Considering mobile TCP receivers, it may be possible, using ACK division techniques, to ramp-up the remote server to ramp up its
cwnd and occupy the network more quickly.
More attention may need to be paid to the possibility of ramping down the
cwnd without causing too much congestion on the new network if its capacity is not as large as the previous one.