Algorithm 2 Procedure to release a packet.

if $C_{exp}==S_1$        $O_{buf}\leftarrow S_1$        for $1<i\le M$ in parallel           $P_{i-1}\leftarrow P_i$; $P_M\leftarrow (INF,INF)$    ▹ Shift $P_2$ to $P_M$ to the left; Mark $S_M$ unoccupied           $C_{exp}++$                                                             ▹ Increment expected in-sequence counter