Algorithm 3 Procedure to insert a new packet $U_j$ and release a packet concurrently.

Release $S_1$ to output and insert packet $U_j$ in pipeline    if $C_{exp}==S_1$ and $U_j$ arrives        Find k such that $S_i<U_s$ for $1\le i\le k-1$, and $S_i>U_s$ for $i\ge k$        $O_{buf}\leftarrow S_1$        for $1<i\le k-1$ in parallel           $P_{i-1}\leftarrow P_i$; $P_{k-1}\leftarrow U_j$                  ▹ Shift $P_2$ to $P_{k-1}$ to the left; Insert $U_j$ at $P_{k-1}$           $C_{exp}++$                                                   ▹ Increment expected in-sequence counter