Configuring Window Size

You can configure the maximum window size for packet processing at each end of the L2TP tunnel:

The receive window size limits the number of concurrent packets the server processes. By default, the maximum is 16 packets. To change the window size, include the receive-window statement at the [edit services l2tp tunnel-group group-name] hierarchy level:receive-window packets;
The maximum-send window size limits the other end’s receive window size. The information is transmitted in the receive window size attribute-value pair. By default, the maximum is 32 packets. To change the window size, include the maximum-send-window statement at the [edit services l2tp tunnel-group group-name] hierarchy level:maximum-send-window packets;