SSH is not a shell, but a secure channel that provides different services over this channel (tunnel), including shell, file transfer, or X11 forwarding.
DPI-SSH supports both route mode and Wire Mode. For Wire Mode, DPI-SSH is only supported in the secure (active DPI of inline traffic) mode. For route mode, there is no limitation.
SSH supports different client and server implementations, as listed in Supported Clients/Servers.
DPI-SSH supports up to 250 connections.