The SameSide class represents traffic in which the source and the destination IP address attributes of a flow are determined to both be on the ‘inside?of a PacketShaper device by checking the hostdb entries.
For an example as to how this might occur, consider the following configuration:
Subnet_1|-----PacketShaper --- Router ----WAN
In this example, traffic from Subnet_1 intended towards Subnet_2 would travel through the PacketShaper device to the router, and then be directed by the router back again through the PacketShaper device to Subnet_2. Since this flow never crosses the WAN link, it is placed into a separate class and bandwidth that hits that class is not considered when shaping network traffic.
Another possible reason the SameSide class might auto-discover is if the Inside and Outside Ethernet cables were switched. NOTE: If that is the case, the PacketShaper may need to be reset (to flush the hostdb entries) in order to reliably manage network flows that might be mis-identified as SameSide traffic.
If you see discrepancy in SameSide classification, you can delete the auto created SameSide class, change the sys set autoCreateSameSide to 0 and then manually create a class that matches LAN to LAN traffic and put an 'ignore' policy.