Starting with Coherence 3.1 a warning will be issued if the OS allocates a smaller socket buffer then Coherence has requested. The warning will be similar to:
UnicastUdpSocket failed to set receive buffer size to 1428 packets (2096304 bytes); actual size is 89 packets (131071 bytes). Consult your OS documentation regarding increasing the maximum socket buffer size. Proceeding with the actual value may cause sub-optimal performance.
This indicates that your is OS not configured to support large network buffers, and this may degrade performance. Though it is safe to operate with small buffers it is recommended that you configure your OS to allow for larger buffers. See Datagram Test (Tuning) for details on increasing the maximum buffer size.