The default packet size for SLP is 1400 bytes. The size should be sufficient for most local area networks. For wireless networks or wide area networks, you can reduce the packet size to avoid message fragmentation and reduce network traffic. For local area networks that have larger packets, increasing the packet size can improve performance. You can determine whether the packet size needs to be reduced by checking the minimum packet size for your network. If the network medium has a smaller packet size, you can reduce the net.slp.MTU value accordingly.
You can increase the packet size if your network medium has larger packets. However, unless the service advertisements from SAs or queries from UAs frequently overflow the default packet size, you should not have to change the net.slp.MTU value. You can use snoop to determine whether UA requests often overflow the default packet size and roll over to use TCP rather than UDP.
The net.slp.MTU property measures the complete IP packet size, including the link layer header, the IP header, the UDP or TCP header, and the SLP message.