If network saturation is occuring quickly (saturation at less than 8CPUs for an application server running on a 100mbit Ethernet), then an investigation to ensure conservative network usage is a good first step.
Increase network bandwidth. Steps that possibly can be taken: upgrade to a switched network, more network interfaces are a possible solution or upgrade to a higher bandwidth network to accommodate your network traffic demand.
netstat —sP tcp options are used to analyze the TCP kernel module. Many of the fields reported represent fields in the kernel module that indicate bottlenecks. These bottlenecks can be addressed using the ndd command and the tuning parameters.