Jnettop allows administrators of routers to watch online traffic coming across the network in a fashion similar to the way top displays statistics about processes. It is useful for quickly evaluating the state of the network.
Pace-ICMP is a utility that can allow X amount of ICMP (ping, etc) packets travel to the host, once X is exceeded, all ICMP traffic is blocked. This allows ping and traceroute functionality, while still protecting you against ICMP attacks.