ICMP Source Quench messages
ICMP Source Quench message is used to inform the source computer to reduce the rate of IPv4 datagram packets that the source sends. When the source is sending too many IPv4 datagram packets that receiving host cannot process it, it will send an ICMP Source Quench message back to the sender. The source computer can then slow down the rate of sending IPv4 datagram packets, until the source stop receiving ICMP Source Quench messages. ICMP Source Quench message is not much used these days and it is deprecated.
ICMP Source Quench message Type number is 4. Please click next link to know more about Type and Code fields in ICMP header