Source quench received.

While ping, you may get a result like ;
Reply from xxx.xxx.xxx.xxx: Source quench received.
Reply from xxx.xxx.xxx.xxx: Source quench received.
Reply from xxx.xxx.xxx.xxx: Source quench received.
These messages can be ignored, because they have no impact on the operating system.
Possible causes are,
A single destination is affected by data from many sources,
Device’s speed variation,
When Low speed network speaks to high speed network.
Hardware Failure.
In HP-UX, this has been fixed in the 11.01 Version itself. If you want, we can disable this message by,
ndd -set /dev/ip ip_send_source_quench 0
To make it permanent, add the following lines in to /etc/rc.config.d/nddconf file
TRANSPORT_NAME[0]=ip
NDD_NAME[0]=ip_send_source_quench
NDD_VALUE[0]=0
Explanation :
The flow control mechanism in IP is the Internet Control Message Protocol (ICMP) Source Quench message. In effect, when IP packets arrive too quickly for a node to handle, it can send a Source Quench message, which essentially tells the source of the packets to back off. This message should not be considered a problem.
For detailed study,
http://www.tcpipguide.com/free/t_ICMPv4SourceQuenchMessages.htm