Source Quench Received

[Alexander Santamaria Ji]

When i run a ping to one of the network
interfases, received the message:

Source Quench Received

How can i correct this situation?

Is there some potential network or interfase problem?

Best Regards

Alexander Santamaria

[John Poff]

Hi,

It isn't a big problem. You are seeing that message because the ICMP protocol is busy for that interface, and it is a way for it to do some flow control and politely say, "Leave me alone, I'm busy.". It is a old protocol, and you can turn it off using the 'ndd' command in HP-UX 11.X. Just try this:

ndd -get /dev/ip ip_send_source_quench

If it returns a 1, you have source quench turned on. You can do this:

ndd -set /dev/ip ip_send_source_quench 0

to turn it off. That setting will last until you reboot. If you want to keep the change, you'll have to put it in the in /etc/rc.config.d/nddconf file.


JP

[James R. Ferguson]

Hi:

Generally this represents a full-buffer condition. The sender should slow the rate of delivery to the socket in question. Have a look at Technical Knowledge Base document #S3100005739 for more information.

Regards!

...JRF...

[Berlene Herren]

RFC792 has a good description:

http://www.faqs.org/rfcs/rfc792.html

Berlene

[Alexander Santamaria Ji]

Hi;

Thanks for your responses

I can't find the S3100005739 document if
somebody has it can you send to me as an
attachment

Best Regards

Alexander Santamaria

[Michael Tully]

Hi,

I had not trouble finding it. Instead of searching for the document number use 'source quench'

HTH
Michael


PROBLEM
Upon pinging an 11.0 system, I am seeing a packet loss and Internet
Control Message Protocol (ICMP) source quench messages.

Why am I getting these messages?


CONFIGURATION
Operating System - HP-UX
Version - 11.0
Subsystem - Internet Control Message Protocol (ICMP)

RESOLUTION
ICMP source quench messages are generated when an IP packet is
received by the 11.0 system that can't be delivered to the socket
buffer of the receiving application. The intent is to inform the
sender of the full buffer condition so the rate of the transmission
is slowed down until the buffer can be read by the receiving
application.

Setting the ndd parameter ip_send_source_quench to 0 can be an
effective way to deal with the messages.

Programs that use icmp protocol, such as ping, use a type of
socket called SOCK_RAW. The nature of using raw IP sockets is
that ALL packets received that match the protocol type of the raw
socket are delivered to ALL the sockets using that protocol. It is
up to the application to read all the data in it's socket buffer
and discard the data it's not interested in. If any of these
sockets are full, the icmp source quench message will be generated.

One process that uses one of these sockets is part of DCE, and it
is 'rpcd'. This program opens a raw socket in order to listen for
icmp messages, which it uses to monitor the health of other systems
on the network running DCE. In this case 'rpcd' used a 32K buffer,
and processed the messages received every 5 minutes, which led to
the buffer full condition.

PHSS_17810 addresses the problem by increasing
the buffer size to 128K and processing the messages every 2 minutes.

[Ron Kinner]

We had this problem over a year ago. After I posted a question on the forum I got back the above article and the information that you could turn it off in ndd. I forwarded the info to my HPUX admin group and they elected to just just try the ndd change since this was a production system and they are afraid of breaking something. (Also a patch would have to be done at 3AM during our only downtime window and they don't like to stay up all night to do it.) We have been running happily with the ndd change now for over a year with no adverse effects. Just don't forget to change the /etc/rc.config.d/nddconf file so that if it reboots you will still have it.

TRANSPORT_NAME[0]=ip
NDD_NAME[0]=ip_send_source_quench
NDD_VALUE[0]=0

(Increase the number in brackets to the next unused integer if you already have entries in this file.)

Ron