topic Re: What does source quench received mean in Operating System - HP-UX

What does source quench received mean

Sritharan — Thu, 09 May 2002 14:19:08 GMT

Hi
while I was ping ing the server I saw a message came out
Reply from *.*.*.* : source quench received

what does this mean ??
how to overcome this problem ??
check out the attachment also
thanks

Re: What does source quench received mean

MANOJ SRIVASTAVA — Thu, 09 May 2002 14:21:50 GMT

Hi Sritharan

Here it goes:

This problem has been identified and is addressed in SR 5003435396.
This problem will be fixed in the 11.01 version of the HP-UX operating
system. These messages can be safely ignored as they have absolutely no
impact on the operating system (performance or otherwise). Alternatively
these messages can be prevented by disabling source quench. For more
information see the sections below.

What is causing these messages?

At 11.0 the Streams Xport layer now passes the ICMP echo request to any
other process that has a socket open and bound to raw IP. The rpcd
rpcd/dced deamon opens a raw socket to listen to ICMP messages. This raw
socket is open by icmp_monitor routine of rpcd. The main function of
this routine is to check for error messages from DCE servers registered
in endpoint database of the host and it checks the socket every 5
minutes. It does not respond to or use the ICMP echo requests; however,
the socket queue becomes filled during the 5-minute delay causing the
source quench message. The fix being implemented in 11.01 will be to
increase the buffer size to 128 K and shorten the wait interval from 5
minutes to 2 minutes, thereby flushing the queue of these unwanted
messages before the queue becomes filled.

Why is it safe to ignore these messages or to turn them off?

A good disscussion of this is in TCPIP Illustrated Volume 1,
by Richard Stevens, pages 160-162.Here is an excerpt from page 161:

Although RFC 1009 [Braden and Postal 1987] requires a
router to generate source quenches when it runs out of
buffers, the new router requirements RFC [Almquist 1993]
changes this and says that a router must not originate
source quench errors. The current feeling is to deprecate
the source quench error, since it consumes network bandwidth
and is an ineffective and unfair fix for congestion.

Also, see RFC 1812, section 4.3.3.3 Source Quench for a good
discussion of the issues.

Also RFC 2001 has discussion on Congestion and why TCP should handle
this not ICMP:

Congestion avoidance and slow start are independent
algorithms with different objectives. But when congestion
occurs, TCP must slow down its transmission rate of packets
into the network and then invoke slow start to get things
going again. In practice, they are implemented together.

Exactly how do I disable source quench?

You can disable source quench in HP-UX 11.0 by executing this command:

ndd -set /dev/ip ip_send_source_quench 0

To disable Source Quench so that it can survive a reboot,

modify the /etc/rc.config.d/nddconf file as follows :
TRANSPORT_NAME[X]=ip
NDD_NAME[X]=ip_send_source_quench
NDD_VALUE[X]=0

Where X is the next logical numerical sequence in a table
of values, with X starting at 0.
--------------------------------------------------

DCE patch and dependencies:

3 PHCO_23651 fsck_vxfs(1M) cumulative patch
2 PHCO_23876 cumulative SAM/ObAM patch
1 PHCO_25883 cumulative 10.20 libc compatibility support
3 PHKL_18543 PM/VM/UFS/async/scsi/io/DMAPI/JFS/perf patch
3 PHKL_20016 2nd CPU not recognized in G70/H70/I70
3 PHKL_23956 Profile, virtual timers and disabling fix
3 PHKL_24027 VxFS 3.1 cumulative patch
1 PHKL_25906 Probe,IDDS,PM,VM,PA-8700,asyncio,T600,FS
1 PHKL_25999 syscall, msem_lock, umask cumulative patch
2 PHSS_21614 HP DCE/9000 1.7 Runtime cumulative patch

You may like to do like this
ndd -set /dev/ip ip_send_source_quench 0

this is solve the issue.

Manoj Srivastava

Re: What does source quench received mean

Sukant Naik — Thu, 09 May 2002 14:24:26 GMT

Hi Sritharan,

This is to do with the TCP buffers getting full.

You can avoid by doing the following

# cd /etc/rc.config.d
# vi nddconf

and add the following lines

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

-Sukant

Re: What does source quench received mean

Sachin Patel — Thu, 09 May 2002 14:25:05 GMT

run search on source quench on forum and you will receiced many many thread to explain it and how to disable it etc....

Here is sort explanation

This message is result of ping only. It is just a warning message that ICMP request that source has received is too fast and it is not able to response back. so it tells ping server to slow down. This will help to prevent their buffer from overflowing. As we can see from following figure it send this warning message only when network traffic is very very high. As you can see on second figure it starts working when you have less network traffic.

We can suppress this message very easily. And it will even improve our performance because we are getting rid of that traffic from network. Only problem is when ICMP request fails it will don't know when to stop. We can disable this error message on fly.
# ndd -set /dev/ip ip_send_source_quench 0

Re: What does source quench received mean

Deshpande Prashant — Thu, 09 May 2002 14:25:11 GMT

Hi

Check the following link.

http://us-support.external.hp.com/cki/bin/doc.pl/sid=a2ca98890d53fafb25/screen=ckiDisplayDocument?docId=200000049809940

Thanks.
Prashant Deshpande.

Re: What does source quench received mean

Sukant Naik — Thu, 09 May 2002 14:31:22 GMT

Hi Sritharan,

Here are few docs

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0xa8a7e7613948d5118fef0090279cd0f9,00.html

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0xa041af48a9e5d5118ff40090279cd0f9,00.html

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0xea6837f45ef7d4118fef0090279cd0f9,00.html

-Sukant

Re: What does source quench received mean

Sritharan — Fri, 10 May 2002 02:40:54 GMT

Hi,
I have inserted this command in the /etc/rc.config.d/nddconf
but there is no changes

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

do I have to reboot the server ??
or what else I can do to overcome to this problem.

Thanks

Re: What does source quench received mean

Vijeesh CTK — Fri, 10 May 2002 02:52:15 GMT

hi sritharan

u have to use this command

ndd -set /dev/ip ip_send_source_quench 0

this will solve ur problem

aftre reboot also u have to do the same thing as told above.for eradicating that it is told u to put th entry in nddconf file

CTK

Re: What does source quench received mean

T G Manikandan — Fri, 10 May 2002 04:54:20 GMT

Hello,
Disable the messages using

#ndd -set /dev/ip ip_send_source_quench 0
check it using
#ndd -get /dev/ip ip_send_source_quench

If you want the entries permanent
you have to make the entries in nddconf file(you have already done it).

Now the messages are stopped by using the ndd commandline option.So there is no need to reboot the server.If only there is a purpose of reboot the entries in the nddconf file will take care.

Else if you want to test it
then
YOu should do a
/sbin/init.d/net stop
/sbin/init.d/net start
OR
you should reboot your server

Thanks

Re: What does source quench received mean

Sritharan — Sat, 11 May 2002 09:31:01 GMT

Hi,

Thank you to everybody who had helped me

Thanks
Sri