Bug 526478

Summary:	Win2003 PV Drivers: Network traffic loss
Product:	Red Hat Enterprise Linux 5	Reporter:	Jeff Bastian <jbastian>
Component:	xenpv-win	Assignee:	Xen Maintainance List <xen-maint>
Status:	CLOSED INSUFFICIENT_DATA	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	5.4	CC:	james.brown, pbonzini, tao
Target Milestone:	rc
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2010-09-30 12:11:26 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	518407

Description Jeff Bastian 2009-09-30 14:46:45 UTC

Description of problem:
When increasing the TCP Receive Window in the windows TCP settings, large spikes in traffic can cause complete network traffic loss in the domU with no recovery.

Version-Release number of selected component (if applicable):
xenpv-win 1.0.0
Windows 2003 32-bit and 64-bit

How reproducible:
always

Steps to Reproduce:
1. In Windows 2003 (32 bit was tested), change the default tcp
   receive window size to 256K by setting the registry value
   "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Afd\Parameters\DefaultReceiveWindow"
   to 262144.  If this value doesn't exist, create a REG_DWORD for
   'DefaultReceiveWindow'.
2. Reboot the host.
3. Connect to the domU host using Remote Desktop.
4. Start a 'ping -t' to some responsive host.
5. In another window, download a large file (>=300MB) from a relatively fast, 
   close host.

Actual results:
Very shortly after starting the download, the Remote desktop connection will be cease to be responsive.  Approximately 30-60 seconds later, it may return.  If it returns, you should also see that the local ping task has experienced timeouts as well.

Expected results:
no traffic loss

Additional info:

Comment 4 RHEL Program Management 2010-08-09 19:18:37 UTC

This request was evaluated by Red Hat Product Management for
inclusion in the current release of Red Hat Enterprise Linux.
Because the affected component is not scheduled to be updated in the
current release, Red Hat is unfortunately unable to address this
request at this time. Red Hat invites you to ask your support
representative to propose this request, if appropriate and relevant,
in the next release of Red Hat Enterprise Linux.

Comment 5 Paolo Bonzini 2010-09-30 11:50:51 UTC

James, any news on this?

Comment 6 James G. Brown III 2010-09-30 12:11:26 UTC

Paolo, I don't believe this is reproducible by the original reporter. I am closing this insufficient data for now. 

- James