Re: [Xen-users] intermittent network hangs

["John Madden" <jmadden@xxxxxxxxxxx>]

> John, are you seeing tcp retransmits, at least?

No, although I'm no expert when it comes to tcpdump.  Here's the relevant 
snippet
of the sniff from the domU:

10:07:34.826810 IP 10.0.15.67 > helpdesk.ivytech.edu: icmp 64: echo request seq 
194
10:07:35.157683 IP 10.0.15.67.26034 > helpdesk.ivytech.edu.ssh: P 
27984:28032(48)
ack 164033 win 15376 <nop,nop,timestamp 331977649 25997694>
10:07:35.158475 IP 10.0.15.67.26034 > helpdesk.ivytech.edu.ssh: . ack 164753 win
15376 <nop,nop,timestamp 331977650 25997769>
10:07:39.784691 IP 10.0.15.67.26034 > helpdesk.ivytech.edu.ssh: P 
28032:28080(48)
ack 164753 win 15376 <nop,nop,timestamp 331978253 25997769>
10:07:39.784707 IP 10.0.15.67 > helpdesk.ivytech.edu: icmp 64: echo request seq 
195
10:07:39.784728 IP 10.0.15.67.26034 > helpdesk.ivytech.edu.ssh: P 
28032:28080(48)
ack 164753 win 15376 <nop,nop,timestamp 331978454 25997769>
10:07:39.785085 IP 10.0.15.67.26034 > helpdesk.ivytech.edu.ssh: P 
28080:28320(240)
ack 164753 win 15376 <nop,nop,timestamp 331982277 25998232>
10:07:39.786365 IP 10.0.15.67.26034 > helpdesk.ivytech.edu.ssh: . ack 164817 win
15376 <nop,nop,timestamp 331982278 25998232>
10:07:39.786411 IP 10.0.15.67.26034 > helpdesk.ivytech.edu.ssh: . ack 164929 win
15376 <nop,nop,timestamp 331982278 25998232>
10:07:39.826972 IP 10.0.15.67 > helpdesk.ivytech.edu: icmp 64: echo request seq 
199
10:07:40.827022 IP 10.0.15.67 > helpdesk.ivytech.edu: icmp 64: echo request seq 
200
10:07:41.827073 IP 10.0.15.67 > helpdesk.ivytech.edu: icmp 64: echo request seq 
201

Basically, I was running the tcpdump from domU (helpdesk.ivytech.edu) and ssh'd
into it and pinging it from 10.0.15.67.  The dump shows the missing icmp echo's
for seq's 196, 197, and 198, during which time there was no response to ssh
traffic either (although it eventually catches up, but that's likely 
ssh-specific
behavior anyway, not tcp retrans).

John



-- 
John Madden
UNIX Systems Engineer
Ivy Tech Community College of Indiana
jmadden@xxxxxxxxxxx


_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users