Unexplained 0.1% packets time out when pinging from router
I'm troubleshooting a customer who requires the ability to send 5000 pings
from the router to their remote site over a satellite link with zero
timeouts, yet they keep experiencing one to five packets lost per test.
Under ordinary circumstances, I'd be willing to chalk up such a low loss
rate as the cost of a satellite link, but the drops only show up when
pinging from the router to the remote site. To clarify, here's the
involved network devices:
Outbound Traffic
192.1.1.51 Router Hub
192.1.1.52 TX Switch Hub
192.1.1.50 Encapsulator Hub
172.1.1.1 Remote Site Remote
Return Traffic
172.1.1.1 Remote Site Remote
192.1.1.28 Channel Unit Hub
192.1.1.53 RX Switch Hub
192.1.1.51 Router Hub
When pinging from the Router to the remote site, the losses show up. When
pinging from a Sun server attached to the TX switch (bypassing the
router), the 5000 pings complete without a single loss. This verifies the
entire satellite path, and all equipment except for the router.
Then I tried sending 5000 pings from the router to all of the other
devices aside from the remote site...and I got back all 5000 almost
instantaneously with no drops, so the connection from the router to
everything else in the path is verified good.
The router in question is a Cisco 7206VXR, and the cpu utilization doesn't
appear to ever go above 50%. The highest process is only at 20%, so I'm
not confident that it's simply a matter of the router dropping ICMP
packets due to lower priority, particularly given the router will send
5000 packets to local devices with no issues.
I also looked into the possibility of a null route, but the only possible
culprit is an essential route for remote access, according to the
customer, and I can't post their running config here to get a second
opinion.
Any suggestions would be greatly appreciated. I have very little
networking experience, and I'm beating my head against the wall to
reconcile these seemingly contradictory symptoms.
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