09-13-2009 12:25 PM - edited 03-06-2019 07:42 AM
We have a packet loss issue when pinging from a switch to another switch. We believe this packet loss issue may be the cause of a customer complaint.
In doing some testing, I see the packet loss issue, but as soon as I enable debugging, it goes away. What's going on here?
======================
Sending 50, 2000-byte ICMP Echos to 68.115.X.Y, timeout is 2 seconds:
With debugging off:
Success rate is 38 percent (19/50), round-trip min/avg/max = 16/23/48 ms
With debugging on:
Success rate is 100 percent (50/50), round-trip min/avg/max = 16/25/60 ms
09-13-2009 12:27 PM
Here's the debug we are running:
access-list 155 permit icmp any host 68.115.X.Y log
access-list 155 permit icmp host 68.115.X.Y any log
debug ip packet 155 detail
09-13-2009 02:55 PM
Please post a SH INT for the affected interface(s); a SHOW BUFFERS might be useful as well.
Packet drop / loss is usually either congestion, as seen by the transmitter, {or | which causes} queuing timeouts.
The congestion can be the receiver's inability to catch the traffic being pushed to it. This happens a lot when you have asymmetrical bandwidth (one end is a T1, the other is a 56K DDS or Frac T1, for example).
09-13-2009 04:46 PM
Debug enabled and you have zero packet loss? I smell an IOS bug. What's the IOS you are using?
09-13-2009 08:06 PM
IOS is Version 12.2(44)SG
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