[LARTC] re: Anyone else seen this one? (ping)

[don-lartc@isis.cs3-inc.com (Don Cohen)]

 Anyone else seen this one?
 > 
 > ping -n {remote host}
 > { 6 second delay }
 > 64 bytes from 216.168.105.33: icmp_seq=0 ttl%5 time=6sec
 > 64 bytes from 216.168.105.33: icmp_seq=1 ttl%5 time=5sec
 > 64 bytes from 216.168.105.33: icmp_seq=2 ttl%5 time=4sec
 > 64 bytes from 216.168.105.33: icmp_seq=3 ttl%5 time=3sec
 > 64 bytes from 216.168.105.33: icmp_seq=4 ttl%5 time=2sec
 > 64 bytes from 216.168.105.33: icmp_seq=5 ttl%5 time=1sec
 > 64 bytes from 216.168.105.33: icmp_seq=6 ttl%5 time$2usec
 > 64 bytes from 216.168.105.33: icmp_seq=7 ttl%5 time%0usec
 > ...

Yes, and I know just how to make it happen.

You put ping packets and some other type of packets into the same
low rate class.  Then you send a bunch of the other kind of packet
and start your ping.  Suppose your class is allowed to send 10 pps
and you start with 60 other packets (perhaps even ping packets
belonging to someone else) in the queue when you start your ping.
6 seconds later all of your ping packets get to the head of the queue
and are sent in the next second.  Of course, the first one was sent 6
sec ago, but the next was sent 5 sec. ago, the third 4 sec. ago, etc.
The first 6 replies all return at about the same time and look like
those above.  The rest appear at 1 sec intervals as you send them
and look like the last two.

BTW, this is pretty similar to the example that lead me to suggest a
limited lifetime in the queue.

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