[e2e] ResiliencyToward Packet Misordering

Cottrell, Les cottrell at SLAC.Stanford.EDU
Wed Jul 31 20:54:42 PDT 2002

For each host in turn: 
1. We sent 5 56 bytes pings separated by 1 second to each host. This was to prime caches etc. We looked to see whether any of these pings were successful. If not we noted it and went on to the following host (i.e. we skipped steps 2 and 3 below). 
2. We then sent 50 back to back 56 byte pings using the preload option of the NIKHEF ping and analyzed the response to extract and record the minimum/average/maximum response time, the loss, the inter packet separation, the number of packets out of order (a packet was considered out of order if its sequence number was less than the previous successfully received packet) and any pathologies such as duplicate packets. 
3. Step 2 was then repeated for 50 56 byte ping packets sent with a separation of 1 second and a timeout of 20 seconds. 
We repeated the measurements with 1400 byte packets. 

-----Original Message-----
From: Vern Paxson [mailto:vern at icir.org]
Sent: Wednesday, July 31, 2002 6:55 PM
To: Cottrell, Les
Cc: 'Craig Partridge'; tvpoh at essex.ac.uk; end2end-interest at postel.org
Subject: Re: [e2e] ResiliencyToward Packet Misordering

> Roughly 25% of the hosts monitored exhibit reordering ...

What was the spacing between the packets you sent, and how many did you
send?  A key point with reordering is that the rate is a function of
interpacket spacing.


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