[e2e] Packet reordering in Internet

Lloyd Wood L.Wood at surrey.ac.uk
Tue Aug 11 19:55:35 PDT 2009

Lloyd Wood, George Pavlou and Barry Evans, 'Effects on TCP of routing  
strategies in satellite constellations', IEEE Communications Magazine,  
vol. 39, no. 3, pp. 172-181, March 2001.

digs into how TCP's dupack, fast retransmit and recovery, and delack  
behaviour work when exposed to a rather artificial strawman round- 
robin per-packet multipath mesh environment, and shows that SACK is a  
very good idea. This used ns simulation with distance vector router  
and multipath enabled. (it's described in more detail in Ch. 4 of my  
PhD thesis.)

Load balancing in real routers generally defaults to per-destination  
IP address, which is sufficient to prevent reordering of flows. See e.g.

On 12 Aug 2009, at 00:09, Craig Partridge wrote:

> I don't think anyone's replicated the experiment that Bennett,  
> Shectman
> and I did back in 1999 ("Packet Reordering is Not Pathological Network
> Behavior" in IEEE/ACM TON, Dec 1999).  I could be wrong.
> Thanks!
> Craig
>> Hello,
>> I was wondering if there are measurement studies of Internet traffic
>> quantifying the magnitude of packet reordering within a TCP flow. Is
>> reordering a common problem for TCP in the current Internet? How  
>> about
>> the load balancing features in the routers from major vendors : is it
>> per flow basis or per packet basis, and if flow based load balancing
>> is done, then how is the flow classification is done these routers?
>> What could be/are other sources of reordering withing a TCP flow?
>> Thanks,
>> Manish
> ********************
> Craig Partridge
> Chief Scientist, BBN Technologies
> E-mail: craig at aland.bbn.com or craig at bbn.com
> Phone: +1 517 324 3425

DTN work: http://info.ee.surrey.ac.uk/Personal/L.Wood/saratoga/

<http://info.surrey.ac.uk/Personal/L.Wood/><L.Wood at surrey.ac.uk>

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