[e2e] Packet reordering in Internet

Jasleen Kaur jasleen at cs.unc.edu
Wed Aug 12 07:37:33 PDT 2009

Manish and others,

We've done recent work analyzing out-of-sequence segments (due to 
reordering as well as losses) in TCP transfers. The two papers below 
describe our methodology and the results from running it on traces of 
about 3 million TCP transfers. We'd welcome feedback.

S. Rewaskar, J. Kaur, and F.D. Smith, "A Performance Study of Loss 
Detection/Recovery in Real-world TCP Implementations", in Proceedings of 
the IEEE International Conference on Network Protocols (ICNP'07), 
Beijing, China, Oct 2007.

S. Rewaskar, J. Kaur, and F.D. Smith, "A Passive State-Machine Approach 
for Accurate Analysis of TCP Out-of-Sequence Segments", in ACM Computer 
Communications Review (CCR), July 2006.


Lloyd Wood wrote:
> http://personal.ee.surrey.ac.uk/Personal/L.Wood/publications/index.html#effects-on-tcp 
> 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.
> http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094820.shtml 
> L.
> 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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