[e2e] Packet reordering in Internet

Alexander Afanasyev alexander.afanasyev at ucla.edu
Tue Aug 11 15:57:32 PDT 2009

Hi Manish,

You can check some recent papers. For example, Arthur et. al "Keeping Order:
Determining the Effect of TCP Packet Reordering" (2007) and Arkko et al.
"Dagstuhl perspectives workshop on end-to-end protocols for the future

They say that indeed load balancing and parallelism (physical,
channel, or network
layer) will be (if not already is) dominated cause of packet
reordering in the Internet.

Reordering also can be caused by AQM (active queue management) or by various
DiffServ implementations. In wireless networks, channel level retransmission may
have significant impact on reordering. Theoretically, reroutings
(e.g., route flapping)
also can cause some kind of reordering. However, there was a lot of
work to prevent
flapping and enforce same routing for the single flows.

In fact, today TCP has some basic mechanism to mitigate reordering
effect. Have you
checked the Eifel algorithm (RFC4015 - the Eifel response algorithm for TCP)?


On Tue, Aug 11, 2009 at 2:57 PM, Manish Jain<jain.manish at gmail.com> wrote:
> 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

More information about the end2end-interest mailing list