[e2e] packet reordering in OC 48 links

[Cannara]

The problem has been solved by some network-processor vendors for a few years
now.  For example, see the specs for the IQ2200 by Vitesse, that's been used
to handle 4 parallel, FDX 1Gb/s ports in equipment by various manufacturers,
including Cisco.

Alex

Nischal Piratla wrote:
> 
> Govind,
> We feel that it is quite reasonable to see such high amounts of reordering. In
> fact, we are working on this very problem.
> 
> Most of the reordering that occurs within the routers is countered by either
> input reordering (packets of same flow are added to same queue) or output
> reordering (packets from same flow are tagged at the input, and are collected
> to be sent in order at the output). However, due to increasing table sizes,
> difference in the rates of increase in network speeds vs. the computing
> speeds, etc., higher parallelism is inevitable and the methods stated above
> may not be useful. We discussed a little more about it in our recent paper:
> 
> http://lamar.colostate.edu/~nischal/Papers/Networking2005_RD.pdf
> 
> Also, to understand the amount and extent of reordering, we suggest 'Reorder
> Density' metric that comprehensively illustrates reordering. There are perl
> scripts and Java applets readily available for the same on this site:
> 
> http://www.cnrl.colostate.edu/packet_reorder.html
> 
> - Nischal Piratla
> 
> >===== Original Message From "S.Govind" <sgovind at hpc.serc.iisc.ernet.in> =====
> >hi all
> >
> >
> >I have currently programmed the intel IXP 2400 Network Processor for IPv4
> >forwarding.
> >Iam able to support line rates up to 3 Gbps (without any QoS provisioning)
> >but an area of concern is the reordering, i obtain reordering up to 33%
> >(ie: 33 % packets are reordered )for a link with 4000 flows a second
> >each TCP flow of size 6.4 KB and 14% reordering for flow size of 640 B.
> >
> >The packets are assumed to be arriving at a constant interval of time and
> >of constant size (64 B ), this assumption is used for DoS attacks.
> >
> >I am novice in networking, i have a few queries regarding the above
> >results.
> >
> >Are these numbers (reordering) indicative of current OC 48 links,
> >
> >
> >Any comments and/or suggestions on the above  is most welcome
> >
> >Thanking You,
> >Govind
> >
> >
> >--
> 
> /******************************************
> Research Assistant
> Computer Networking Research Laboratory
> Department of Electrical and Computer Eng.
> 1373, Colorado State University,
> Fort Collins, CO 80523 USA
> http://www.cnrl.colostate.edu
> http://lamar.colostate.edu/~nischal
> *******************************************