On 10/28/08 13:32, Darren Reed wrote: > On 10/28/08 04:22, Kacheong Poon wrote: > >> Darren Reed wrote: >> >> >>> Correction: in theory this should only impact UDP traffic, >>> in practice it affects UDP *and* TCP traffic. >>> >> Why in theory fragmentation should only impact UDP >> traffic? What is in the protocol spec which says >> that there cannot be TCP fragments? In theory, it >> can happen with any traffic... >> >> In practice, I think most fragments in the Internet >> are UDP traffic, such as streaming media data. At >> least this is what the study I've read some years ago >> indicates (*). For this kind of app, I believe it is >> the response from server which is being fragmented. >> And I guess to load balance this type of traffic, a >> DSR set up is appropriate and the fragment issue does >> not matter. >> >> The above study is old and I don't know if there is >> any recent one. But given that nowadays most, if >> not all, client TCP stacks in use support PMTUd, I >> suspect that TCP fragments should be even rarer than >> the data in the above study shows. Do you have data >> showing that the above is no longer true in today's >> Internet? >> > > There is the continued feedback from ipfilter users that > harass me when fragmentation things don't work. The > problem isn't that "most fragments on the internet are UDP", > it is the small percentage of TCP packets that are, which > when not handled correctly, cause lots of noise. > > > Darren > > I think we are getting away from the question which is handling of fragments critical for Phase 1 of ILB project. During identifying of critical features for ILB Phase 1, this one was not raised as a "must have" item. So I would like to find out whether this is considered to be a must have item for other protocols or not.
The simplest way to handle fragmentation may be to set up a load balancing rule so that all fragments are to be handled by a specific back-end server. But I am still not convinced if handling of fragments is critical for Phase 1 of ILB project. Can folks with experience with load balancers provide some input? Sangeeta -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.opensolaris.org/pipermail/ilb-dev/attachments/20081028/8f7fd788/attachment.html>
