Re: TCP limitations (was Re: ISCSI: Urgent Flag requirementviolates TCP.)

["Randall R. Stewart" <randall@stewart.chicago.il.us>]

Ronald:

Comments below...


ronald lee wrote:
> 
> I was wondering, is it possible to use TCP option field to
> do the framing.  This will require a change to TCP protocol
> to handle this option,
> but for implementations that want to get the higher performance
> they can make this change, else stick with what is there.
> Just a suggestion.
> 

I believe this is clearly OUTSIDE the scope of the WG. We CANNOT
change TCP.. period... if you desire to do this, you must take
this to the end2end group (as Scott suggested)...


> Also, is defragging IP packets any issue with iSCSI hardware
> implementations ?  We at MaxStrat did a hardware to accelerate
> TCP/IP over HIPPI and I had to deal with fragmented IP packets which
> caused
> a change in the hardware architecture.  Buffer management is a
> big issue when trying to accelerate TCP/IP with hardware.  What
> happens if a fragment is missing and lets say many IP packets
> have a missing fragment or fragments that arrives late.  We might
> get our buffers filled with fragments.

Hmm, seems to me if you implement P-MTU discovery this problem would
go away, but I do agree that if there is no P-MTU discovery you may
have a problem with fragments....


R

> 
> -- ron

-- 
Randall R. Stewart
randall@stewart.chicago.il.us or rrs@cisco.com
815-342-5222 (cell) 815-477-2127 (work)