How to Quicken TCP Re-transmission?

[mag at intron.ac]

     I believe two points:

1. Receiver should tell sender to re-send as soon as possible.
   (But TCP makes receiver purely passive)
2. Receiver should tell sender what is really necessary to re-send.
   (Sometimes only a single ACK number of TCP cannot include enough
    information)
------------------------------------------------------------------------
                                                From Beijing, China

Mark Allman wrote:

> 
>> You can take a look at SCPS - http://www.scps.org/ Their protocol is
>> used on lossy links with big latency and packet loss (such as
>> satellites) and overcomes shortcomings of TCP.  It works with divert
>> mechanism of FreeBSD and I ported the tap device part as well to both
>> NetBSD / FreeBSD (experimental).
> 
> It's not clear to me that this is going to help.  Fundamentally, TCP and
> SCTP share the same congestion control response.  At 30% packet loss
> SCTP ought to be as unusable as TCP.  Both consider losses to be
> indications of network congestion.
> 
> SCTP does have some things built-in that need to be added onto TCP
> (e.g., SACK).  So, we could expect more consistent behavior from SCTP
> across implementations and platforms.  But, in the end the performance
> of both is proportional to 1/sqrt(p) where p is the loss rate.  So, as
> the loss rate increases performance decreases.  At 30% you're
> essentially cooked no matter which you use.
> 
> allman
> 
> 
>