Re: [Bloat] Random idea in reaction to all the discussion of TCPflavours - timestamps?

[david@lang.hm]

On Mon, 21 Mar 2011, Jonathan Morton wrote:

> On 21 Mar, 2011, at 12:18 am, david@lang.hm wrote:
>
>>> 0) Buffering more than 1 second of data is always unacceptable.
>>
>> what about satellite links? my understanding is that the four round 
>> trips to geosync orbit (request up, down, reply up down) result in 
>> approximatly 1 sec round trip.
>
> That is true, but it doesn't require more than a full second of 
> buffering, just lots of FEC to avoid packet loss on the link.  At those 
> timescales, you want the flow to look smooth, not bursty.  Bursty is 
> normal at 100ms timescales.
>
> What I've heard is that most consumer satellite links use split-TCP 
> anyway (proxy boxes at each end) thus relieving the Internet at large 
> from coping with an unusual problem.  However, it also seems likely that 
> backbone satellite links exist which do not use this technique.  I heard 
> something about South America, maybe?

I've heard that they do proxy boxes at each end for common protocols like 
HTTP, but they can't do so for other protocols (think ssh for example)

> Anyway, with a 1-second RTT, the formula comes out to max 1 second of 
> buffering because of the clamping.

and what if you have a 1 second satellite link plus 'normal internet 
latency', or worse, both ends are on a satellite link, giving you a 
2-second+ round trip time?

if you don't have large enough buffers to handle this, what happens?

David Lang