Re: (4 bits from PID * 24 bits from @link_sat_adress) == 28 bits.

["Kearney" <clausen@cosy.sbg.ac.at>]

 From: "Ghassane Aniba" <Ghassane.Aniba@sophia.inria.fr>
Sent: Tuesday, April 23, 2002 1:19 AM
Subject: (4 bits from PID * 24 bits from @link_sat_adress) == 28 bits.


.....SNIP.
>
> If we take in consideration, that most of IP packet are 1500 or 576, and
> 40 or 48, and with a simple calcul, we see that the overhead don't
> affect.
> One thing more, i'll present another schema of encapsulation, into
> reduce the treatment on board the satellite.
>
We should not base an encapsulation design on the momentarily observed
packet statistics - as has been pointed out by several people, this might
change very quickly.
Furthermore, when we start packing - and with a 184 byte payload field this
seems advisable, then your argument

> if we use the SNDU encapsulation ( + 8 bytes for each IP packet), we
..... assume for example a FTP transfer of a file of 100KByte
>
> 152 bytes free  ----->   584 bytes (4*184 bytes)
>
 leads to the following comparison:
without packing you transmit a total of 126,592 (give or take a few) Bytes,
with packing you transfer 100,096 bytes (give or take a few, depending on
your encapsulation)
and that IS a significant difference.

if you think that is too big - take 10KB in which case the number come out
to 13,248/10,120.

--Horst


BTW I don't seem to get all your messages - from Gorrys replies I can see
that I am missing some.