[Info-vax] DECnte over CI?

[H Vlems]

On 27 okt, 04:25, Howard S Shubs <how... at shubs.net> wrote:
> In article <ia7lhq$do... at Iltempo.Update.UU.SE>,
>  Johnny Billquist <b... at softjar.se> wrote:
>
> > Huh??? The ethernet packet size is 1500 bytes. Unless I remember wrong,
> > the packet size of CI is 8K...
>
> If the 1500b is mostly used, and the 8K is by far empty, what says that
> wrt overhead?
>
> --
> May all your good dreams and fine wishes come true! - The Wizard
> May joy be yours all the days of your life! - Phina

On ethernet the average packetsize is around a third of 1500B.
Sometimes even less.
Ethernet packets have a variable length, within bounds.
If the CI had a fixed packet size of 8 kB, not unreasonable for
disktransfers, then an average DECnet packet
would have used only 7% of the available timeslot on the CI.
Assume a flow of 500B packets on 10 Mb/s ethernet. Put that traffic on
the CI bus in 8 kB packets and in order to
achieve the same response times it ought to have been 16 times as
fast. Which the CI obviously wasn't.
Hans