Lossy cogent p2p experiences?

Tue Sep 5 10:01:08 UTC 2023

Nick Hilliard wrote:

>> Are you saying you thought a 100G Ethernet link actually consisting
>> of 4 parallel 25G links, which is an example of "equal speed multi
>> parallel point to point links", were relying on hashing?
> 
> this is an excellent example of what we're not talking about in this 
> thread.

Not "we", but "you".

> A 100G serdes is an unbuffered mechanism which includes a PLL, and this 
> allows the style of clock/signal synchronisation required for the 
> deserialised 4x25G lanes to be reserialised at the far end.  This is one 
> of the mechanisms used for packet / cell / bit spray, and it works 
> really well.

That's why I, instead of fully shared buffer, mentioned round robin
as the proper solution for the case.

> This thread is talking about buffered transmission links on routers / 
> switches on systems which provide no clocking synchronisation and not 
> even a guarantee that the bearer circuits have comparable latencies. 
> ECMP / hash based load balancing is a crock, no doubt about it;

See the first three lines of this mail to find that I explicitly
mentioned "equal speed multi parallel point to point links" as the
context for round robin.

As I already told you:

: In theory, you can always fabricate unrealistic counter examples
: against theories by ignoring essential assumptions of the theories.

you are keep ignoring essential assumptions for no good purposes.

						Masataka Ohta