[Ardour-Dev] Banking on a surface

Len Ovens len at ovenwerks.net
Fri Jun 24 14:10:40 PDT 2016

On Fri, 24 Jun 2016, Melanie Bernkopf wrote:

> Sorry but with some mentions you are not right.
> default full ethernet is 1518 = 1514 ethernet2 header +4 bytes checksum
> GRE tunnel MTU is 1476 = 1500 - (20 bytes IP header + 4 bytes GRE Header) (
> similar to ADSL in Europe)
> MPLS 1492 if not configured


Sorry for not being more precise. However, in this case we are not looking 
at MTU but minimum packet size which is still generally bigger than any 
OSC message we send (except maybe /select/comment "s" "long string"). Even 
if I bundle all messages used to "zero" a strip that is not used or before 
repopulating, I suspect the data size (before headers and OSC over head) 
is less than 500 bytes. (400ish it seems)

> I would not want to send something as OSC over the inet so we stay with the
> normal ethernet2 spec on a local Network ;)

No, the mention of Inet was just that most systems configure themselves to 
work with Inet. So far as I know AoIP limits packet size too, even on GB, 
10G etc. networks. But that doesn't matter for OSC as we are dealing with 
it. We are not sending "blobs", but bundles could easily put two messages 
in one minimum sized packet. In this case the second message goes free.

Anyway, bundling is worth while. And it appears there is no danger of 
making a too big packet. Speed itself (on the lan) is not Ardour's problem 
but a system setup and hardware issue.

Len Ovens

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