Re: [Linuxptp-devel] mcast_bind patch

[Robert C. <rob...@oc...>]

> Can you justify why we should *always* want this? perhaps there's
> reason to want a different subnet.

This patch was the minimal, localized change required to address a
problem we were seeing in our PTP application. Where an interface had
multiple IP addresses, this change made source address selection
deterministic, rather than random. Random didn't work.

> We already force the specific interface via its index, so this only
> helps in the case where there are multiple subnets on the same
> interface..

Correct. Multiple IP subnets on a single physical interface isn't an 
unusual networking configuration.

> Would it make better sense to allow a configuration option to specify
> which subet?

Maybe. Maybe not. We needed ptp4l to be consistent. Adding a
configuration item would have taken considerably more time and effort to 
implement. Adding a configuration option is design consideration. The 
patch I've provided is one possible solution to the problem we encountered.

Best regards,

Bob Carter