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Whats so difficult about ISSU
On 11/11/12, Miquel van Smoorenburg <mikevs at xs4all.net> wrote:
> Which isn't really a problem, none of the control plane stuff needs
> to run in the kernel. The only thing that needs to run in the
> kernel is the device driver(s) to talk to the forwarding plane
Yes. But avoiding kernel mode is a consideration, even before GPL.
Perhaps GPL is just another force to discourage developers from doing what
they shouldn't be doing anyways -- which is to insert complicated code in the
kernel itself to do application-specific things, instead of
providing hardware interfaces
You introduce risks if you run control plane things in kernel mode
ring0 and not separate control plane functions into user processes.
Risks that buggy code will be executed with privilege and corrupt
Risks that a buffer overflow in the SNMP code will crash the kernel
and cause the entire control unit to reboot.
If instead, each control function is a separate user process, running without
privilege in protected mode, then you have a larger amount of fault isolation
provided by the hardware -- restart the SNMP process automatically,
but leave ISISd/Bgpd alone, and no kernel panic...
> hardware, but if you use ethernet or infiniband for that
> communication you don't need any proprietary drivers.