Whats so difficult about ISSU

Fri Nov 9 00:52:09 UTC 2012

What i was asking is full ISSU, even with micro code. I assume between
Major release there will be microcode upgrade most of the time.

On Fri, Nov 9, 2012 at 2:48 AM, Phil <bedard.phil at gmail.com> wrote:

> The major vendors have figured it out for the most part by moving to
> stateful synchronization between control plane modules and implementing
> non-stop routing.
>
> ALU has supported ISSU on minor releases for many years and just added
> support for major releases.
>
> The Cisco Nexus ISSU works well, I've done an upgrade on a 5K switch and
> it was completely hitless.
>
> Juniper and Cisco with the 9K have gone through some hurdles but ISSU is
> actually usable now if the software versions support it.
>
> The main remaining hurdle is updating microcode on linecards, they still
> need to be rebooted after an upgrade.
>
> Phil
>
> On Nov 8, 2012, at 6:22 PM, Kasper Adel <karim.adel at gmail.com> wrote:
>
> > Hello,
> >
> > We've been hearing about ISSU for so many years and i didnt hear that any
> > vendor was able to achieve it yet.
> >
> > What is the technical reason behind that?
> >
> > If i understand correctly, the way it will be done would be simply to
> have
> > extra ASICs/HW to be able to build dual circuits accessing the same
> memory,
> > and gracefully switch from one to another. Is that right?
> >
> > Thanks,
> > Kim
>