Whats so difficult about ISSU

Mon Nov 12 06:21:32 UTC 2012

Hi Frank,

Is it because C5 softswitches have expensive hardware, advanced software
and dual asics? I would have never imagined that any vendor is capable of
upgrading fpd's/ASICs ucode without a hit unless there are multiple chips
continuously syncing with each other.

Regards,
Kim

On Monday, November 12, 2012, Frank Bulk wrote:

> We do it on our Class 5 softswitch ... and it works consistently.  There
> may
> be a few seconds, once, where a new call can't be made, but most people
> will
> re-dial.  It just works.
>
> It can be done, but the product has to be built with that in mind.
>
> Frank
>
> -----Original Message-----
> From: Kasper Adel [mailto:karim.adel at gmail.com <javascript:;>]
> Sent: Thursday, November 08, 2012 5:23 PM
> To: NANOG list
> Subject: Whats so difficult about ISSU
>
> 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
>
>
>