Whats so difficult about ISSU

Mon Nov 12 04:13:19 UTC 2012

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] 
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