RE: Whats so difficult about ISSU

["Frank Bulk" <frnkblk () iname com>]

Our softswitch vendor talks about control plane bandwidths for geo-redundant
configurations on the low end of your numbers.  I'd have to drag out the
slide deck to see exactly what they recommended.

 

My point is that carrier-class products have demonstrated it's possible.

 

Frank

 

From: Tim Jackson [mailto:jackson.tim () gmail com] 
Sent: Monday, November 12, 2012 9:36 AM
To: Kasper Adel
Cc: Frank Bulk; NANOG list
Subject: Re: Whats so difficult about ISSU

 

I would argue no.

The Class 5 softswitches that are around now are off-the-shelf cPCI or ACTA
hardware running Linux or some other *nix. The TDM -> IP cards are the only
sticky point there to be upgraded, but since everything is a mid-plane, you
can do rolling N:1 upgrades across the cards with minimal (sub 400msec)
impact. There's not a ton special secret sauce there.. 

To the other point, they probably process way more than 2mbps/s of control
traffic during busy hour, especially in geo-redundant configurations as lots
of things have to be synchronized. I think you're talking more on the order
of 50-120mbps..

Yet all of this works pretty damn well.

--
Tim

 

On Mon, Nov 12, 2012 at 12:21 AM, Kasper Adel <karim.adel () gmail com> wrote:

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 () 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