[157797] in North American Network Operators' Group
Re: Whats so difficult about ISSU
daemon@ATHENA.MIT.EDU (Phil)
Thu Nov 8 19:48:34 2012
In-Reply-To: <CALb2afM1G1KHRMWM7PE0XUYdtJscD319_LhSxBJxkCxZs3aDZg@mail.gmail.com>
From: Phil <bedard.phil@gmail.com>
Date: Thu, 8 Nov 2012 19:48:07 -0500
To: Kasper Adel <karim.adel@gmail.com>
Cc: NANOG list <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
The major vendors have figured it out for the most part by moving to statefu=
l synchronization between control plane modules and implementing non-stop ro=
uting. =20
ALU has supported ISSU on minor releases for many years and just added suppo=
rt for major releases.=20
The Cisco Nexus ISSU works well, I've done an upgrade on a 5K switch and it w=
as completely hitless.=20
Juniper and Cisco with the 9K have gone through some hurdles but ISSU is act=
ually usable now if the software versions support it. =20
The main remaining hurdle is updating microcode on linecards, they still nee=
d to be rebooted after an upgrade. =20
Phil
On Nov 8, 2012, at 6:22 PM, Kasper Adel <karim.adel@gmail.com> wrote:
> Hello,
>=20
> We've been hearing about ISSU for so many years and i didnt hear that any
> vendor was able to achieve it yet.
>=20
> What is the technical reason behind that?
>=20
> 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?
>=20
> Thanks,
> Kim
