[c-nsp] ASR1006 Upgrade

Sigurbjörn Birkir Lárusson sigurbjornl at vodafone.is
Wed Jan 14 08:26:12 EST 2015

On 14/01/15 12:32, "Mark Tinka" <mark.tinka at seacom.mu> wrote:

>On Wednesday, January 14, 2015 02:06:28 PM Chuck Church
>> It depends on how long your maintenance window is.
>> Reloading the whole chassis is vastly easier, but you'll
>> be down about 5 minutes I'm guessing. ISSU is much less.
>It's not uncommon to inflate a maintenance window to account
>for some unforeseen eventuality.

Always, I'd never do a software upgrade without a maintenance window, even
if the elusive zero-packet loss is promised, that's just standard Murphy

>>  Also, if you've never done ISSU, and you've got a
>> maintenance window with a lot of time, this might be the
>> time to try the ISSU just to see how it's done, and what
>> to look out for.  There are lots of tricks and gotchas.
>> Easier to learn something when you're not under pressure
>> to have something fixed with minimal downtime.
>Ummh - lab?

If you have the equipment, that's best.  I've found that in recent
versions of code, and when you're doing a minor upgrade (say going from
15.4(2)S to 15.4(3)S) the downtime is pretty minimal

Make sure your protocols are in NSF mode:

For MPLS on the router in config mode
mpls ldp graceful-restart
Under the BGP configuration
bgp graceful-restart
Under the OSPF process,
nsf cisco
IS-IS is NSF aware by default

This will shorten the downtime due to the ISSU switch quite a bit and
enable a far more painless experience when switching RSPs as well if you
have redundant RSPs.

Also be aware that if an FPD upgrade is necessary for the software update,
that the ISSU will take place, and then the FPD upgrade will commence,
taking down the interface cards which need to be upgraded, which will
obviously cause downtime, best way to check whether that is needed is to
perform the upgrade in a lab before performing it in the field.  This
takes 15-30 seconds for each card so that will obviously impact your total
downtime (this would obviously happen with a normal upgrade as well).

Kind regards,

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