Discussion seems to diverge a bit from the USB support question on ASR9001, but this is an important topic. I would like to capture this under its own umbrella for those that are interested in this topic also.
ISSU is not simple. The minute one makes API changes or CLI changes ISSU is hard to maintain. When do those changes happen? based on feature requirements we get from our users... It is a delicate tradeoff between features and support, since we have reduced the reboot time from 30 mins in 42 (with 1M routes and full convergence) down to 8 minute in shipping 512 release and with a target of 5 mins in 513 I think we are minimizing the impact that reloads have on the operations.
Also having a true maintenance release eg 434 and 513 allows for much better support. ISSU is definitely doable within a specific feature set, however there are always some restrictions which we try to disclose to the best of our ability.
Nexus platforms have much less feature requirements and for that reason it is much easier to achieve there. Also we have many high availability and redundancy improvements in place such as GEO redundancy, cluster and the like to allow for near 100% up time.
It is just a very balanced trade off between meeting the demands from two different camps of requirements that are mutually exclusive. For instance the EMR (extended maintenance release) strategy gives that stability view, but prevents quick delivery of feature(ttes). For this we are implementing a feature-pack strategy (a-la service packs but with extra goodies) to serve as many people as we can.
We're not sitting still in this front :)
Will you be attending Cisco Live next week? Would love to meet you and discuss this more in detail or in some other "forum" to go into the details.
I know the competition (ALU) has a solid story in this regard, but see it working first. I generally don't discuss competitors, because I feel everyone has goods and bads and my itent is to show you the functionality we have and are planning for.
You know cisco strategy is to give an open book always, and more often then not it bites us in the butt. At the same time I hope you can see and experience that we take requirements very seriously and act on it directly.
But then again, it is always a balancing act between different views, and I always take direction from genuine and supportive users like yourself on the product we create so proudly to influence decisions and take try to make the best strategic decisions possible...
While this is not a conclusive answer I realize ,I am telling you that ISSU has a LOT of focus and many improvements are in progress to improve the overall user experience. As you're moving from 43 to 51 and beyond, I hope you'll experience it also.
cheers!
xander
