Showing results for 
Search instead for 
Did you mean: 

6500 sup720 code upgrade justification

Level 1
Level 1

We are taking the network offline this weekend to do software upgrades on almost all of our equipment.  But my manager does not want to take off-line our 6506-E VSS core because he thinks we don't need to. 

We are currently running version 15.1(2)SY7 and i would like to move to the gold/recommended version of 12.1(2)SY10.  He feels that because it has been running for a year on that code we are fine.  We are not doing any fancy stuff simple routing etc.  I can't find any "show stopping" or real concerns that i feel need to be changed except that is the recommended version.

I have looked at the CVE's and used the Cisco IOS software checker.  Can't really find anything.  So does any one have any suggestions, like is that version ok.  Why should we upgrade etc?

Thanks from a basic engineer.

5 Replies 5

Reza Sharifi
Hall of Fame
Hall of Fame

I agree with your manger. The version you are running is not very old and since it has been solid and you don't need any other features, why change it. The problem with upgrade is that it may fix one thing but break couple of other things that you happen to use today.  

Good Luck



Sorry, I just type slower than you but at least we said the same thing :)


Hi Jon,

Not sure if I am any faster than you but as you said, we think alike :)



Jon Marshall
Hall of Fame
Hall of Fame

You will get different answers from different people on here.

My personal take is unless you have a bug that is affecting you or there is a new feature you need that is not supported in your current IOS then I would not upgrade because I cannot see the point especially as the current IOS is meeting all your requirements.

In other words if it isn't broke don't fix it.

But there are others on here who always upgrade to the latest stable IOS so perhaps any of them could add their thought to this.


Joseph W. Doherty
Hall of Fame
Hall of Fame

Why should we upgrade etc?

Jon well answered that with ". . . you have a bug that is affecting you or there is a new feature you need that is not supported in your current IOS . . . "

That said, although there's much merit in ". . . if it isn't broke don't fix it.", I think it's often not properly considered.  Generally, every maintenance/patch release is fixing something.  I.e SY7 is broke compared to SY10.  However, what's "broke" might not, and often isn't, applicable to your usage.  Further, as Reza notes, maintenance/patch releases sometimes introduce new bugs, which may impact you.

So, when there's no clear cut bug you've bumped into, or no new feature need, you need to weigh whether a later IOS version is really better, for you, then the chance of it being worst for you.  This can be a very difficult decision, and not easy to make.  Many try to play safe by avoiding any new updates unless they think they really, really need to make them.  (Speaking of sayings, this is along the lines of "better with the devil you know vs. the one you don't - laugh)

Personally, if you were SY1 or SY2, the value of jumping to SY10 would likely be more important than jumping from SY7, as most of a release's issues are usually found early on.

Also personally, I tend to advocate for planned upgrades, even when strictly not needed.  This doesn't though mean rushing into every new release the moment you can, just that, discounting feature bloat, vendors sometimes actually improve their software, doing whatever it's already has been doing without much fanfare that it has been, in fact, improved.

When such a policy is used, I seen some issues never become issues because we're already past the older problem versions.  Conversely, though, as Reza warns, I have seen new IOS versions introduce issues that didn't exist before.  (Besides not rushing into every latest release, a planned software upgrade policy should also allow for lots of testing and device subset upgrades.)

In this specific case, I too would likely agree with your manager, Jon and Reza, that upgrading from SY7 to SY10 isn't probably warranted without a more specific need. Yet, once or twice year, you might review your software versions, and redetermine if a software upgrade is warranted.

Review Cisco Networking for a $25 gift card