[c-nsp] Cisco 7201 -- Differences between the 12."2" images and the usual 12.4/15 images?

[Gert Doering]

Hi,

On Mon, Mar 08, 2010 at 09:32:54AM -0600, P C wrote:
> I'm deploying a Cisco 7200 series router.  I've used ISRs in the past many
> times, but have never touched any 7200 series (or non-ISR for that matter)
> hardware.
> 
> Can anyone explain to me the purpose of the 12.2 images I see on CCO for
> this device?  

Warning: rant ahead.  If you don't want that, jump to the end...

<rant>
Mostly "give geeks that want to experiment more options how to shoot 
themselves".

Originally, 12.2S was targeted at service providers, and contained stuff
not in 12.2-main (MPLS, for example).

Then came 12.2SB, which was targeted at "broadband deployment", and if I
remember right, contained scalability enhancements for L2TP and other
broadband aggregation technologies.

12.2S is dead, dunno about 12.2SB.

Nowadays, there is 12.2SR*, which is there to hurt users of Cisco 7600 and
7200 platforms at the same time, but in different ways.

Let me explain that.  On the 7600, there is *only* 12.2SR* IOS, no 
12.3/12.4/15.0 IOS, as the hardware is different from the "general purpose" 
platforms, and the IOS development inside some Cisco business units does 
not understand that having a single IOS train across the board, with
similar features in all hardware-independent bits of IOS, is something
customers consider useful.

Customers complained, so they got 12.2SR* for the 7200 series as well - but
this is even more special IOS train, and all reports *I* have heard about
SR IOS on 7200 is "it does not work the way we want it to".
</rant>


So.  If you want my advice:

 - on the platforms where you are limited, use whatever IOS is available

 - on the platforms where you have a choice, go to the feature navigator
   (http://www.cisco.com/go/fn) and find an IOS version that has all the
   features that you want, and has *no letters* attached, and has a high
   number in (brackets).

 - the "letters thing" is as follows:  there is a 12.4 IOS train, that
   will only get bugfixes, so 12.4(20) is reasonably sane

 - "T" IOS gets new features all the time, so even a 12.4(20)T might
   be horribly broken.  12.4(20)T is not really related to 12.4(20), except 
   that both are descendents of 12.4(1) - one got new bugs, the other got
   the bugfixes.

 - "other letters" (12.4XJ etc.) are even more broken.

--> depending on your needs, go to 12.3(latest) or 12.4(latest).  Only if
    you need some features from T, go to 12.4(something)T(high) - or try
    15.0.

gert
-- 
USENET is *not* the non-clickable part of WWW!
                                                           //www.muc.de/~gert/
Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de
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