Upgrading from IOS release 12.4 to 15

[Kevin Melton]

I currently am supporting a 3845 running 12.2.24.T on one side of an MPLS circuit and then a 3825 running 12.4.23 Mainline on the other end of the circuit.

I was reading the Q  & A section about release 15 M and T.  Is there any reason (other than hardware resources) why I would not go ahead and move to release 15.

Also I noticed in the Software download section that there were 3 different releases available for the 3845 for version 15.  they were 15.0.1M1(ED), 15.0.01-XA1(ED), 15.1.1-XB(ED).

I do not understand the transtion from M1 to XA1 to XB.  Can this be explained?

Thanks for any input

Kevin

[Reza Sharifi]

Kevin,

Have a look at this PDF document.  It explains the differences.

http://www.cisco.biz/en/US/prod/collateral/iosswrel/ps8802/ps10587/ps10591/ps10621/ppt_c97-564603.pdf

HTH

Reza

[Giuseppe Larosa · Accepted solution]

Hello Kevin,

your routers have current IOS releases.

Unless there is a new feature that you need present only on 15 IOS I would stay with 12.4T for a while.

About  the different versions: well it is not a new story.

However, for examples release notes for 15XB are here:

http://www.cisco.com/en/US/docs/ios/15_1/release/notes/1511xbrn.html

15 XB

this release supports a new routing paradigm called LISP

Locator/ID Separation Protocol (LISP) is a next-generation routing feature. LISP can be used for any multi-homing environments while reducing operational complexities.

This is just an example I think you can focus on mainline 15.01M for normal uses. These other images have specific uses.

Hope to help

Giuseppe

[Leo Laohoo]

I have a number of 2821 routers I recently upgraded to 15.1.1 without any issues.  One of the things I had to check is the amount of DRAM required.  I also needed a new CF so I purchased a 2Gb CF, swapped out the rest and restarted the router.

[Ricardo Velazquez]

One big issue to migrate to version 15 is security purpose, as the MITRE group has found and published a vulnerability list for Cisco IOS versions 12.4 and most if not all the recommended fixes is to upgrade to 15.1M, here are just some of the major links for the security vulnerabilities for DoS attacks on IOS 12.4.

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20130925-ntp#fixes

http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2013-5472

there are more, but you can Google search to find them out or just look around the MITRE page.