IOS-12.0S

From Cisco Clue

Cisco 12.0S is currently (other than the IOS-XR that will operate on the GSR platform) the only image supported officially on the GSR platform. 12.0S is ran across the GSR, 7500, 10k, 10720 and 7200 platforms.

Each release of code is delievered as 12.0(XX)S, where XX is the latest release to have new features introduced. In addition, maintenance releases have their own sequential numbering scheme.

For example: 12.0(23)S6 would be the 6th maintenance release of code for 23S.

The general rule is that new features are not introduced in maintenance releases, however, this is not always the case. Customers have been known to push for new functionality in maintenance releases.

Some common 12.0S variants:

12.0SP - Temporary release vehicle to introduce support for 10720 (yellow brick)

      - now EOL and integrated in main branch from 12.0(xx)S

12.0SX - ???

12.0SY -

12.0SV - Sprint special release to support BGP VPNs over L2TPv3

12.0SW - Sprint special release to support BGP VPNs over L2TPv3

      - now EOL and integrated in main branch from 12.0(xx)S ?

12.0SZ - Temporary release vehicle for additional features

12.0S(xx)S#a, b, c, etc (Ie: 12.0(26)S4b) - Special custom builds for particular customers

There is no 12.0(29)S for the GSR due to time commitments.

The CCMSBU (GSR, 7600, CRS-1 business unit) has taken over primary IOS development of 12.0S starting at 12.0(31)S.