MPLS TE configuration, path protection! Command accepted but obsolete, unreleased or unsupported; see documentation

[tchindawill]

Hello, i would appreciate if someone can suggest me something.

When I issue the command " tunnel mpls traffic-eng path-option protect 2 explicit name R3-R1 " for tunnel path protection,

the system replies:

% Command accepted but obsolete, unreleased or unsupported; see documentation.

% Not valid in active submode of Label Switching mode

It seems that my IOS version does not support that command! Should i definitively upgrade the system?

my platform: IOS 12.3 (33) SRB5

Thanks in advance!

[Nagendra Kumar Nainar]

For completeness, this question was discussed in below link,

https://supportforums.cisco.com/discussion/12197746/mpls-te-configuration-path-protection-command-accepted-obsolete-unreleased-or

-Nagendra