I am new to Linux (we Are using RHEL 6). If anybody could help me how to take full Linux backup on tape with step by step option will be highly appreciated.

Regards,
Moin

If you have paid for RHEL then you can call their support line and they will explain how to do it. If you haven't paid for it then you might consider using CentOS.
Ciao,
jdk (not java)

thank you for the advice.

Yes we paid for the support.

Fantastic! I'm sure the nice people at RHEL would be more than happy to help you and after all, you did pay for their service. You might as well use it.

jdk (not java)

The first step you should take is to use the search function on this site, where this has been asked (and answered), many, MANY times. You can also try Google. You don't say what kind of tape device, nor what you mean by 'backup'. Making a copy is not the same thing...and you don't say if you want incremental backups/full backups, how often you want to take them, what your rotation method is going to be, etc. There are packages such as bacula or zmanada that can do backups too.

Also, you don't say whether you want to do a bare-metal restore, or if you just need files.