Hello Everybody
I would like to know any major difference between sudo & RBAC as I am bit familiar with RBAC but not with sudo
That's too big a question to answer here; if you really want to know all of the differences you should read the documentation for both.
However important considerations are that RBAC is Solaris-only (I think - anyone seen it elsewhere?), whereas sudo is available for most Unix-like platforms.
Personally I find sudo more convenient to maintain because it's all in one file, unlike RBAC. However I think there are some advantages to RBAC as well, such as preventing people from logging in directly as a role, which can be achieved by other means for sudo but is not as straightforward. RBAC is ideally suited for meeting some auditing requirements, such as SOX.
Sudo is a cross platform userland command that provides something similar to pfexec with some more features like ability to specify the commands parameters and environment. Authentication is handled differently with sudo.
RBAC is a more secure wider solution tied to the (Solaris) operating system. It provides a much finer control about what can be authorized or forbidden.