caching yum updates in CentOS with proxy and mirroring to other systems
 

I have dozens of CentOS and Ubuntu in my network. It is not easy and efficent to update every systems because of bandwidth. I really want to centralize the updates and let other systems point it.
I know about rsync. But I want to use caching proxy servers if possible. Can squid proxy or others do this need?

You can cache with squid, you'll need a big cache to benefit to any real extent though. But if you've the disk space, I'd suggest you create a proper mirror with mrepo http://dag.wieers.com/home-made/mrepo/

I have been working with it. There are many examples in it. I don't know which one is my need. I am only experienced with /etc/yum*. I do not understand the concepts well with mrepos.

What I have is Centos 6.3 and mostly 6.4. I don't know where to start. Can you genius help me step by step?

just read the setup guide, there's really nothing that tricky about it. you're just cloning a remote repository locally and making it accessible via a web server.