Block Youtube site

How to limited speed download/upload with site Youtube ?
Anyway, i tried with these address: 74.125.71.136
74.125.71.190
74.125.71.91
74.125.71.93 with mark connection and mark package and putting in Queues, it does not work. And the other hand, if i limited by this site it work very well (www.jx.com.kh, IP:118.67.200.0/21).

I’m waiting for your solution…

Kind Regards,
Peang Hour

The dynamic content on youtube pages (i.e videos) does not come from those IP addresses. They sure use CDN to deliver videos to viewers so no guaranty those IP addressea are the same every time.
I recommend using L7 feature of mikrotik. you can find topics about it in the forum or wiki.

Could you please kindly to tell me how to do it in layer 7?

Kind Regards,
Peang Hour

Please spend sometime reading these pages to get familiar with the concept and also some practical examples:

http://www.mustnofee.com/tutorials/46-blocking-connection-using-mikrotik-with-layer7-protocol
http://blog.butchevans.com/2008/12/using-the-layer-7-filters-instant-messaging-example/
http://forum.mikrotik.com/t/what-is-the-benefit-of-layer-7-filter-in-mikrotik-3-22/44721/1
http://wiki.mikrotik.com/wiki/Manual:IP/Firewall/L7
http://wiki.mikrotik.com/wiki/Drop_IM_Using_L7

And also you must get help from WireShark (http://www.wireshark.org/download.html) to analyze your TCP/IP connections. Your computer firewall log can help you too.