OSPF Designated Router, Back Designated Router, and DR Others. Do you know the answers? Get $200 worth of network software for free here: https://goo.gl/L3qJoN
My full course is here: http://www.ccnax.com
Subscribe to learn how to pass the CCNA 200-125 exam. Also includes content for the ICND1 100-105 and ICND2 200-105 exams.
What do you want to learn? Let me know via the comments.