What-are-the-differences-between-Point-to-Point-Tunneling-Protocol-PPTP-and-Layer-2-Tunneling-Protocol-L2TP-

Write the short discussion:

What are the differences between Point-to-Point Tunneling Protocol (PPTP) and Layer 2 Tunneling Protocol (L2TP)? Please specify some examples where one protocol is more appropriate than the other.
What are the differences between a VPN mesh topology and a VPN star topology? How would you compare VPN topologies to network topologies?

Write at least 1 page (2 paragraphs) for each question, total 2 pages. Need References