11. The interface between the Application Entity and the Data Link Layer is called A-interface. 12. Brouters operate at both the protocols and at the data link layer for non-routable protocols. 13. Some taps operate at the physical layer of the OSI model rather than the data link layer . 14. PPP is commonly used as a data link layer protocol for connection over NBF, DECnet and AppleTalk. 15. The underlying Data Link Layer almost always poses limits to the maximum frame size ( See MTU ). 16. The gateway also operates at the data link layer ( Layer 2 ) of the OSI network model. 17. Some approaches utilize both the Network and Data link layer but do not consider the cross layer behaviors. 18. The interface between the Data Link Layer and the physical layer is called Medium Independent Interface ( MII ). 19. To alleviate these problems, bridging was created to communicate at the data link layer while isolating the physical layer. 20. Allowing direct data link layer communication between customer nodes exposes the network to various security attacks, such as ARP spoofing.
