Charles M. Kozierok (September 20, 2005). "Data Link Layer (Layer 2)". tcpipguide.com. Archived from the original on May 20, 2019. Retrieved January 9, 2016.
Charles M. Kozierok (September 20, 2005). "Data Link Layer (Layer 2)". tcpipguide.com. Archived from the original on May 20, 2019. Retrieved January 9, 2016.