Mark Kempf Invented the Ethernet Bridge | Generated by AI
Question: What is the life story of Mark Kempf, and how was he involved in networking as the author/inventor of the Ethernet bridge?
Answer:
Mark Kempf is a networking engineer best known for inventing the first Ethernet MAC bridge (also known as a learning bridge or Layer 2 switch) in 1983 while working at Digital Equipment Corporation (DEC).
In 1983, engineer Alan Kirby approached Kempf with the idea of eliminating shared media limitations in Ethernet by using store-and-forward switching to connect separate Ethernet segments. Kempf, a principal engineer in DEC’s Networking Advanced Development group, quickly developed the concept of a “learning bridge” the next day. This device automatically learned MAC addresses and forwarded packets only to the relevant segment, significantly improving performance and scalability over traditional shared Ethernet (which suffered from collisions on larger networks).
The result was the LANBridge 100, DEC’s first commercial two-port Ethernet bridge product, introduced shortly after. This innovation helped Ethernet compete against rivals like Token Ring and FDDI by allowing larger, segmented networks without full routing overhead. Kempf holds patents related to this technology, and DEC licensed the MAC bridge patent royalty-free, enabling IEEE standardization and widespread adoption by other vendors (e.g., Kalpana’s multi-port switches).
Kempf contributed to other DEC networking advancements, including terminal servers, host security software, optical networking, and high-performance switches like the GigaSwitch. He later held executive roles (e.g., Vice President of Engineering) at companies such as Raptor, Okena, Cisco, and BitSight Technologies. He is co-inventor on nearly 20 patents in networking and security, co-author of technical papers and book chapters, and has continued research and consulting, including with MIT.
Little public information exists on his early life, education, or personal details beyond his professional achievements at DEC in the 1980s–1990s.
Note: There are multiple individuals named Mark Kempf (e.g., a retired U.S. Navy captain in defense tech, others in finance or software), but the one associated with the Ethernet bridge is the DEC engineer.
References:
- IEEE Spectrum: How DEC Engineers Saved Ethernet
- Hackaday: How DEC’s LANBridge 100 Gave Ethernet A Fighting Chance
- Packet Pushers Podcast: History of Networking: How Bridging Saved Ethernet
- Wikiwand: Network Switch (citing invention)