Fundamentals · Study deck
Protocol Pioneers: Web, Email, and Routing
TCP/IP joined networks, but people still needed useful ways to work through them.
Physics Phoebe is your guide for this deck.
After studying this chapter
Learning objectives
You will be able to:
- Explain: Those hand-offs make Vint Cerf and Bob Kahn, co-designers of TCP/IP, the protocol suite that enables the Internet actionable within: Vint Cerf (1943-) and Bob Kahn (1938-): The Fathers of the Internet.
- Explain: Today, he's working on: Solid -- a project to give users control over their personal data, addressing privacy concerns that have emerged 30+ years after the Web's creation.
- Explain: The Open Architecture Principle (Kahn's Insight): Any network -- wired, wireless, satellite, smoke signals -- can join the Internet if it can carry IP packets.
- Explain: The @ symbol was perfect.
Major section
Vint Cerf (1943-) and Bob Kahn (1938-): The Fathers of the Internet
Those hand-offs make Vint Cerf and Bob Kahn, co-designers of TCP/IP, the protocol suite that enables the Internet actionable within: Vint Cerf (1943-) and Bob Kahn (1938-): The Fathers of the Internet.
- Baran showed that packet networks could be resilient.
- Vint Cerf is partially deaf from birth.
Major section
Vint Cerf (1943-) and Bob Kahn (1938-): The Fathers of the Internet (continued)
The Open Architecture Principle (Kahn's Insight): Any network -- wired, wireless, satellite, smoke signals -- can join the Internet if it can carry IP packets.
- End-to-End Reliability (Cerf's Insight): Don't trust the network to be reliable.
- If a packet is lost, the receiving computer detects the gap (via sequence numbers) and asks the sender to retransmit.
- The network's job is simple: forward packets.
Major section
Vint Cerf (1943-) and Bob Kahn (1938-): The Fathers of the Internet (continued)
"I've always been interested in communication because I understand what it's like when communication fails.
- The Internet is fundamentally about connecting people and ideas -- making sure messages get through despite imperfect infrastructure.".
- This robustness reflects Cerf's personal understanding that communication cannot be taken for granted.
- By the 1990s, it was the foundation of the global Internet.
Major section
Tim Berners-Lee (1955-): World Wide Web Inventor
HTML marks linked documents, HTTP requests and returns them, and a URL or URI gives each resource a name.
- In 1989, CERN (the European physics lab) had thousands of researchers generating papers, datasets, and software.
- But there was no easy way to link related documents across different computers.
- Knowledge was siloed.
Major section
Tim Berners-Lee (1955-): World Wide Web Inventor (continued)
If you read a paper that referenced another paper, you had to manually search for it on a different system.
- HTTP is stateless -- each request is independent, making it simple and scalable.
- If CERN had patented it, the Web might have become a proprietary system like AOL or CompuServe -- walled gardens that eventually died.
- By 2026, over 5 billion people use the Web.
Major section
What Berners-Lee Made Possible
Every web-based IoT dashboard, every REST API, every cloud platform UI you use is built on Berners-Lee's HTTP.
- REST APIs: When your IoT device sends data to a web service (POST /sensor-data), it's using HTTP as the application protocol.
- That simplicity was Berners-Lee's design choice, influenced by his goal to make the Web accessible to everyone, not just experts.
- Today, he's working on: Solid -- a project to give users control over their personal data, addressing privacy concerns that have emerged 30+ years after the Web's creation.
Major section
Ray Tomlinson (1941-2016): Email Inventor
The pair turns Ray Tomlinson, who sent the first networked email in 1971 and chose the @ symbol into something the team can verify.
- In 1971, computers could run local messaging programs -- users on the same computer could leave messages for each other.
- But ARPANET had connected computers at different sites.
- The @ symbol was perfect.
Major section
Radia Perlman (1951-): "Mother of the Internet"
But graphs can have loops -- paths that circle back on themselves.
- Within seconds, a single packet can multiply into a broadcast storm that crashes the entire network.
- In the early 1980s, network engineers had to carefully plan network topologies to avoid loops.
- Any link that would create a loop is automatically blocked (disabled).
Major section
Radia Perlman (1951-): "Mother of the Internet" (continued)
The blocked connection removes a redundant path, showing how Spanning Tree Protocol prevents loops while retaining a connected network.
- Redundancy was risky -- if you added a backup link for resilience, you might accidentally create a loop that crashed everything.
- If a link fails, STP recalculates and unblocks backup paths.
- Network engineers can connect switches with redundant links for resilience, and STP ensures the active topology is always loop-free.
Major section
What Perlman Made Possible
Industrial IoT: Factory networks use STP to ensure a single cable cut doesn't isolate machines.
- Home Networks: Managed switches in home labs use STP to prevent accidental loops when users connect cables.
- You can connect switches in any topology, add redundant links for failover, and STP ensures it just works.
- Without STP, every IoT deployment would require careful network topology planning to avoid loops -- slowing deployment and increasing costs.
Deck summary
Key takeaways
Those hand-offs make Vint Cerf and Bob Kahn, co-designers of TCP/IP, the protocol suite that enables the Internet actionable within: Vint Cerf (1943-) and Bob Kahn (1938-): The Fathers of the Internet.
- The Open Architecture Principle (Kahn's Insight): Any network -- wired, wireless, satellite, smoke signals -- can join the Internet if it can carry IP packets.
- "I've always been interested in communication because I understand what it's like when communication fails.
- HTML marks linked documents, HTTP requests and returns them, and a URL or URI gives each resource a name.
- But graphs can have loops -- paths that circle back on themselves.
Retrieval practice
Recall check
Physics Phoebe says: answer from memory, then check your reasoning.
Q1An IoT device sends POST /sensor-data to a web service. Which role does HTTP play?
Show answer
Answer: A The chapter uses this example to connect device requests to web services.
Q2A building network adds redundant switch uplinks. What problem does the chapter associate with spanning tree?
Show answer
Answer: D The examples connect redundant links with loop prevention and recovery.
Print reference
Answers
Answer key.
- A · The chapter uses this example to connect device requests to web services.
- D · The examples connect redundant links with loop prevention and recovery.