A 1974 Design Still Rules the Internet. Why? The 6 Design Philosophies of TCP/IP

Sat, 18 Jul 2026 09:30:00 +0800

TL;DR

TCP/IP is almost 50 years old. Every one of its rivals — the phone companies’ X.25, IBM’s SNA, the standards body’s OSI — is in a museum, yet it still carries every page you load today. It didn’t win by being the most advanced. It won through six design choices:

Packet switching: no private trains — everyone shares the highway. Cheap, and hard to kill;

Layering: each layer does one job and can be swapped out like a LEGO brick;

The end-to-end principle: keep the network dumb and put the smarts at the edges — so innovation never requires rewiring the network;

Best effort: the core promises nothing, reliability is bought à la carte — simple scales globally;

Rough consensus and running code: no kings, no voting — standards grow by working, not by decree;

Room for the future: from IPv4 to IPv6, from HTTP/1 to HTTP/3 — the foundation stays while everything above is rebuilt.

One sentence: good design doesn’t predict the future; it leaves room for it. This is the companion piece to Why Is Your WiFi Lagging? — that article explained what the network is and how to use it; this one explains why it was designed this way and how it survived half a century. All screenshots come from real systems and real protocol documents; IPs and hostnames are masked.

Why Is Your WiFi Lagging? Networks, TCP vs UDP, and the Two “5Gs” — Explained So a Kid Gets It

Sat, 18 Jul 2026 08:30:00 +0800

TL;DR

A network is a delivery service for computers: data is chopped into “parcels” (packets), labeled with “addresses” (IPs), and relayed by “sorting centers” (routers) hop by hop to the recipient.

TCP is a phone call: connect first, talk later, repeat anything that wasn’t heard — reliable but fussy. UDP is a postcard: drop it in the mailbox and hope — fast, but no delivery guarantee. Live video and games prefer UDP; files and web pages prefer TCP.

The three-way handshake is just the opening of a phone call: “Hello, can you hear me?” — “I can. Can you hear me?” — “I can too. Let’s talk.”

Wired is a private water pipe; WiFi is shouting in a crowded square — when everyone shouts at once, nobody is heard clearly. That is the number-one reason WiFi lags.

WiFi’s “5G” means the 5GHz frequency band (a wider lane). Your phone carrier’s “5G” means the 5th generation of mobile networks (a whole standard). They share a name and nothing else.

No jargon without an everyday analogy, but every number below comes from real measurements on real machines (all IPs and hostnames are masked). A kid can follow most of it; an adult won’t find it shallow.

TCPIP on Margrop Blog

A 1974 Design Still Rules the Internet. Why? The 6 Design Philosophies of TCP/IP

Why Is Your WiFi Lagging? Networks, TCP vs UDP, and the Two “5Gs” — Explained So a Kid Gets It