Advanced Networking: HTTP/2, CDNs, and TLS

Lesson Promise

By the end of this lesson, you will understand how HTTP/2 multiplexing eliminates connection bottlenecks, how CDNs and anycast reduce latency by placing content closer to users, and how TLS 1.3 reduces handshake cost.

Narration Draft

Part 1 — HTTP/1.1 Limitations (4:00) Head-of-line blocking: one request at a time per connection. Text-based headers add overhead. Browser connection limits.

Part 2 — HTTP/2 Improvements (5:00) Binary framing layer. Multiplexing: multiple streams over one connection. HPACK header compression. Server push.

Part 3 — Connection Management (4:00) Connection pooling. Keep-alive reuse. TLS handshake cost. Why connection setup dominates first-byte latency.

Part 4 — CDNs and Anycast (5:00) CDN edge servers cache static content geographically. DNS directs users to the nearest edge. Anycast assigns the same IP to multiple servers; BGP routes to the nearest.

Part 5 — HTTP/3 and QUIC (4:00) QUIC over UDP combines transport and TLS handshake. Zero-RTT for returning clients. Eliminates TCP head-of-line blocking.

Visual Sequence

1. HTTP/1.1 head-of-line blocking: multiple requests queued on one connection
2. HTTP/2 multiplexing: interleaved frames from multiple streams on one connection
3. CDN edge map: user → nearest edge server → origin
4. Anycast BGP routing: same IP on three continents, packets route to the nearest
5. TLS 1.3 vs 1.2 handshake comparison: 1 RTT vs 2 RTT

Companion Material

• Article: HTTP/2 Multiplexing
• Article: CDNs and Anycast
• Article: What Happens When You Call an API
• Article: TLS Security
• Video: HTTPS Request Lifecycle