The world in which IPv6 was a good design (2017)
Critiques of IPv6’s design resurface around a 2017 blog post arguing that the protocol failed to adequately address modern needs like mobility, security, and simplicity, and that it baked in outdated assumptions from early Internet routing. Commenters counter that many proposed “better” alternatives end up recreating IPv6’s core ideas, and that real-world problems stem more from deployment politics, legacy IPv4 workarounds (like NAT and CGNAT), and misleading tooling than from the protocol itself. The exchange highlights enduring tensions between end-to-end connectivity and firewalls, incremental deployability versus architectural purity, and whether the Internet should evolve via new network layers or application-layer overlays such as QUIC and VPN-style systems.
WiFi, CSMA, and topology
- Debate over the article’s claim that CSMA/CD is “gone”:
- Several point out WiFi has always used CSMA/CA, plus RTS/CTS and now OFDMA; collisions are still managed, just differently.
- Ethernet switched networks no longer need CSMA/CD; WiFi still shares a medium, but access points and PHY tricks make it behave more like a switch.
- Topology characterization differs: some argue WiFi is logically star over a shared (bus-like) RF medium.
Mobility, sessions, and routing
- Disagreement on whether changing IPs mid-connection is practical.
- Critics of the article say it ignores how intermediate routers learn new locations; purely UUID-based session IDs don’t solve L3 routing or DoS issues.
- Others note QUIC/multipath-style designs decouple L4 identity from L3 and can re-establish sessions after roaming, accepting some packet loss.
- Mobile IP and Mobile IPv6 are mentioned as real but largely undeployed due to ecosystem and ISP constraints.
IPv6 design, ARP/NDP, and layering
- Some like the article’s historical overview but object to its negativity about ARP, arguing it enabled simple LAN IP without routers.
- Others defend IPv6’s Neighbor Discovery as cleaner than ARP (ICMPv6, multicast instead of broadcast), though there’s back-and-forth on whether either truly avoids “layering violations.”
- A recurring theme: many alternative proposals or “IPv4+” ideas end up functionally equivalent to IPv6, or were actually tried and rejected.
IPv4 + NAT vs IPv6
- One camp: IPv4 with NAT (and even CGNAT) is “good enough” for most users who just need outbound web access; simple P2P is not seen as essential.
- Opponents highlight CGNAT pain (e.g., hosting small game servers), loss of easy end-to-end connectivity, and centralization risks.
- Discussion of IPv6 privacy addressing and fears that per-device global addresses could enable per-user charging; others counter with address rotation mechanisms.
Deployment pain, politics, and dual stack
- Multiple anecdotes of flaky dual-stack behavior (e.g., apt timeouts) leading admins to disable IPv6.
- Some blame IAB/IETF “end-to-end purity,” slow adaptation to real-world security/firewall needs, and complex address-selection rules for delaying adoption.
- Others argue the real issue is path dependence and that any new “better” protocol would require essentially the same painful global upgrade.