1. draft-wing-v6ops-happy-eyeballs-ipv6 Happy Eyeballs: Trending Towards Success with Dual-Stack Hosts Dan Wing Andrew Yourtchenko {dwing, ayourtch}@cisco.com 1Happy Eyeballs - IETF79

2. 2 The Problem  IPv6 outages cause user frustration  “Turn on Dual Stack, It Will Work” causes 20 seconds of frustration  Solution: improve application behavior Happy Eyeballs - IETF79

3. 3 IPv6 Outages  Broken IPv6 tunnels  Single IPv6 peering  IPv4 responsiveness better than IPv6  “accidental IPv6”, IPv6 islands http://www.employees.org/~dwing/plot-speed.png Happy Eyeballs - IETF79

4. 4 Proposal: Send Probes, Learn, Quick Fallback 1.Send Probes: Try connecting to both IPv4 and IPv6  Similar to ICE (RFC5245) 2.Learn:  Use the past to predict the future  Avoids constant doubling of TCP SYNs 3.Quick Fallback Happy Eyeballs - IETF79

5. Current Behavior 5Happy Eyeballs - IETF79 DNS Server Web BrowserServer AAAA? example.com A? example.com example.com, AAAA=2001:db8::1 Example.com, A=192.0.2.1 TCP SYN, IPv6 TCP SYN, IPv4 about 20 seconds, depending on OS and browser IPv6 is broken

6. Happy Eyeballs Behavior 1: Probing 6Happy Eyeballs - IETF79 DNS Server Web BrowserServer AAAA? example.com A? example.com example.com, AAAA=2001:db8::1 Example.com, A=192.0.2.1 TCP SYN, IPv6 TCP SYN, IPv4 Behavior 2: Learn Remember IPv4 success immediate IPv6 is broken

7. Happy Eyeballs Behavior 3: Quick Fallback 7Happy Eyeballs - IETF79 DNS Server Web BrowserServer TCP SYN, IPv4 TCP SYN, IPv6 IPv4 breaks, IPv6 works aggressive (2-3 seconds) Lots of successful connections Behavior 2: Learn Remember IPv6 success

8. Happy Eyeballs Status  Probing implemented in Links browser  No, not Lynx, rather: http://links.sourceforge.net  Quick fallback needs more thought  “P” algorithm is our first cut  If IPvX is successful, try it first  Attaching to new network should clear Learned success 8Happy Eyeballs - IETF79

9. 9 Happy Eyeballs, Discussion  Today: Users frustrated with broken IPv6, and tempted to disable IPv6  Should we ask some applications to probe both IPv6 and IPv4? Happy Eyeballs - IETF79