IPv6 Cleanup- Router-friendly a bit about router architecture: Common case: Switched in silicon(“ fast path”) 》 Weird cases: Handed to CPu(“ slow path”,or“ process switched") 》 Typical division: Fast path: Almost everything Slow path Fragmentation TTL expiration(traceroute IP option handling > Slow path is evil in today s environment Christmas Tree"attack sets weird IP options, bits, and overloads router Developers can't(really use things on the slow path for data flow If it became popular, theyd be in the soup! >Other speed issue: Touching data is expensive. Designers would like to minimize accesses to packet during forwarding 88 IPv6 Cleanup - Router-friendly A bit about router architecture: » Common case: Switched in silicon (“fast path”) » Weird cases: Handed to CPU (“slow path”, or “process switched”) » Typical division: – Fast path: Almost everything – Slow path: Fragmentation TTL expiration (traceroute) IP option handling » Slow path is evil in today’s environment – “Christmas Tree” attack sets weird IP options, bits, and overloads router. – Developers can’t (really) use things on the slow path for data flow. If it became popular, they’d be in the soup! » Other speed issue: Touching data is expensive. Designers would like to minimize accesses to packet during forwarding