IPv6 Header Cleanup No checksum >) Why checksum just the IP header? Efficiency: If packet corrupted at hop 1, don't waste b/w transmitting on hops 2. N Useful when corruption frequent, b/w expensive Today: Corruption rare, b/w cheap Different options handling >)IPv4 options: Variable length header field. 32 different options ly used No development/ many hosts/routers do not support Worse than useless: Packets wloptions often even get dropped Pr sedin“ slow path options:"Next header pointer Combines“ protocol"and“ options" handling Next header:“TcP","“UDP”,etc. Extensions header: Chained together Makes it easy to implement host-based options One value"hop-by-hop"examined by intermediate routers Things like"source route"implemented only at intermediate hops 99 IPv6 Header Cleanup No checksum » Why checksum just the IP header? – Efficiency: If packet corrupted at hop 1, don’t waste b/w transmitting on hops 2..N. – Useful when corruption frequent, b/w expensive – Today: Corruption rare, b/w cheap Different options handling » IPv4 options: Variable length header field. 32 different options. – Rarely used – No development / many hosts/routers do not support Worse than useless: Packets w/options often even get dropped! – Processed in “slow path”. » IPv6 options: “Next header” pointer – Combines “protocol” and “options” handling Next header: “TCP”, “UDP”, etc. – Extensions header: Chained together – Makes it easy to implement host-based options – One value “hop-by-hop” examined by intermediate routers Things like “source route” implemented only at intermediate hops