1. 1 Introduction IETF RFC1752 – a specification for a next-generation IP (IPng) IETF RFC2460 – IPv6 specification Designed to accommodate the highest speed network and a mix of data stream. Important driving force – need more IP addresses Migration from today’s IPv4 to IPv6 – “change jet engine while keeping it flying”

2. 2 IPv6 Addresses IPv6 uses 128 bits to support at least one billion networks IPv6 still uses the concept of network number and host number with extension to several levels To convert existing IPv4 addresses to IPv6 addresses –32 bits of IPv4 address are kept as the lower bits of IPv6 address –Adding a fixed prefix of 96 bits with 80 zero bits followed by 16 zero bits or 16 one bits IPv6 addresses can use colon hexadecimal notation with a colon to separate every 16 bits

3. 3 40 bytes basic fixed-size header –Include 16 bytes each for source and destination IP addresses Optional extension header(s) follow the basic header Payload Length  2 16 bytes = 65536 bytes IPv6 Header Format Payload Length (16 bits) Version Traffic Class (8 bits) Flow Label (20 bits) Options (if any, <=40 bytes) Optional Extension Headers >= ten 32-bit words 32-bit word 031 TTL Time-to-LiveHop Limit Source IP address (128 bits) Destination IP address (128 bits)

4. 4 IPv6 Header Format (cont.) 40 bytes basic header Optional extension headers include the following fields Router processed headers –Hop-by-hop options header –Routing header Ethernet type value (hex-86dd) assigned for IPv6

5. 5 IPv6 Datagram Priority 4-bits priority field –0 – 7: lower priority traffic for which the source is providing congestion control (e.g. TCP …) –8 – 15: higher priority traffic that does not back off in response to congestion (e.g. real time traffic …)

6. 6 IPv6 Datagram Priority (cont.) Priority ValueMeaning 0Uncharacterized traffic 1“Filler” traffic (e.g. netnews) 2Unattended data transfer (e.g. e-mail) 3(Reserved) 4Attended bulk transfer (e.g. FTP, NFS) 5(Reserved) 6Interactive traffic (e.g. telnet) 7Internet control traffic (e.g. SNMP, routing protocols) 8Most willing to have discarded under the condition of congestion 15Lest willing to have discarded under the condition of congestion