IPv6 Tarik Cicic University of Oslo December 2001 Overview • New generation IP protocol (IPv6): – why do we need it – support for new Internet services • discussion 2 Internet technology Users • Idea: exchange of information between e-mail Web voice remote systems • all users, with their TCP UDP individual needs, using different applications, on different systems and IP various network interconnects, must be able to communicate! ATM Ethernet Functionality 3 1
Internet today: Problem list • Address space insufficient • traffic congestion implies waiting for all • network configuration and reconfiguration • lack of Quality of Service support • no built-in security mechanisms The best solution to these problems is provided through improving IP itself. 4 Internet 2 terminology • IP or IPv4: internet protocol in use today • IPv6: new generation internet protocol (formerly called IPng), experimentally deployed today • Internet 2: experimental IP network. Originally an American research project, now also research project in Norway. 5 IPv6: improvements • The Internet (with IPv4) is a tremendous success • IPv6 should inherit good features from IPv4, solve the problems and add functionality: – huge address room, autoconfiguration – Quality of Service attributes – mobility through improved routing – security support – simplicity – extensibility 6 2
IPv6 packets • Addresses: 128 bit instead of 32 • IPv6 header is simpler than IPv4 • Quality of Service through priority field and flow label • optional parameters in “extension headers” Fixed size Optional Variable size Extension Header Payload headers 7 IPv6 vs. IPv4 header Version Hlen TOS Length Ident Flags Offset IPv4 TTL Protocol Checksum Source address Destination address Options (variable) Pad (variable) 32 bit Flow label Header has got VersionTraffic Class Payload length Next header Hop limit a fixed length Source address 4 x 32 = 128 bit IPv6 Destination address 4 x 32 = 128 bit 8 Addressing • 128 bits give 3.4 10 38 addresses (couple of thousands per square meter of the Earth) • this – covers traditional needs ☺ – opens for new services • geographical addressing • hierarchical multicast etc. • autoconfiguration of networking equipment • anycast addresses 9 3
Extension headers • All non-essential information is moved from the IP header to the extension headers: – hop-by-hop header (per-hop processing) – destination options header – routing header (e.g. explicit route) – fragment header (if payload is larger than the MTU) – authentication header – encapsulating security payload header 10 Quality of Service • QoS-friendliness achieved through the traffic class and flow label fields • traffic class sample: 0 urgent network maintenance 2 CBR real-time service 3 VBR service …. 8 telnet 10 www 15 e-mail • IPv6 is not a resource reservation protocol! • flow label can be used in QoS routing 11 Mobile computing • Destination address change is a challenge for mobile computing based on IPv4 • routing extension header adds new functionality • explicit routing: – incoming packets with an explicit route should be answered to with the inverse explicit route – can move from net to net without breaking TCP connections! 12 4
Security • Built-in authentication and privacy mechanisms (by special headers) • in IPv4, the security was left to higher level protocols (applications, SSL) • now every packet (even the addresses) can be encrypted • one cannot present himself as another user • lower overhead, higher security than today. 13 Transition mechanisms • Smooth transition: – dual protocol stack – tunneling – name resolution (DNS) – Network Address Translation • these mechanisms are in place today. 14 … but when will it come? • IPv6 is still not widely used: – 4 billion addresses we have today is sufficient? – new host and router software costs? – no substantial improvements compared to IPv4? 15 5
IPv4/v6 comparison IPv4 IPv6 Conclusion Big, poorly CIDR and NAT can Address space Huge utilized extend IPv4 life Header and Variable Fixed, Routers are getting routing size, much simple faster, unclear complexity to compute Mobility, There services can No support Supported security be added to IPv4 Quality of No support No support Tiny difference Service – + 16 6
Recommend
More recommend
