14-1©2005 Raj JainCSE473sWashington University in St. LouisInternet Protocol Internet Protocol Version 6 (IPv6)Version 6 (IPv6)Raj Jain Washington UniversitySaint Louis, MO [email protected] slides are available on-line at:http://www.cse.wustl.edu/~jain/cse473-05/14-2©2005 Raj JainCSE473sWashington University in St. Louisq Limitations of IPv4 Addressingq IPv6 Enhancementsq IPv6 Addressesq IP v6 Headerq IPv6 Extension HeadersOverview14-3©2005 Raj JainCSE473sWashington University in St. LouisIP AddressesIP Addressesq Example: 164.107.134.5 = 1010 0100 : 0110 1011 : 1000 0110 : 0000 0101= A4:6B:86:05 (32 bits)q Maximum number of address = 232= 4 Billionq Class A Networks: 15 Million nodesq Class B Networks: 64,000 nodes or lessq Class C Networks: 254 nodes or less14-4©2005 Raj JainCSE473sWashington University in St. LouisIP Address FormatIP Address Formatq Three all-zero network numbers are reservedq 127 Class A + 16,381 Class B + 2,097,151 Class C networks = 2,113,659 networks totalq Class B is most popular.q 20% of Class B were assigned by 7/90 and doubling every 14 months ⇒ Will exhaust by 3/94q Question: Estimate how big will you become?Answer: More than 256!Class C is too small. Class B is just right.14-7©2005 Raj JainCSE473sWashington University in St. LouisHow Many Addresses?How Many Addresses?q 10 Billion people by 2020q Each person will be served by more than one computerq Assuming 100 computers per person ⇒ 1012computersq More addresses may be required sinceq Multiple interfaces per nodeq Multiple addresses per interfaceq Some believe 26to 28addresses per hostq Safety margin ⇒ 1015addressesq IPv6 Requirements ⇒ 1012end systems and 109networks. Desirable 1012to 1015networks1-8©2005 Raj JainCSE473sWashington University in St. LouisIPv6 EnhancementsIPv6 Enhancements1. Expanded address space: 128 bit2. Address auto-configuration: Dynamic assignment 3. Increased addressing flexibility: Anycast + Multicast4. Improved option mechanism: Extension Headersq Improved speed and simplified router processing 5. Support for resource allocationq Replaces type of serviceq Labeling of packets to particular traffic flow14-9©2005 Raj JainCSE473sWashington University in St. LouisIPv6 AddressesIPv6 Addressesq 128-bit long. Fixed sizeq 2128= 3.4×1038addresses ⇒ 665×1021addresses per sq. m of earth surfaceq If assigned at the rate of 106/μs, it would take 20 yearsq Expected to support 8×1017to 2×1033addresses8×1017⇒ 1,564 address per sq. mq Allows multiple interfaces per host.q Allows multiple addresses per interface q Allows unicast, multicast, anycastq Allows provider based, site-local, link-local14-10©2005 Raj JainCSE473sWashington University in St. LouisColonColon--Hex NotationHex Notationq Dot-Decimal: 127.23.45.88q Colon-Hex: FEDC:0000:0000:0000:3243:0000:0000:ABCDq Can skip leading zeros of each wordq Can skip one sequence of zero words, e.g., FEDC::3243:0000:0000:ABCD::3243:0000:0000:ABCDq Can leave the last 32 bits in dot-decimal, e.g., ::127.23.45.88q Can specify a prefix by /length, e.g., 2345:BA23:0007::/5014-11©2005 Raj JainCSE473sWashington University in St. LouisLocalLocal--Use AddressesUse Addressesq Link Local: Not forwarded outside the link, FE:80::xxx0 Interface ID1111 1110 1010 bits n bits 118-n! Site Local: Not forwarded outside the site, FE:C0::xxx! Provides plug and play0 Subnet ID1111 1110 1110 bits n bits m bitsInterface ID118-n-m bits14-12©2005 Raj JainCSE473sWashington University in St. LouisMulticast AddressesMulticast Addressesq T = 0 ⇒ Permanent (well-known) multicast address, 1 ⇒ Transientq Scope: 1 Node-local, 2 Link-local, 5 Site-local,8 Organization-local, E Globalq Predefined: 1 ⇒ All nodes, 2 ⇒ Routers, 1:0 ⇒ DHCP servers8 bits 4 bits 4 bits 112 bitsFlags Scope1111 1111 Group ID0 0 0 T14-13©2005 Raj JainCSE473sWashington University in St. LouisMulticast Addresses (Cont)Multicast Addresses (Cont)q Example: 43 ⇒ Network Time Protocol Serversq FF01::43 ⇒ All NTP servers on this nodeq FF02::43 ⇒ All NTP servers on this linkq FF05::43 ⇒ All NTP servers in this siteq FF08::43 ⇒ All NTP servers in this organizationq FF0E::43 ⇒ All NTP servers in the Internet14-14©2005 Raj JainCSE473sWashington University in St. LouisHeaderHeaderVer Traffic Class Flow LabelPayload Length Next Header Hop LimitSource AddressDestination AddressVersion IHL Type of Service Total LengthIdentification Flags Fragment OffsetTime to Live Protocol Header ChecksumSource AddressDestination AddressPaddingOptionsq IPv6:! IPv4:14-15©2005 Raj JainCSE473sWashington University in St. LouisIP v6 HeaderIP v6 Headerq Version: 6q Traffic Class: Classes or priorities of packetq Flow Label: Used by hosts requesting special handlingq Payload length: Includes all extension headers + dataq Next Header: Extension header or next layer upq Source Addressq Destination address14-16©2005 Raj JainCSE473sWashington University in St. LouisProtocol and Header TypesProtocol and Header TypesDecimal Keyword Header TypeHBH Hop-by-hop (IPv6)1 ICMP Internet Control Message (IPv4)2 IGMP Internet Group Management (IPv4)2 ICMP Internet Control Message (IPv6)3 GGP Gateway-to-Gateway4 IP IP in IP (IPv4 Encaptulation)5STStream6TCP17 UDP29 ISO-TP443 RH Routing Header (IPv6)44 FS Fragmentation Header (IPv6)45 IDRP Interdomain Routing51 AH Authentication header (IPv6)52 ESP Encrypted Security Payload59 Null No next header60 ISO-IP CLNP88 IGRP89 OSPF Open Shortest Path First14-17©2005 Raj JainCSE473sWashington University in St. LouisIPv6 vs IPv4IPv6 vs IPv4q 1995 vs 1975q IPv6 only twice the size of IPv4 headerq Only version number has the same position and meaning as in IPv4q Removed: header length, type of service, identification, flags, fragment offset, header checksumq Datagram length replaced by payload lengthq Protocol type replaced by next headerq Time to live replaced by hop limitq Added: Priority and flow labelq All fixed size fields.14-18©2005 Raj JainCSE473sWashington University in St. LouisIPv6 vs IPv4 (Cont)IPv6 vs IPv4 (Cont)q No optional fields. Replaced by extension headers.q 8-bit hop limit = 255 hops max (Limits looping)q Next Header = 6 (TCP), 17 (UDP),14-19©2005 Raj JainCSE473sWashington University in St. LouisExtension HeadersExtension HeadersMost extension headers are examined only at destination1. Hop-by-Hop Options 2. Fragmentation: All IPv6 routers can carry 536 Byte payload 3. Routing: Loose or tight source routing4. Destination