ÉCOLE POLYTECHNIQUE FÉDÉRALE DE LAUSANNE The Internet Protocol (IP) Part 2: IPv6 Jean‐Yves Le Boudec Fall 2009 1 1
Contents 1. IPv6 2. NATs 3. Interworking IPv4 / IPv6 4. Routing Implications 5. Recap Some slides come from: ipv6-g6-tutorial.pdf by Mohsen.Souissi@nic.fr Some slides come from: RIPE 40 Meeting by Florent.Parent@viagenie.qc.ca 2 2
1. IPv6 The current IP is IPv4. IPv6 is the next version of IP Why a new version ? Why a new version ? IPv4 address space is too small (32 bits). It will be exhausted some day. IP over cellular, UMTS What does IPv6 do ? Redefine packet format with a larger address: 128 bits Otherwise essentially the same as IPv4 but with minor improvements on Otherwise essentially the same as IPv4, but with minor improvements on header format Facilitate hardware implementation – not seen in this module We now review how the IPv6 addresses are made and what new facilities this allows Why IPv6 and not IPv5 ? Because the version number 5 is already used by an experimental Protocol called ST2, used to provide quality of service for example in military networks. 3 3
IPv6 Addresses 3b 45b 16b 64b 001 prefix by prov. subnet interface Id allocated by IANA allocated by customer and org / provider Address type 4 4
IPv6 Addresses: Notation IPv6 address is 16B = 128 bits Notations: 1 piece = 16 bits = [0‐4 ]hexa digits; pieces separated Notations: 1 piece 16 bits [0 4 ]hexa digits; pieces separated by “:” :: replaces any number of 0s; appears only once in address Examples 2001:80b2:9c26:0:800:2078:30f9 permanent IPv6 address (allocated 2001 and later) 2002:80b2:9c26:0:800:2078:30f9 6to4 IPv6 address of dual stack host with IPv4 address 128.178.156.38 and f MAC address 08:00:20:78:30:f9 0:0:0:0:0:FFFF:128.178.156.38 IPv4 mapped address (IPv4 only host) ::FFFF:80b2:9c26 same as previous FF02::43 all NTP servers on this LAN all NTP servers on this LAN 0:0:0:0:0:0:0:0 = :: = unspecified address (absence of address) hosts may have several addresses addresses are: unicast, anycast or multicast url with IPv6 address: use square brackets http://[ 2001:80b2:9c26:0:800:2078:30f9 ]/index.html 5 5
From RFC4291, Feb 2006 Addr ess t ype Bi nar y pr ef i x I Pv6 not at i on Addr ess t ype Bi nar y pr ef i x I Pv6 not at i on - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Unspeci f i ed 00. . . 0 ( 128 bi t s) : : / 128 Loopback 00. . . 1 ( 128 bi t s) : : 1/ 128 M ul t i cast 11111111 FF00: : / 8 Li nk- Local uni cast 1111111010 FE80: : / 10 G l obal Uni cast ( ever yt hi ng el se) 6 6
INTERNET P TERNET PROTOCO COL V L VERSIO ION 6 N 6 ADDRESS RESS SPACE E (IAN (IANA) [last updated 27 February 2006] IPv6 Prefix Allocation Reference Note IPv6 Prefix Allocation Reference Note ----------- ---------- --------- ---- 0000::/8 Reserved by IETF [RFC3513] [1] [5] 0100::/8 Reserved by IETF [RFC3513] 0200::/7 Reserved by IETF [RFC4048] [2] [0] The IPv6 address management function was formally delegated to 0400::/6 Reserved by IETF [RFC3513] IANA in December 1995 [RFC1881]. 0800::/5 Reserved by IETF [RFC3513] 1000::/4 Reserved by IETF [RFC3513] [1] The "unspecified address", the "loopback address", and the IPv6 Addresses with Embedded IPv4 Addresses are assigned out of the 2000::/3 Global Unicast [RFC3513] [3] 0000::/8 address block. 4000::/3 Reserved by IETF [RFC3513] y 6000::/3 Reserved by IETF [RFC3513] [2] 0200::/7 was previously defined as an OSI NSAP-mapped prefix set [RFC-gray-rfc1888bis-03.txt]. This definition has been deprecated as of December 8000::/3 Reserved by IETF [RFC3513] 2004 [RFC4048]. A000::/3 Reserved by IETF [RFC3513] C000::/3 Reserved by IETF [RFC3513] [3] The IPv6 Unicast space encompasses the entire IPv6 address range with the exception of FF00::/8. [RFC3513] IANA unicast address E000::/4 Reserved by IETF [RFC3513] assignments are currently limited to the IPv6 unicast address F000::/5 Reserved by IETF [RFC3513] range of 2000::/3. IANA assignments from this block are registered F800::/6 Reserved by IETF [RFC3513] in the IANA registry: iana-ipv6-unicast-address-assignments. FC00::/7 Unique Local Unicast [RFC4193] [4] FEC0::/10 was previously defined as a Site-Local scoped address FE00::/9 Reserved by IETF [RFC3513] prefix. This definition has been deprecated as of September 2004 FE80 /10 Li k L FE80::/10 Link Local Unicast [RFC3513] l U i t [RFC3513] [RFC3879]. [RFC3879] FEC0::/10 Reserved by IETF [RFC3879] [4] [5] 0000::/96 was previously defined as the "IPv4-compatible IPv6 FF00::/8 Multicast [RFC3513] address" prefix. This definition has been deprecated by [RFC4291]. 7 7
IPv6 Multicast Addresses 8b 4b 4b 112 bits 11111111 flgs scpe group Id flgs: (flags)= 000T T=0: well-known T=1: transient scpe: (scope) 0: reserved 1: node local 2:link local 5: site local 8: org local E: global F: reserved examples: FF01::43 = all NTP servers on this node FF02::43 all NTP servers on this link FF02::43 = all NTP servers on this link FF05::43 = all NTP servers on this site FF0E::43 = all NTP servers in the Internet reserved addresses: FF0x::1 all nodes in the scope (x=1, 2) FF0x::2 all routers in the scope (x=1, 2) FF02::1:0 all DHCP servers/relay on this link solicited node multicast: FF02::1:XXXX:XXXX where XXXX:XXXX= lowest order 32 bits of unicast addr. 8 8
The New Address Format Allows Plug and Play Automatic assignment of addresses in hosts is possible, using MAC address This is called “stateless” autoconfiguration The next slide shows how it works: 1. Host creates a link local unicast address from its MAC address (cannot be used outside a LAN, but can be used to reach a router). Validity of address is verified by sending a packet to a special multicast address that only nodes with the same MAC address can have. 2. Host asks for a router present and gets a prefix. 9 9
Stateless Autoconfiguration Overview host A other host on-link router on-link A attempts to acquire its link local A attempts to acquire its link local unicast address: FE80::0800:2072:8CFC 1. NS, multicast to FF02::1:2072:8CFC (dupl test) A accepts its link i li k local unicast address: FE80::0800:2072:8CFC 2. RS, multicast to FF02::2 router response with prefix 4001:41:1234:156:128 A accepts its global (if M flag set : unicast address: use DHCP instead) 4001:41:1234:156:128:08 00:2072:8CFC 10 10
IPv6 Host Configuration Example Output of "netstat ‐q" at lrcsun12 ; Interface Destination/Mask Phys Addr Ref State Interface Destination/Mask Phys Addr Ref State --------- ------------------- ---------- ------- --------------- le0#v6 ff02::2/128 33:33:00:00:00:02 1 REACHABLE le0#v6 ff02::1:80b2:9c26/128 33:33:80:b2:9c:26 1 REACHABLE le0#v6 fe80::1:0:800:2078:30f9/128 08:00:20:78:30:f9 1 REACHABLE le0#v6 ff02::1:2078:30f9/128 33:33:20:78:30:f9 1 REACHABLE Q. analyze the addresses on the four lines; Q y given that lrcsun13’s IPv4 address is 128.178.156.38 and lrcsun13’s MAC address is 08-00-20-78-30-F9 solution solution 11 11
IPv6 Host Configuration Example Output of "netstat ‐q" at lrcsun12 ; Interface Destination/Mask Phys Addr Ref State --------- ------------------- ---------- ------- --------------- le0#v6 ff02::2/128 33:33:00:00:00:02 1 REACHABLE le0#v6 ff02::1:80b2:9c26/128 33:33:80:b2:9c:26 1 REACHABLE le0#v6 fe80::1:0:800:2078:30f9/128 08:00:20:78:30:f9 1 REACHABLE le0#v6 ff02::1:2078:30f9/128 33:33:20:78:30:f9 1 REACHABLE Q. analyze the addresses on the four lines; given that lrcsun13’s IPv4 address is 128.178.156.38 and lrcsun13’s MAC address is 08-00-20-78-30-F9 A. ff02::2/128 33:33:00:00:00:02 all routers on link ff02::1:80b2:9c26/128 33:33:80:b2:9c:26 snmc addr of ::128.178.156.38 (special multicast address) fe80::1:0:800:2078:30f9/128 08:00:20:78:30:f9 link local of lrcsun13 ff02::1:2078:30f9/128 33:33:20:78:30:f9 snmc addr of above / Comment: could have been present: 4800::1:0:800:2078:30f9/128 08:00:20:78:30:f9 configured addr of lrcsun13 back 12 12
Issues with use of MAC address inside IPv6 Address Source: ipv6-g6-tutorial.pdf by Mohsen.Souissi@nic.fr 13 13
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