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IPv6 Addressing. Internet2 IPv6 Workshop Research Triangle Park, NC 5-7 March 2002. Overview of Addressing. Historical aspects Types of IPv6 addresses Work-in-progress Abilene IPv6 addressing. Historical Aspects of IPv6. IPv4 address space not big enough
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IPv6 Addressing Internet2 IPv6 Workshop Research Triangle Park, NC 5-7 March 2002
Overview of Addressing • Historical aspects • Types of IPv6 addresses • Work-in-progress • Abilene IPv6 addressing
Historical Aspects of IPv6 • IPv4 address space not big enough • Can’t get needed addresses (particularly outside Americas) • Resort to private (RFC1918) addresses • Competing plans to address problem • Some 64-bit, some 128-bit • Current scheme unveiled at Toronto IETF (July 1994)
Types of IPv6 Addresses • Like IPv4… • Unicast • Multicast • Anycast • …but designed into specifications from the beginning
Representation of Addresses • All addresses are 128 bits • Write as sequence of eight sets of four hex digits (16 bits each) separated by colons • Leading zeros in group may be omitted • Contiguous all-zero groups may be replaced by “::” • Only one such group can be replaced
Examples of Writing Addresses • 3ffe:3700:0200:00ff:0000:0000:0000:0001 • can be written • 3ffe:3700:200:ff:0:0:0:1 • or • 3ffe:3700:200:ff::1
Interface Identifiers • Sixty-four bit field • Guaranteed unique on subnet • Essentially same as EUI-64 • Formula for mapping IEEE 802 MAC address into interface identifier • Used in many forms of unicast address
Types of Unicast Addresses • Unspecified address • All zeros (::) • Used as source address during initialization • Also used in representing default • Loopback address • Low-order one bit (::1) • Same as 127.0.0.1 in IPv4
Types of Unicast Addresses • Link-local address • Unique on a subnet • Result of router discovery or neighbor discovery • High-order: FE80::/64 • Low-order: interface identifier • Site-local address • Unique to a “site” • High-order: FEC0::/48 • Low-order: interface identifier • What is a site?
Types of Unicast Addresses • Mapped IPv4 addresses • Of form ::FFFF:a.b.c.d • Used by dual-stack machines to communicate over IPv4 using IPv6 addressing • Compatible IPv4 addresses • Of form ::a.b.c.d • Used by IPv6 hosts to communicate over automatic tunnels
Types of Unicast Addresses • Aggregatable global unicast address • Used in production IPv6 networks • Goal: minimize global routing table size • From range 2000::/3 • Three fields in /64 prefix • 16-bit Top Level Aggregator (TLA) • 8-bit reserved • 24-bit Next Level Aggregator (NLA) • 16-bit Site Level Aggregator (SLA)
Types of Unicast Addresses • Aggregatable global unicast address
Top-Level Aggregators • Allocated by RIRs to transit providers • In practice, RIRs have adopted “slow-start” strategy • Start by allocating /35s • Expand to /29s when sufficient use in /35 • Eventually move to /16s
Abilene sTLA • Allocated 2001:468::/35
NLAs and SLAs • NLAs used by providers for subnetting • Allocate blocks to customers • Can be multiple levels of hierarchy • SLAs used by customers for subnetting • Analogous to campus subnets • Also can be hierarchical
Other Unicast Addresses • Original provider-based • Original geographic-based • GSE (8+8) • Hain’s Internet Draft for provider-independent (geographically-based) addressing
Multicast Address • From FF00::/8 • Address contains four-bit scope field • Unlike IPv4 multicast, scope is explicitly defined in address • Low-order 112 bits are group identifier, not interface identifier
Anycast Address • Used to send packets to all interfaces on a network (like IPv4 anycast, not all will necessarily respond) • Low-order bits (typically 64 or more) are zero
Abilene IPv6 Addressing • Two prefixes allocated • 3ffe:3700::/24 on 6bone • 2001:468::/35 sTLA • Planning migration from 6bone addressing • Current addressing plan built on assumption of /35
Allocation Procedures • GigaPoPs allocated /40s • Expected to delegate to participants • No BCP (yet) for GigaPoP allocation procedures • Direct connectors allocated /48s • Will (for now) provide addresses to participants behind GigaPoPs which haven’t received IPv6 addresses • See WG web site for details
Registration Procedures • Providers allocated TLAs (or sTLAs) must register suballocations • ARIN allows rwhois or SWIP • For now, Abilene will use SWIP • Will eventually adopt rwhois • GigaPoPs must also maintain registries • Will probably have central Abilene registry
Obtaining Addresses • Drop a note to Abilene NOC (noc@abilene.iu.edu) with request • Will set wheels in motion