IPv6 Addressing

OCCAID IPv6 Public Workshop Meeting

Weehawken, NJ

17-22 October 2003

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Click to edit Master title styleAgenda

Evolution of IPv6

Types of IPv6 addresses

Work-in-progress

OCCAID/T.Bone IPv6 addressing

Please feel free to ask questions at any time!

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Click to edit Master title styleEvolution of IPv6

IPv4 address space running out• Can’t get needed addresses (particularly outside Americas)

• Resort to private (RFC1918) addresses and NAT.

Competing plans to address problem• Some 64-bit, some 128-bit

Current scheme unveiled at Toronto IETF (July 1994)

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Click to edit Master title styleTypes of IPv6 Addresses

No different than IPv4…

(With exception of “crazy-looking” IP addresses)

• Unicast• Multicast• Anycast

…but designed into specifications from the beginning, where as IPv4 did not.

…also includes standards for addressing plans…

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Click to edit Master title styleRepresentation of Addresses

All addresses are 128 bits

Eight octets in IPv6, instead of four in IPv4:

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

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Click to edit Master title styleExamples of Writing Addresses

2001:0470:0112:00ed:0000:0000:0000:0001

can be written

2001:470:112:ed:0:0:0:1

or

2001:470:112:ed::1

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Click to edit Master title styleInterface 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

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Click to edit Master title styleTypes of Unicast Addresses

Unspecified address• All zeros (::)• Used as source address during initialization• Also used in representing default route

Loopback address• Low-order one bit (::1)• Same as 127.0.0.1 in IPv4

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Click to edit Master title styleTypes 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?

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Click to edit Master title styleTypes 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

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Click to edit Master title styleTypes 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)

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Click to edit Master title styleTypes of Unicast Addresses

Aggregatable global unicast address

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Click to edit Master title styleTop-Level Aggregators

Allocated by RIRs to transit providers

In practice, RIRs have adopted “slow-start” strategy

• Started by allocating /35s• Expanded to /32s after sufficient use in /35• Eventually move to /16s• Allocation fees waived by most RIRs for ISPs with existing RIR membership. (e.g. ARIN)

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Click to edit Master title styleOCCAID’s IPv6 Setup

- Started out with /64 site prefixes from Hurricane Electric TunnelBroker to quickly number backbone router addresses and bring the network online in short timeframe. (The entire OCCAID backbone network went IPv6-capable in just under a week)

- Currently classified as “pNLA” transit network according to 6bone policies.

- Currently receives multiple /40 and /48 prefixes from upstream transit providers and peering parties.

- Application of /32 sub-TLA from the RIR (ARIN in our region) is in the plans.

- We will not request “pTLA” space out of 3ffe::/16 from 6bone. It is already too late for 6bone’s experimental 3ffe:: addresses.

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Click to edit Master title styleNLAs 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

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Click to edit Master title styleOther Unicast Addresses

Original provider-based

Original geographic-based

GSE (8+8)

Hain’s Internet Draft for provider-independent (geographically-based) addressing

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Click to edit Master title styleMulticast 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

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Click to edit Master title styleAnycast 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

Setting up IPv6 anycast is not very different than in IPv4 anycast. Small set of differences thus far.

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Click to edit Master title styleOCCAID IPv6 Addressing

Currently using the two /48’s for member allocations:

• 3ffe:4010:a00e::/48 on 6bone• 2001:470:112::/48 on production

Planning migration from 6bone addressing

Currently handing off /60 and /64 prefixes to downstream members.

- Plan is to apply for /32 sTLA from ARIN and begin handing off /40 and /48 prefixes to downstream members.

- We can request more /48 and /40’s from our upstream transit and peering providers.

- If you need a /48 at your site, let us know!

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Click to edit Master title styleOCCAID IPv6 Addressing

TBONE backbone routers still running from old legacy HE.net TunnelBroker prefixes:

• 2001:470:1F00:758::/64 on backbone router interfaces. Explains why you see HE.net TunnelBroker address space when running traceroute6 to an OCCAID downstream member site.

Planning migration from TunnelBroker prefixes to our own sTLA once we have it.

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Click to edit Master title styleAllocation Procedures

POPs allocated /80s for point-to-point links between downstream member and the backbone router. We use /126 subnet over a point-to-point link that hands off connectivity from our backbone router to member’s site.

• No BCP (yet) for point-to-point allocation procedures. Discussions still happening at IETF. Current standard is to use /64 subnet over a point-to-point link, but many people use /127. A lot of people say /127 presents problems with buggy IPv6 implementations in some OS’es. For now we will stick with our current method: Use /126.

• 2001:470:112:FFFF:5F0::/80 – San Francisco GigaPOP• 2001:470:112:FFFF:B05::/80 – Boston and New England• 2001:470:112:FFFF:DFE::/80 – Dallas Fortworth and Northern Texas• 2001:470:112:FFFF:1AA::/80 – Houston GigaPOP• 2001:470:112:FFFF:15A::/80 – NYC GigaPOP 1• 2001:470:112:FFFF:747::/80 – NJ and NYC GigaPOPs• 2001:470:112:FFFF:ED0::/80 – NJ Newark GigaPOP and CNACS regions.• 2001:470:112:FFFF:1AD::/80 – Washington D.C. and Virgnia• 2001:470:112:FFFF:0ED::/80 – Chicago and Middle-of-nowhere states (e.g. Minnesota,

Montana, et al)• And so on….

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Click to edit Master title styleAllocation Procedures

Members allocated /64s in general.• Want more? Get more. Just ask!• As mentioned before, we will begin allocating /48s in

general to members once we obtain /32 sTLA space.• Many members also request /60 as well. Some so far have

requested /48s (In such case, we ask our upstreams to allocate us a /40 or shorter prefix).

• TowardEX handles all reverse DNS for delegated address space. E-mail hostmaster@towardex.com for DNS requests.

• TNRA routing registry must support IPv6 soon!– Will upgrade registry once Merit releases stable version of

IRRd that supports IPv6.– For now we don’t support IPv6 on TNRA registry yet.

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Click to edit Master title styleObtaining Addresses and IPv6 Internet Access through OCCAID

Drop a note to CNACS list (occaid@cnacs.occaid.org) with request.

Will also do BGP peering with anyone.

Thank you for joining! We will keep you posted for next meeting as soon as information is available.