IPv6 Addressing

1
IPv6 Addressing

• OCCAID IPv6 Public Workshop Meeting
• Weehawken, NJ
• 17-22 October 2003

2
Agenda

• Evolution of IPv6
• Types of IPv6 addresses
• Work-in-progress
• OCCAID/T.Bone IPv6 addressing
• Please feel free to ask questions at any time!

3
Evolution of IPv6

• IPv4 address space running out
• Cant 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)

4
Types 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

5
Representation 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

6
Examples of Writing Addresses

• 20010470011200ed0000000000000001
• can be written
• 2001470112ed0001
• or
• 2001470112ed1

7
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

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Types 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

9
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?

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Types of Unicast Addresses

• Mapped IPv4 addresses
• Of form FFFFa.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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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)

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Types of Unicast Addresses

• Aggregatable global unicast address

13
Top-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)

14
OCCAIDs 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 6bones
  experimental 3ffe addresses.

15
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

16
Other Unicast Addresses

• Original provider-based
• Original geographic-based
• GSE (88)
• Hains Internet Draft for provider-independent
  (geographically-based) addressing

17
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

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

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OCCAID IPv6 Addressing

• Currently using the two /48s for member
  allocations
• 3ffe4010a00e/48 on 6bone
• 2001470112/48 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 /40s from our
  upstream transit and peering providers.
• If you need a /48 at your site, let us know!

20
OCCAID IPv6 Addressing

• TBONE backbone routers still running from old
  legacy HE.net TunnelBroker prefixes
• 20014701F00758/64 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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Allocation 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 members 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 OSes. For now
  we will stick with our current method Use /126.
• 2001470112FFFF5F0/80 San Francisco
  GigaPOP
• 2001470112FFFFB05/80 Boston and New
  England
• 2001470112FFFFDFE/80 Dallas Fortworth and
  Northern Texas
• 2001470112FFFF1AA/80 Houston GigaPOP
• 2001470112FFFF15A/80 NYC GigaPOP 1
• 2001470112FFFF747/80 NJ and NYC GigaPOPs
• 2001470112FFFFED0/80 NJ Newark GigaPOP
  and CNACS regions.
• 2001470112FFFF1AD/80 Washington D.C. and
  Virgnia
• 2001470112FFFF0ED/80 Chicago and
  Middle-of-nowhere states ? (e.g. Minnesota,
  Montana, et al)
• And so on.

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Allocation 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_at_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 dont support IPv6 on TNRA registry
  yet.

23
Obtaining Addresses and IPv6 Internet Access
through OCCAID

• Drop a note to CNACS list (occaid_at_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.