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Issue D efinition*: 6RD and IPv6 allocation policy

Issue D efinition*: 6RD and IPv6 allocation policy. Jan Žorž (Go6 Institute Slo ) Mark Townsley (Cisco). *Or, Why we had to wake up on Friday to be here?. Aspects of IPv6 Transition Mechanisms. Tunnel or Translate Stateless or Stateful

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Issue D efinition*: 6RD and IPv6 allocation policy

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  1. Issue Definition*:6RD and IPv6 allocation policy Jan Žorž (Go6 Institute Slo) Mark Townsley (Cisco) *Or, Why we had to wake up on Friday to be here?

  2. Aspects of IPv6 Transition Mechanisms Tunnel or Translate Stateless or Stateful SP-Managed or not SP-Managed 6rd is a Stateless, SP-Managed, Tunneling Protocol

  3. IPv6 Prefix from an IPv4 Address • The following construction is what allows 6rd to beSP-managed and Stateless ISP 6rd IPv6 Prefix Subscriber IPv4 address Subnet-ID 198.51.100.1 2001:db8 64 /n /m 0 Interface ID Subscriber Delegated IPv6 Prefix

  4. 6rd – Encapsulation and Packet Flow “…externally 6rd looks, feels and smells like native IPv6 ” – RIPE Labs 6rd 6rd Dual Stack IPv4 Dual Stack Dual Stack Dual Stack 6rd Border Relays CE IPv4-only Access Network • IPv6 in IPv4 (protocol 41) encapsulation • Within a domain, IPv6 traffic follows IPv4 routing • CEs reach BRs via IPv4 anycast

  5. 6rd – CE Provisioning 6rd 6rd Dual Stack IPv4 Dual Stack Dual Stack Dual Stack 6rd Border Relays CE • Each 6rd CE within a 6rd Domain requires a single DHCP option* carrying 4 values 6rdPrefix 6rdPrefixLen IPv4MaskLen 6rdBRIPv4Address • These 4 values are the same for all CEs within the domain *May also be configured with TR-69 or otherwise

  6. 6rd – Deployments 6rd 6rd Dual Stack IPv4 Dual Stack Dual Stack Dual Stack 6rd Border Relays CE • Defined in RFC 5969 • Commercially available products from a number of vendors • First deployment in 2007, multiple deployments today

  7. Q: What should /n and /m be? ISP 6rd Prefix IPv4 (0-32 bits) Subnet-ID 198.51.100.1 2001:db8 Interface ID 64 /m /n 0

  8. Starting simple: /n = 28, /m = 60 ISP 6rdIPv6 Prefix 32 bits Interface ID Subnet-ID 198.51.100.1 2001:db8 64 /60 /28 0 • One 6rd domain • 6rd provisioning is identical for all CEs • Convenient conversion between subscriber IPv6 and IPv4 address • Allows 16 IPv6 subnets in the home • ISP needs a /27 or shorter

  9. But what if you cannot get a /27?/n = 32, /m = 64 ISP 6rdIPv6 Prefix 32 bits Interface ID 2001:db8 198.51.100.1 /32 /64 0 • Still a single domain, but/64 does not allow multiple subnets for the subscriber • No subnets, no routing • Common features such as Guest + Home SSIDs become very difficult • Support for 802.15.4 for Sensors, Zigbee, etc. • Ultimately leads to IPv6 NAT

  10. Using less than 32 bits of IPv4 • If the IPv4 space is an aggregate, 6rd need not carry the common bits • For example, in a CGN world of 10/8, we just don’t carry around the 10 24 bits Subnet-ID .51.100.1 .51.100.1 2001:db8 2001:db80:0 64 64 /60 /56 /36 /32 0 0 Interface ID Interface ID

  11. Multiple 6rd Domains ISP 6rdIPv6 Prefix Distinct IPv4 Aggregates 32 bits 4 bits 8 bits Interface ID (64 bits) 20 bits IPv4 /12 8 bits Interface ID (64 bits) 16 bits 32 bits 8 bits IPv4 /16 8 bits Interface ID (64 bits) 18 bits 32 bits 4 bits IPv4 /14 8 bits Interface ID (64 bits) 19 bits 32 bits 3 bits IPv4 /11 • More efficient in terms of IPv6 space usage • However, CEsin different domains require different configuration • Operations begin to get more complicated, traffic patterns not as efficient, etc.

  12. How do I get my /27? • /27 yields /60 for the home • /29 yields /62 for the home

  13. Possible solutions • Declare this is a non-problem • Special 6rd policy. e.g., /27 granted based on ability and intention to deploy more rapidly with 6rd • Allow /29 to anyone • Others?

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