Expanding the IPv6 Lab Use Space

Introduction The address architecture for IPv6 does not explicitly define any prefixes allocated exclusively for lab use, nor is such address space allocated in or in . While lab deployments could potentially use IPv6 address prefixes typically assigned and configured in non-lab network, the use of such addressing in lab environments may create addressing conflicts and unnecessary operational confusion. For instance, designing labs utilizing ULA fc00::/7 is problematic due to the random global ID requirement preventing hierarchical network prefix design possibilities. Further, default address selection behavior by end nodes may result in a de-preference of such addresses and prevent lab deployments from accurately modeling their desired non-lab equivalents, especially in the testing of devices that are incapable of adjusting the global source selection table. To resolve these problems involved in building large-scale lab networks, and pre-staging, or automating large-scale networks for deployment, this document allocates the IPv6 address prefix 0200::/7 for these purposes. The goal is to allow organization to share working lab configuration files (with little or no need of modification) to be deployed in a third party lab environment, public and private externally managed services, virtualization or hosting environments as well as in other networks such as Service Providers, Enterprise, Government, IoT, and Energy, all with the knowledge that the lab GUA address space will perform the same as any GUA but with the added knowledge that filtering will be used to protect accidental leaks to the Internet. The following criteria is for selecting the lab prefix: Address space should reside outside of IANA allocated GUA block of 2000::/3 The precedence for the lab prefix should not be lower than the GUA prefix as defined in (unlike ULA). Reduce the operational impacts to IANA and the RIR's in selecting lab prefix space.

Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

Assignment of address space for use in large-scale lab and prototyping environments The prefix reserved for large scale lab and testing purposes is 0200::/7.

Operational Implications This space SHOULD NOT be employed for addressing use cases which are already defined in other RFCs, such as addresses set apart for documentation, testing, etc. Enterprise and large-scale networks have some specific criteria around building and validating prior to deployment. The issues with ULA for infrastructure modeling, lab creation, configuration and behavior testing at the host level are notably impactful in large enterprises as well as continental and global scale networks. This is primarily, but not exclusively, due to the increased focus on large-scale hosts, servers, and application testing. Additionally, it is likely that both GUA and ULA may co-exist or are planned to co-exist, and reconfiguring lab hosts, network elements, operational technology systems, and IoT hardware isn't practical or desirable due to inconsistent results for host preference due to behavior. Most large-scale enterprises strive to build lab, dev, and QA environments that reflect production as accurately as possible. This is a fairly straightforward way to avoid disparity between production and non-production. Enterprise environments are an area that need increased IPv6 adoption. In an effort to enable a more approachable mechanism to model a global scale network, and to avoid the pitfalls of ULA de-preferenced host behavior or mis-use (i.e. address space squatting) on other IPv6 space, a specific IPv6 lab prefix is being assigned.

Resource utilization The prefix in question, (0200::/7) has previously been used for the OSI NSAP-mapped prefix set in and , and deprecated, this address prefix is already limited in its usability and has not been officially re-purposed. The address prefix was returned to IANA and is available to be marked for other purposes. This assignment implies that IPv6 network operators SHOULD add this address prefix to the list of non-routable IPv6 address space, and if packet filters are deployed, then this address prefix SHOULD be added to packet filters. This is not a local-use address prefix so these filters may be used in both local and public contexts. As noted here by the IANA Internet Protocol Version 6 Address Space allocation reference, 0200::/7 was deprecated as of December 2004 by . This space is outside of the 2000::/3 address block, making it significantly easier to filter and providing straightforward visual and programmatic identification. Because the resource has been previously allocated, no new resources are required. Additionally, as noted by the IANA allocation list, approximately 85% of the IPv6 address space is reserved for future definition and use, and is not assigned by IANA at this time, leaving ample room for growth over the coming decades.

Acknowledgements The authors would like to acknowledge the valuable input and contributions of the v6ops WG. The authors further acknowledge the work of Bob Hinden and Stephen Deering, in authoring the protocol standard and the addressing architecture for IPv6. The authors would also like to recognize the valuable input, suggestions, and insight by Tom Coffeen, Scott Hogg, and Jay Stewart.

Security Considerations The addresses assigned for lab and staging use SHOULD be filtered as noted above. Setting aside address space for lab and staging use, and adding this address space to common filters to prevent destinations in this space from being routed in production networks (including the global Internet) improves security by preventing the leakage of prefixes used for testing into production environments. As such, setting aside this space improves the overall security posture of the Internet.

IANA Considerations IANA to allocate and record the reservation of the IPv6 global unicast address prefix 0200::/7 as a lab-only prefix in the IPv6 address registry. No end party is to be assigned this address.

Appendix A.