Dear Colleagues, During the discussion on the APWG list about 6rd, several people have inquired about the exact way Registration Services evaluates requests for 6rd deployment. This email will try to answer these inquiries. The RIPE NCC considers current policy to be completely agnostic to 6rd, it neither specifically supports nor disallows 6rd deployment. This means that Registration Services will evaluate IPv6 allocation requests that include 6rd deployments according to the established policies and procedures of justified need. During the evaluation of an IPv6 allocation request the IPRA will look at the assignment size and the expected number of assignments to arrive at the size of the allocation that is justified. When an LIR wants to deploy 6rd by encoding the full 32 bits of the IPv4 addresses in the IPv6 end-user prefix, the allocation that would be needed is often much larger than would otherwise be justified using this principle as almost all of the reserved end-user prefixes would remain unused. Two examples with some numbers: An average size ISP has 1 million residential customers, intends to deploy 6rd and assign each end-user a /48. 1 million /48 end-site assignments would justify a /28, ignoring for the moment other requirements such as LIR infrastructure that might require more space. Deploying 6rd by encoding the full 32 bits of the IPv4 address would inflate the need to a /16. Currently, in this case, the IPRA would not consider allocating a /16 to be justified. Another LIR, who has 3 million customers, intends to deploy 6rd with / 60 assignments. Currently, the IPRA would consider 3 million /60 assignments to fit into a /38, thus the default /32, while the 6rd deployment would require a /28. Note that neither of these LIRs would qualify easily for an additional allocation under the HD-ratio rules. Best regards, Alex Le Heux RIPE NCC