Hi, it seems that there is currently not much interest in ULA-Cs (centrally assigned ULAs). I came across several use cases, where manufacturers (e.g, those of cars, airplanes, or smart metering environments) would need internal/closed IPv6-based networks (maybe only for internal control and management), that have no connection to the Internet. For several reasons (esp. security) those networks should operate isolated and independent from the Internet. In some cases these products or installations may get merged, so prefix uniqueness would be beneficial. Using locally assigned ULAs still bears the risk of getting conflicts between manufacturers, esp. when considering the number of manufacturers and products.
On the one hand it would be preferable for manufacturers to have an own prefix for that purpose. Since every product with an on-board network would need such a unique prefix, getting/requesting /48 ULAs per product or installation doesn't seem to be appropriate. On the other hand the currently defined ULA format is probably also not very well-suited for that purpose, since it is intended to be used for sites, but these products rarely require ~2^16 subnets, i.e., an 8 bit subnet ID may be sufficient for most purposes. Thus, for this case the currently defined ULA format is too restrictive requiring a 16-bit subnet ID. Letting manufacturers ask for a large PI prefix from the normal routing space does not make much sense either, since it is not intended to be ever routed in the Internet. Wouldn't it make more sense to define something similar to existing ULAs along the lines of: | 7 bits | 21 bits | 36 bits | 64 bits | +--------+----------+--------------------+----------------------------+ | Prefix | OUID | OLA Prefix | Interface ID | +--------+----------+--------------------+----------------------------+ Prefix: fixed, TBA, e.g., fa00::/7 OUID: Centrally assigned organizational unique ID OLA Prefix: Organization locally assigned prefix, that consists of a Product specific prefix ID (PID) and an n-bit subnet ID, e.g.: | 7 bits | 21 bits | 36-n bits | n bits | 64 bits | +--------+----------+-----------+--------+----------------------------+ | Prefix | OUID | PID |SubnetID| Interface ID | +--------+----------+-----------+--------+----------------------------+ PID: Product specific prefix ID (should be unique across all products under the same OUID). Usually n=8 or larger, depending on the number of manufactured products (in this case 2^28=268,435,456) and their expected lifetimes. So the idea is to centrally assign the OUIDs and let the organizations assign the PID. If the OLA prefix space is too small for a manufacturer (some sell currently more than 10^7 units per year), he may request another OUID, just like it is done for company_ID/OUIs for IEEE-based addresses. Different sizes for OUID and the OLA prefix may be discussed (using 22 bits for OUID), but I just wanted to get input first whether this would be useful at all or why it may be definitely a bad idea (except that companies may misuse these addresses for other purposes). Regards, Roland -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------