Re: [v6ops] IA_PD bit in RA

["STARK, BARBARA H" <[e-mail]>]

> But how about when the Delegated Prefix is available, but via 'other other'
> means than DHCP such as Radius, or via PPP?  There is no bit for that either.
> The 'O' and 'M' bits apply only to DHCP.

PPP is at a lower layer than IP. PPP clients are specifically configured to establish PPP (with PPP login and password). Once PPP is established, the client can try to establish IPv6 per RFC5072. This uses IPV6CP to negotiate the interface identifier of the client's WAN interface, which can then be used to construct the IPv6 Link-local address of this interface.

RFC7084 references that PPP may be established below IP (WLL-2, WLL-3). Once that link-local address exists on the PPP link, the RFC7084-compliant CE router sets up the rest of IPv6 exactly as it does for IPv6 directly over Ethernet (with RS/RA [though it's ok for there to be no RA since default route is the PPP link; but try it anyway in case there's a SLAAC prefix], DHCPv6). This is also consistent with BBF TR-124. The goal was to minimize the number of different ways of doing the same thing that would need to be coded in a CE router.

I can't address networks that might do RADIUS directly from the CE router, because I'm not familiar with any such networks. BBF TR-177 and TR-187 do support using RADIUS in the access network, but the CE router doesn't know this. The access network can pick up the CE router's authentication parameters from access line identification information in the RS (inserted by the access node, and not the CE router) or from PPP. Since the CE router has no concept of RADIUS, it's not possible for it to do something different in response to RADIUS. I'd like to keep it this way.

I think it's very good that there are no special RA bits for PPP or RADIUS.
Barbara