On 05/19/2013 06:27 PM, james woodyatt wrote: >>> The Net_Iface is a value that identifies the network interface >>> for which an IPv6 address is being generated. The following >>> properties are desirable for the Net_Iface: >>> >>> o it MUST be constant across system bootstrap sequences and >>> other network events (e.g., bringing another interface up or >>> down) >>> >>> o it MUST be different for each network interface >>> >>> Some hosts have dynamic logical network interfaces >>> (distinguishable from physical interface), which are created >>> every time the host joins a network, and destroyed when the host >>> separates from a previously joined network. Examples are >>> typically interfaces that involve signaling systems, >>> point-to-point connection semantics for the link layer, e.g. >>> virtual private networks, automatic tunnels, et cetera. >>> >>> According to these requirements, such hosts MUST NOT reuse >>> previously generated stable privacy addresses when joining the >>> same network with a new logical interface. That seems counter to >>> the goal of this standard. >> >> I'm not sure I follow... The requirement is that you address >> changes when you move from one network to another. The only >> requirement for "Net_Iface" must be different for different network >> interface is that DAD failures are avoided (i.e., you don't have >> any two interfaces deterministically getting the same address). > > If avoiding DAD failure is the goal,
Yes. > then the second clause is overly > restrictive. It should suffice that the value of Net_Iface is > different for each network interface in *simultaneous* use. mm... how would you define simultaneous use? Is an interface that is down considered "in use"? If not, is the "Net_face" for that interface expeted to change (to comply with req #2) when the interface is brought up? >>> I think hosts need some latitude in these requirements to allow >>> for temporally different network interfaces associated with the >>> same network service from the host's view to have the same >>> identity for the purpose of generating stable privacy addresses. >> >> If you use the interface index for Net_Iface, you'd probably get >> exactly this. Same thing if you use the interface name (these >> virtual interfaces are likely to get the same names when they are >> re-created?). > > That's not the sort of assumption I want to see go unstated in a > Standards Track RFC. Better would be to avoid the ambiguity > altogether. For example, OS X does not have a requirement that > network interfaces have unique names. How do you ifconfig(8) them if the name is not unique? > There is a UUID that > identifies network services, which are related to the network > interfaces the system configuration service manages, but network > *services* on OS X are not the same as network *interfaces*, and they > are not mapped 1:1 to one another. I'm kind of lost here, sine I don't know the details behind OS X. Are you arguing tha the discussion of interfae names (or something else) is incorrect? Are you arguing that there's something that should be clarified? (if so, what, and how?) ANy help in this respect will be really welcome. Thanks! Best regards, -- Fernando Gont SI6 Networks e-mail: [email protected] PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492 -------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
