RJ Atkinson allegedly wrote: > Indeed, in the common case of an IEEE 802 LAN, the ID is used > in IPv6 ND as an opaque index into a layer-2 bridge table for > delivery within the final subnet. Other link types might behave > quite differently; I doubt that ND is in use with all link types. > > In any event, bridging is not forwarding. Even in the IEEE 802 > LAN case, one cannot even directly bridge on the Destination ID > (since the ID might be derived from something other than the MAC > address of the interface attached to the particular subnetwork > specified by the Destination Locator). So the ID really is > just an opaque table index, even in the IEEE 802 LAN case.
(First, please ignore the message I just sent -- I'm apparently still waking up.) I don't think I'm parsing this right, but in any case it's clear that the ID is used to determine the appropriate network attachment point to deliver the packet to. That is, the forwarding function is using the ID as input -- to "locate" the destination. That is quite different from HIP as an example. It's called an identifier because it does not determine topological location, but in this particular case -- delivering a packet -- the only function using this field is a forwarding function. In other cases, for example session control, identification functions might use it -- but they might choose to use completely different names, for example dynamically generated transient "identifiers". Would this still be an identifier if it were never used as one? There is no clear delineation here. Some tokens are used by forwarding on just the last hop. Some are used for the last few hops. Some are used by forwarding along the entire path. It is difficult to say that anything that appears in every packet is ever a pure "identifier" ... but I assert that you don't need to. Our goal is to support multihoming and mobility while simultaneously solving routing and addressing scaling problems. To do that we need to make it possible for identification functions to work independently of topological location. That doesn't mean that individual fields or names ever need to be exclusively used for identification, although some approaches do so -- just that they can be used for identification, independent of topology, when needed. _______________________________________________ rrg mailing list [email protected] https://www.irtf.org/mailman/listinfo/rrg
