Re: [spring] 64-bit locators

[Robert Raszuk <[e-mail]>]

Hi Mark,

Happy New Year !


> The key point is that RIDs look like IPv4 addresses, but are not. They
> only have adopted the formatting convention of IPv4 addresses. They're 32
> bit quantities. They could have just as easily been formatted as 0x hex
> strings e.g. 0xffffffff for my example. Their continued use as 32 bit
> quantities and identifiers in IPv6 supporting OSPFv3 shows how decoupled
> from both IPv4 and IPv6 they are.
>

We are again in 100% agreement here. That was exactly my analogy to RID
made to Ron. But on the other hand let's also recognize that this is pretty
common to assign router_id to be yr loopback address in number of
protocols.


> SIDs on the other hand are at some point in time used as IPv6 destination
> addresses.
>

Well SID locators (of variable length) need to assure packet delivery to a
segment end points. That is a subtle but very important difference.


> That means they have to either always comply with IPv6 address
> requirements - RFC4291 - or be converted to meet IPv6 address requirements
> when they're used as IPv6 addresses (e.g. they're 64 bit quantities that
> are then used as an IPv6 Interface Identifier by prepending an IPv6
> addressing compliant /64 prefix)
>

IPv6 address fields are 128 bits (for good or for bad of it). And there are
no :: or : there to the point Alex made earlier. What matters is to make
sure that routing prefixes deliver packets to correct destinations.

I am very puzzled reading those messages what is the point regarding all
remaining bits outside of locator ? If this is to say RFC4291 did not
defined a SID - sure you won - game over. But at the same time I do not see
anything in RFC4291 which would prohibit me to put any bit sequence I like
in the remaining (least significant) bits of the address. And I think this
is the crux of the little discussion here.

Cheers,
R.