Robert,
We may be converging!
In another email thread, you and I agreed that a SID should be drawn from
global unicast address space or ULA space, but not from any other special
address space (e.g., link-local, multicast). It would be great if that
agreement were reflected in the document.
We should also consider the consequences of sending packets with SIDs as source
addresses. In particular, we should consider the consequences of sending an
ICMP message with a SID in the source address field.
Another restriction may be required here.
Ron
From: Robert Raszuk <rob...@raszuk.net>
Sent: Friday, December 27, 2019 12:05 PM
To: Ron Bonica <rbon...@juniper.net>
Cc: SPRING WG <spring@ietf.org>
Subject: Re: [spring] 64-bit locators
Hi Ron,
Great to hear an agreement from you ! Must be power of Christmas :).
I actually see no conflict in the claim that SID is not an address in itself
with statement that it can be a routable entity which was I believe the
original intention of the text you quote.
I think your conclusion that we are both wrong based on section 2 of RFC8402
sits at the fact that the term "address" is rather broad and used (as already
proven in other messages) imprecisely or loosely all over IETF.
It is just like router_id ... it is a numerical representation of a node while
the moment you put this numeric 32 bit string under logical interface and
advertise it - it suddenly becomes a valid destination target or for that
matter src originator.
So to your first question ... I think we agreed in the other mail from which
spaces the IPv6 locator can be used. Of course as things evolve making any
assumption that such binding is going to stay intact would be rather weak
advice to any hardware designer.
To your second point I think SID itself when mapped to interface can be a src.
I see really nothing which could prevent me to use any address as src or dst in
my network.
I am actually not sure where are you going with those if you will
"restrictions" as to the SID semantical components. To me SID is a locally
significant value in the network (including overlay network) which chooses to
use SRv6 and I really see no reason to constrain it in any additional way.
Perhaps your point is that SID does not fit to RFC4291 IPv6 Addressing
Architecture. Well perhaps but if so RFC8402 should be listed in 4291 as
updating it - just like 5952, 6052, 7136, 7346, 7371, 8064 all do. Frankly I am
not sure why it is not there now in the first place.
Kind regards,
Robert.
On Fri, Dec 27, 2019 at 4:21 PM Ron Bonica
<rbon...@juniper.net<mailto:rbon...@juniper.net>> wrote:
Robert,
Personally, I agree with what you say below. “A SID is NOT an IPv6 address.”
However, Section 2 of RFC 8402 says that we are both wrong. It defines an SRv6
SID as follows:
“SRv6 SID: an IPv6 address explicitly associated with the segment.”
So, assuming that a SID is an IPv6 address, we must figure out how it fits into
the IPv6 addressing architecture. Questions like the following must be answered:
* From which special purpose prefixes [RFC 6890] can SIDs be drawn?
* Can a SID appear in the source address field of an IPv6 packet?
So far, the co-authors have avoided such issues.
Ron
From: Robert Raszuk <rob...@raszuk.net<mailto:rob...@raszuk.net>>
Sent: Saturday, December 21, 2019 6:43 PM
To: Ron Bonica <rbon...@juniper.net<mailto:rbon...@juniper.net>>
Cc: Andrew Alston
<andrew.als...@liquidtelecom.com<mailto:andrew.als...@liquidtelecom.com>>;
Alexandre Petrescu
<alexandre.petre...@gmail.com<mailto:alexandre.petre...@gmail.com>>; SPRING WG
<spring@ietf.org<mailto:spring@ietf.org>>; Gyan Mishra
<hayabusa...@gmail.com<mailto:hayabusa...@gmail.com>>; Pablo Camarillo
(pcamaril) <pcama...@cisco.com<mailto:pcama...@cisco.com>>; Mark Smith
<markzzzsm...@gmail.com<mailto:markzzzsm...@gmail.com>>
Subject: Re: [spring] 64-bit locators
Hey Ron,
> Leaving both chickens and eggs in the hen house……..
Indeed ... after all it is not Easter Time !
> Only one answer can be correct 😉
To me this is very obvious ...
SID is NOT an IPv6 address. Part of the SID is a locator which is used for
vanilla IPv6 forwarding (based on IPv6 routing prefixes), but that is all this
128 bit string has in common with IPv6.
Merry SID-less Christmas,
R.
On Sat, Dec 21, 2019 at 9:32 PM Ron Bonica
<rbon...@juniper.net<mailto:rbon...@juniper.net>> wrote:
Robert,
Leaving both chickens and eggs in the hen house……..
We have never explicitly stated whether a SID *is* and IPv6 address or *merely
resembles* an IPv6 address. Which is it?
Hint: This is a multiple choice question. Only one answer can be correct 😉
Happy Holidays,
Ron
Juniper Business Use Only
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