Subject: [Softwires] draft-byrne-v6ops-clatip-01

From: Cb B <[email-masked]>
Date: Thu, 27 Mar 2014 10:58:14 -0700

Hi Softwires,

Ales presented draft-byrne-v6ops-clatip-01 in softwires at the last
IETF meeting.

I am attempting to have this I-D adopted by v6ops, but v6ops requested
feedback from softwires first.

Pertaining to the minutes, i would like to address some topics to make
sure it is ok  for v6ops to move forward with adoption

https://tools.ietf.org/wg/softwire/minutes?item=minutes-89-softwire.html

The addresses, both in DS-lite and 464xlat, never appears on the wire
so there is no chance of overlap or collision.  There is also no need
to expand the range from /29 to a /28.  Both DS-lite and 464XLAT only
emit IPv6 packets on the wire towards the network.

Are there other concerns that need to be brought up?  I believe it is
best to keep the existing /29, aim of this draft is to simply
generalize the description of the range in the IANA register.

Best regards,

Cameron

---

From: Dave Thaler <[email-masked]>
Date: Thu, 27 Mar 2014 22:38:49 +0000

> -----Original Message-----
> From: Softwires [mailto:[email-masked]] On Behalf Of Cb B
> Sent: Thursday, March 27, 2014 10:58 AM
> To: [email-masked]
> Subject: [Softwires] draft-byrne-v6ops-clatip-01
> 
> Hi Softwires,
> 
> Ales presented draft-byrne-v6ops-clatip-01 in softwires at the last IETF
> meeting.
> 
> Pertaining to the minutes, i would like to address some topics to make sure it
> is ok  for v6ops to move forward with adoption
> 
> The addresses, both in DS-lite and 464xlat, never appears on the wire so
> there is no chance of overlap or collision. 

Disagree, that conclusion doesn't follow (and in my experience it's wrong).
Overlap/collision happens when there are two interfaces on the same host
(even if they're not in use simultaneously).   The collisions can affect 
the routing table (if the host implements in such a way), ACLs like in 
host firewall policies and such, and various application-layer uses.

It's fine to specify use as the default range (e.g. for 464xlat or DS-lite) but
important to never constrain it to only that range, assuming the range is made
non-DS-lite specific.

-Dave

---

From: Cb B <[email-masked]>
Date: Sat, 29 Mar 2014 04:59:37 -0700

> host firewall policies and such, and various application-layer uses.

Ah, i see your point.  If the host is itself both a B4 and a CLAT at
the same time, then this collision may occur within the host, not on
the wire.

> important to never constrain it to only that range, assuming the range is made

Is there such a constraint that would cause a problem?

Looking at RFC6333 and draft-byrne-v6ops-clatip, i see that RFC6333
says the B4 SHOULD use 192.0.0.2.  To a rational person, a good reason
to not use  192.0.0.2 is that it is in use for a CLAT interface on the
same host, which fits with the SHOULD wording.

Is there some text that you could suggest that may clarify this
situation in draft-byrne-v6ops-clatip or is it ok for v6ops to adopt
as-is?  As it stands, the I-D simply says that 192.0.0.0/29 will be
generalized without making any further statements how addresses may be
used within that range.

CB