Re: Some Comments on ID/Loc Separation Proposals

[Dave Crocker <dhc@dcrocker.net>]

Margaret,


Wnc> The use of the term "Identifier" or "ID" sweeps an important
MWnc> issue under the rug in some cases:  Is this a host ID or an
MWnc> interface ID?

or a 'stack id' or an 'endpoint id'?  and what do these mean,
precisely.

so, yes, we need to be precise and consistent in defining the term.
(Our -analysis- paper has an increasing list of terminology, with a
goal of capturing consensus definitions.  Feedback is eagerly sought.)


MWnc>     - Initial end-to-end connection set-up.
MWnc>     - Referrals.
MWnc>     - What happens when two nodes try to establish connections
MWnc>       to each other "simultaneously"
MWnc>     - How does the mechanism avoid connection hijacking?

These are really good points.  For example, I had frankly been
avoiding trying to handle referrals, but any solution needs to attend
to this requirement explicitly.


MWnc> MAST Feedback:

MWnc> Uses a control protocol between the two end-nodes to 
MWnc> exchange address information.  The current proposal is
MWnc> two sparsely defined to allow a full analysis of its
MWnc> properties.

And, of course, that is intentional.  The intent is to distinguish
between basic approach, versus the essential details of a
specification that permits real implementation.


MWnc> In particular the document does not describe
MWnc> when MAST control messages would be sent, and how the
MWnc> nodes would know when to send them.

Right. Absolutely required -- eventually -- but not the rocket science
of designing an address pool maintenance mechanism.


MWnc>         - How do the end-points know when they need to
MWnc>           send SET operations to update the locators 
MWnc>           being used on the ends of this connection?

ignoring the heartbeat function that is suggested, why would not the
obvious "when something changes" rule suffice?


MWnc>         - The draft suggests using IPsec to secure the
MWnc>           control connection, but IPsec doesn't support
MWnc>           changing end-point addresses.

As one or another of the other wedge proposals suggests, IPSec would
run above the Mast address pool mechanism.  Hence, IPSec would only
see one "address".


MWnc>         - The PROBE message sounds (to me) similar to 
MWnc>           the old proposal to use pings to detect dead
MWnc>           gateways.  What can we learn from the problems
MWnc>           with that model that apply here?

I, too, would greatly like to hear feedback on this construct.  I've
seen a couple of comments that raised no concerns about it, but none
that offered assurance it would work ok.



d/
--
 Dave Crocker <dcrocker-at-brandenburg-dot-com>
 Brandenburg InternetWorking <www.brandenburg.com>
 Sunnyvale, CA  USA <tel:+1.408.246.8253>