Subject: RE: Sub-optimal Terminology (was Re: [nemo]Re: I-D ACTION:draft-ietf-nemo-ro-problem-statement-01.txt)

From: "Pascal Thubert \(pthubert\)" <[email-masked]>
Date: Tue, 8 Nov 2005 17:27:05 +0100

>-----Original Message-----
>From: Christophe Janneteau [mailto:[email-masked]]
>Sent: Tuesday, November 08, 2005 5:08 PM
>To: Pascal Thubert (pthubert)
>Cc: Alexandru Petrescu; Masafumi Watari; IETF NEMO WG; T.J. Kniveton
>Subject: Re: Sub-optimal Terminology (was Re: [nemo]Re: I-D
ACTION:draft-ietf-nemo-ro-problem-
>statement-01.txt)
>
>
>Pascal Thubert (pthubert) wrote:
>> There is a topological view, where pinball routing and multi-angular
are
>> contenders, and there is a tunnel view, for which we'd need a term
like
>> telescopic or something. Any idea?
>>
>
>Hi,
>
>Is the term "nested tunnels" not the one we used to use?
[<PT>] Yes, it is. 

But that term, like suboptimal, is very generic. 

Now we are considering RO and finding more specific terms which would be
more uniquely associated to our problem would be nice, but if we don't,
I agree we have a default.

It could be also useful to distinguish when one side ends multiple
layers of tunneling, like a HA does if you form a nested structure of
MRs that depend on that same HA.

Any idea?

Pascal

---

From: Thierry Ernst <[email-masked]>
Date: Thu, 17 Nov 2005 18:51:34 +0900

My take on this issue:

1. I would like to add the agreed term in draft terminology. I've added
an issue A28, see http://www.sfc.wide.ad.jp/~ernst/nemo/

2. Several terms have been listed and here is my summary:

- sub-optimal routing: very generic
- triangular / dog-leg routing: very specific (MIP6 scenario)
- multi-angular
- pin-ball routing is inappropriate
- telescopic: why not periscope ? ;-)
- nested-tunnel

I think that:
- if no term is required to describe what happen in a nested NEMO, we
should stick to something generic i.e. "sub-optimal routing". If we what
something in line with the term usually used in MIP6 scenario
(triangular), I would vote for "multi-angular". If we need something
that doesn't describe what happens to the route, but rather to the
tunnel inefficiencies, I would vote for "nested tunnel".

On the overall, I would vote for "multi-angular" and if needed I would
add a 2nd term "nested tunnels". 

For a 1st April RFC, I would vote for "Periscope" ;-)
Thierry.

On Tue, 8 Nov 2005 17:27:05 +0100
"Pascal Thubert \(pthubert\)" <[email-masked]> wrote:

> Now we are considering RO and finding more specific terms which would
> be more uniquely associated to our problem would be nice, but if we
> don't, I agree we have a default.
>

---

From: Christophe Janneteau <[email-masked]>
Date: Thu, 17 Nov 2005 11:17:25 +0100

I agree with Thierry.

We can always use the term sub-optimal routing whenever needed.

But it also makes sense to have more specific terms for characterizing
the sub-optimality:

o for routing: I vote for "multi-angular", which makes more sense to me
than the dog-leg, pin-ball, or telescopic terms etc...

o for the tunnels: "nested tunnels" has my vote.

BTW, I think those two terms have been already used by many people in
the past, and we (NEMO community) somehow get used to them now :)

Christophe.

---

From: Chan-Wah Ng <[email-masked]>
Date: Thu, 17 Nov 2005 19:29:23 +0800

> - pin-ball routing is inappropriate

Why is pinball routing inappropriate?  I thought it draw a very vivid
picture of the routing phenomenon quite well.

> - telescopic: why not periscope ? ;-)

I don't think telescopic is appropriate, since not all telescopes have
multiple cylinders that can be nested within one another.  I think
nested tunnel is good enough.  And I don't think we need a term to
specifically differentiate the case of nested tunnels where the tunnel
end points are all different as opposed to when some of tunnel
end-points are the same node.

/rgds
/cwng

> For a 1st April RFC, I would vote for "Periscope" ;-)

:)

---

From: Henrik Levkowetz <[email-masked]>
Date: Thu, 17 Nov 2005 13:52:04 +0100

on 2005-11-17 10:51 Thierry Ernst said the following:
> should stick to something generic i.e. "sub-optimal routing".

Sounds good.

> If we what

Multi-angular already exists as a word, used in the sense "Viewed
from multiple angles (directions)".  You shouldn't use that one here.

I actually like "pin-ball route" (rather than routing) - it is
nicely colourful, and quite descriptive -- unless it's already
used in a conflicting sense in other RFCs.

As alternatives for your consideration, what about:
  * Nested triangular
  * Nested dog-leg
  * Compound triangular
  * Compound dog-leg

> For a 1st April RFC, I would vote for "Periscope" ;-)

Waiting to read that one :-)

	Henrik

---

From: Alexandru Petrescu <[email-masked]>
Date: Fri, 18 Nov 2005 19:34:05 +0100

Henrik Levkowetz wrote:
> from multiple angles (directions)".

Oh, I didn't know that.

> I actually like "pin-ball route" (rather than routing) - it is nicely
> colourful, and quite descriptive -- unless it's already used in a
> conflicting sense in other RFCs.

"internet pinball machine" in Internet Monthly Report 8912, yr1989, for
SNTP.  An MR with SNTP syncing cache at HAs may "pinball" among strata.

Otherwise no "pinball" nor "pin-ball" in RFCs; but often used in casual
routing discussions, not necessarily NEMO.

Google finds many hits for "pinball routing" in NEMO texts, so it could
be considered an established term as well.

> As alternatives for your consideration, what about: * Nested
> triangular * Nested dog-leg * Compound triangular * Compound dog-leg

"dog-leg" can have only three segments (bones).

zigzag.

I'm fine with any in the end.

Alex

---

From: Henrik Levkowetz <[email-masked]>
Date: Fri, 18 Nov 2005 19:51:23 +0100

on 2005-11-18 19:34 Alexandru Petrescu said the following:
[...]
> be considered an established term as well.

Ah, Ok.

> "dog-leg" can have only three segments (bones).

Yes.  But in nested dog-legs you may have one bone contain a dog-leg?

(I don't like this a lot myself, though...)

> zigzag.

That's pretty good.  I like that.

	Henrik

---

From: Thierry Ernst <[email-masked]>
Date: Mon, 21 Nov 2005 12:04:58 +0900

> > > from multiple angles (directions)".

That's not an IETF definition, so I don't see the point to stick to it.
Otherwise, how would you define triangular ? "Viewed from tri angles
(directions)" ? My point was that since "triangular" is used to describe
the MIP6 problem, it makes "multiangular" a good term to describe the
NEMO term. 

The other proposed term are "exotic" from the perspective of consistency
with older terms used in the mobility literature.

> > Google finds many hits for "pinball routing" in NEMO texts, so it
> > could be considered an established term as well.
> 
> Ah, Ok.

Definition ?

> > "dog-leg" can have only three segments (bones).

Yes, and besides this is really not a nice term, IMHO.

> That's pretty good.  I like that.

With what definition ? I prefer pinball because there is a long history
of using it. 

Thierry.

---

From: Henrik Levkowetz <[email-masked]>
Date: Mon, 21 Nov 2005 10:30:43 +0100

> the MIP6 problem, it makes "multiangular" a good term to describe the

No!

Triangular _does not_ mean viewed from 3 angles, it means having 3 line
joins (corners); but multi-angular _does_ mean viewed from multiple angles.
Never underestimate the idiosyncrasies of the English language ;-)

If you use this, you are going to confuse people needlessly.

> With what definition ? I prefer pinball because there is a long history

"Pinball route" works for me.

	Henrik

---

From: Chan-Wah Ng <[email-masked]>
Date: Mon, 21 Nov 2005 19:42:00 +0800

> > > could be considered an established term as well.

My attempt at one, to close this promptly:

        A pinball route refers to the non-direct path taken by packets
        sent between a MNN and a CN which is routed through one on more
        home agents.
        
If necessary, the following sentence may be appended to add more flavor:

        A packet following a pinball route would appear like a ball
        bouncing off one or more home agents before reaching its final
        destination.
        
/rgds
/cwng