Subject: [nemo] RO Taxonomy

From: Thierry Ernst <[email-masked]>
Date: Fri, 30 Jul 2004 19:59:56 +0900

Dear all,

I've beeen thinking for a while about a RO taxonomy. I think an
exhaustiv taxonomy would consider all potential solutions, included
MIP6-based solutions, but not limited to it. Since we don't have much
experience in NEMO topologies, it might be useful that the study covers
all host mobility approaches. 

As far as host mobility support is concerned, at least the following
classes would exist:

1. two-tier addressing category: using 2 addresses, one as a locator, one
   as a identifier

2. routing-based category (using routing protocols)

3. renumbering (changing the address/prefix)

4. combined (a combination of the above)

5. separation of locator and identifier

6. overlay network

7 others

Depending on how detailed the taxonomy is, these may be further be
divided into sub classes. For instance, the two-tier addressing category
could be divided into:

  -- home-agent based framework (e.g. MIP6)
  -- hierarchical framework (e.g. HMIP6)
  -- multicast framework
  -- others

Some solutions like HMIP would of course be ranged both into home-agent
based and hierarchical.

Each category has of course its limitations and benefits. Some may not
applied to NEMO, but it would be better to find out before we
investigate one specific category.

I've made such a taxonomy for host mobility support a couple of years
ago. 

I guess it could be applied to network mobility support, but would need
to be refined, because of the complexity of the configurations like
nested mobile networks, and the number of cases where RO is needed (e.g
between 2 nodes in distinct nested-NEMO). I don't even dare to mention
multihoming, but for this latter case, I'm pretty sure we would be well
inspired to follow the work done in the multi6 WG.

Might be useful to speak about this at SD.

Thierry.

---

From: Mattias Pettersson <[email-masked]>
Date: Fri, 30 Jul 2004 16:33:28 +0200

Hi Thierry,

> 5. separation of locator and identifier

I agree that this is useful, but I get the feeling some of them belong 
to other than the IP layer in the stack. Class 3, 5 and 6 would need 
support from upper layers to handle changing IP addresses without 
breaking applications' sessions.

Do we want to talk about classes of solutions belonging to any layer?

/Mattias

---

From: Alexandru Petrescu <[email-masked]>
Date: Fri, 30 Jul 2004 18:33:27 +0200

Thierry Ernst wrote:
>  experience in NEMO topologies, it might be useful that the study
> covers all host mobility approaches.
> 
> 1. two-tier addressing category: using 2 addresses, one as a locator,
> one as a identifier
[...]
> divided into sub classes. For instance, the two-tier addressing
> category could be divided into:
> 

1.5. using 2 addresses: one as an IP address, one as a FQDN name; also
      known as DNS updates.

> investigate one specific category.

But I think this is all about host mobility in general. What is specific
about RO in this taxonomy?

What is "multicast framework" and how does it provide RO for mobiles?

What is a "path length" anyways. Is the "path length" the number of IP
hops w/o encapsulation? Or with encapsulation?

Is "path length" weighted by intermediary link bandwidth or not?

What is an "optimal path" anyways. Is it the "shortest" of all the
possible "path lengths" between two mobiles? Or maybe there's a degree
of tolerance?

How much need is there for how much optimality and how much gain is
expected. Is there a quantifying experiment proving an overwhelming need
for shorter-than-through-HA paths?

Alex