Subject: RE: [mobile-ip] re:draft-ohnishi-mobileip-mbg-00.txt

From: [email-masked]
Date: Thu, 19 Jul 2001 15:03:49 -0500

Hello,
 
With MBG you are introducing another new mobility agent to achieve IP
mobility and I am not sure if the benefit outweighs the simplicity of
just having H/FAs and triangle routing.
The ideal solution would be to achieve route optimization using only
the end-points of the communication (MN-CN). But in view of such a
solution being difficult to deploy for IPv4, other approaches may need
to be considered, but I would like to get a sense of greater consensus
in the WG on this. 
 
>Glenn Morrow wrote:
>
>Hiroyuki and Yasushi, 
>
>In reference to your draft: 
>
>http://www.ietf.org/internet-drafts/draft-ohnishi-mobileip-mbg-00.txt 
>
>I have a few questions and comments: 
>
>Would the MGBs be similar or perhaps even the same border routers
>between autonomous systems of 2 ISPs such as two cellular ISPs? 
>
>What signaling protocol are you looking at to distribute the fact that
>the address ranges are mobile address from the HA to the MGBs: BGP,
>OSPF, IS-IS or do you feel that this can be done with simple
>configuration?  
>
>It seems to me that the conveyance of this information would also
>constitute an IP roaming agreement. An automatic, routing
>protocol-based way of setting these up would be of benefit
>IMO. Furthurmore, I believe some similar work should be done to
>identify geographical adjacency for handoff purposes. 
>
>Question to the chairs and/or ADs: 
>
>Would this work fall under MIP WG or routing WGs? 
>
 
Route optimization is within the scope of the MIP WG. However the
aspect of updating MBGs with addresses of MNs is probably outside the
scope of MIP. Especially if you are planning on using some form of
signaling or using routing protocols (as you suggest).
 
>Are you planning any follow-up work on this? 
>
>The expect that the antagonists to this draft may complain about the
>number of per-node routes and what this will do to the routing table
>size. Last time I checked route lookups were pretty fast in most of
>the newer products - even with fairly large routing tables;
>nevertheless, I expect there to be some contention on this. Has there
>been any analysis on this? 
>
 
It would be good to see some results of analysis/simulations of this
proposal. 
 
>Some positive comments I have on this is that it does indeed seem to
>be a very realistic deployment method for route optimization. I have
>not heard of any plans to support route optimization on IPv4 hosts by
>any of the major OS vendors. It makes sense to me to distribute the
>fact that certain addresses are mobile to portions of the network. I
>honestly believe that there are other reasons such as location privacy
>to maintain the mobile bindings in routers as well. I believe that
>such functions are better left in purpose built machines that handle
>handle fast lookups on relatively large route tables. Some analysis on
>this aspect would also be useful?  
>
>Another thing I would like to bring up to folks on the list is that
>even in IPv6, there is no MUST that CN hosts support the binding
>functions of MIPv6. With this in mind, I expect there will be nodes
>out there that don't do it. So even in IPv6, the ubiquity of route
>optimization is still in question. This gives credence to the
>reasoning for the solution in IPv6 as well.  
>
 
But that's not the point. IPv6 nodes are capable of supporting route
optimization and if they choose not to, then I guess you just live
with triangle routing. But I do not see this as a reason to apply MBG
to IPv6. Also note that it is quite possible that a CN which supports
route optimization is still very much capable of rejecting a binding
update from the MN (for any number of reasons).

>Another thing I would like to point out that the signaling methodology
>seems quite similar, as far as the MGP querying the HA for the
>binding, to some the initial work on the GES, 8+8 concepts. You seem
>to be doing the query without having to changing the IP header or mess
>with the addressing schemas - a bonus IMHO. The fact that you are
>using the mobile IP HA instead of something like DNS is also a good
>idea IMO due to speed and an already overloaded DNS. 
>
>It also seems to me that this would allow IPv4 ISPs to offer the
>service without having to fork-lift all of their clients' host
>operating systems. A money saving and realistic idea. 
>
>On the analysis questions - are there any papers available which
>explore these topics you could point us to?  
>
>Thanks, 
>
>Glenn 
 
Cheers,
-Basavaraj

---

From: Hiroyuki OHNISHI <[email-masked]>
Date: Sat, 21 Jul 2001 01:37:31 +0900

Hello,

> to be considered, but I would like to get a sense of greater consensus

I agree with you.

I think it is better to prepare another method which can coexist with
the original route optimization.

> It would be good to see some results of analysis/simulations of this

The paper can be found at the following URL as "Mobile IP route
optimization method for a carrier-scale IP network".
http://www.geocities.co.jp/SiliconValley-Cupertino/8477/

In our laboratories, we made a prototype using this method to confirm
the behaviors. 

Thanks,

Hiroyuki