Subject: [mobile-ip] Mobile IPv4 Dynamic Home Agent Assignment Framework

From: Milind Kulkarni <[email-masked]>
Date: Fri, 24 Jan 2003 11:35:50 -0800

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-kulkarni-mobileip-dynamic-assignment-00.txt

Your comments are appreciated.

Abstract:

Mobile IP (RFC 3344) uses the Home Agent (HA) to anchor 
sessions of a roaming Mobile Node (MN).  The distance between 
a MN and HA affects the latency for control and data traffic. 
When the distance between the MN and HA is large, the resulting 
latency may be unacceptable. Therefore, it is advantageous to 
select a nearest HA to the MN during initial registration.  
There are other reasons for assigning an optimal HA beyond just 
locality, such as administrative policies, load balancing etc. 
         
This draft proposes a generic lightweight dynamic home agent 
assignment framework. The goal of the framework is to provide a 
mechanism to assign an optimal HA for a Mobile IP session while 
allowing any suitable method for HA assignment. The mobile node 
uses NAI extension for home address assignment.

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From: Behcet Sarikaya <[email-masked]>
Date: Fri, 24 Jan 2003 14:11:05 -0600

Hello Milind,
  Have you looked at:

> http://www.ietf.org/internet-drafts/draft-ietf-aaa-diameter-mobileip-13.txt

I think it also does dynamic HA assignment and is about to become an RFC.

Regards,

-- 
Behcet

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From: Milind Kulkarni <[email-masked]>
Date: Fri, 24 Jan 2003 15:52:45 -0800

Behcet,

Thanks for your comment. Yes, we have looked at the Diameter draft 
you specified. As you may know, it is a diameter specific scheme. 

In our draft we are proposing a framework only. The framework allows 
dynamic HA assignment using any suitable method, such as DNS, AAA, 
DHCP and not just Diameter. So the framework doesn't mandate use of a 
specific method, at the same time it doesn't preclude Diameter
application either. We have been hearing that our customers prefer
a solution that accommodates their existing infrastructure. Not 
all of them have same infrastructure, hence the framework is
open for accommodating any implementation. In essence the framework 
allows the RRQ to be responded to with another home agent address.
How one manages that is independent of infrastructure.

Thanks again,
Milind

-- 
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  Milind Kulkarni               Tel  : 408.527.8382 
  Cisco Systems, San Jose.      Pager: 408.397.2345 or send mail 
                                       to [email-masked]
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From: Yoshiyuki Tsuda <[email-masked]>
Date: Mon, 27 Jan 2003 18:35:46 +0900

Hi forks,

 It's true that during key distribution an HA will be assigned
 dynamically, in case a mobile node doesn't have a security
 association with that assigned HA.
 But, draft-kulkarni-mobileip-dynamic-assignment-00.txt covers
 cases where a mobile node already has a security association
 with assigned HAs, too. Thus, key distribution mechanisms aren't
 required in such a case.  At this point, I have checked the key
 distribution I-D once again, but it never mentioned such cases.

 Also, recently, for security reasons, the dynamic HA resolution
 method, described in rfc3344, doesn't work well, because most
 last-hop routers won't translate the subnet-directed broadcast
 address into the link-layer broadcast address.

 For these reasons and so on, draft-kulkarni-mobileip-dynamic-
 assignment-00.txt is worth consideration, I believe.

 Anyway, if Cisco's HA/FA will support the dynamic HA assignment
 based upon that I-D, I'll implement it in our mobile nodes, too. :)

Thanks.
-Yoshi