Re: [16NG] DAD in IEEE802.16

[Behcet Sarikaya <[e-mail]>]

This is covered in Sec. 9.2 of <draft-ietf-16ng-ipv6-over-ipv6cs>.
If the two conditions given there are satisfied then no DAD is needed.

--behcet

----- Original Message ----
From: Tjandra Paula-CPT015 <[e-mail]>
To: Behcet Sarikaya <[e-mail]>; gabriel montenegro <[e-mail]>
Cc: [e-mail]
Sent: Thursday, May 3, 2007 5:18:38 PM
Subject: RE: [16NG] DAD in IEEE802.16


Is it a requirement to assign unique prefix per MS in WiMAX?
<draft-ietf-16ng-ipv6-over-ipv6cs> seems to imply that it is.
Assuming that the MS/host has a unique prefix, why would the MS/host need to perform DAD?
 
Regards, Paula.



From: Behcet Sarikaya [mailto:[e-mail]] 
Sent: Thursday, May 03, 2007 4:48 PM
To: gabriel montenegro
Cc: [e-mail]
Subject: Re: [16NG] DAD in IEEE802.16


Gabriel,
  Let's take RFC3314. It says:
DAD is not performed, as the GGSN
   will not assign the same address to multiple nodes.

So the context is important. Of course I agree with the above sentence, but in other contexts, DAD is needed.
 
Regards,
 
Behcet

----- Original Message ----
From: gabriel montenegro <[e-mail]>
To: Behcet Sarikaya <[e-mail]>
Cc: [e-mail]
Sent: Thursday, May 3, 2007 4:17:37 PM
Subject: Re: [16NG] DAD in IEEE802.16


Behcet said: "I don't think we can say that DAD is not needed."

This is what the documents I refer to below *already* say is fine under certain conditions. I believe those same conditions are likely to be generally satisfied in 
networks beyond those being explicitly mentioned in those documents (e.g., wimax).

If you want those documents to not say it may be ok to forgo DAD, then it's too late for the RFCs, but perhaps you can still argue it for
the "IP Version 6 over PPP", but better hurry as it is in IESG right now. I happen to think that what it says is correct.

-gabriel


----- Original Message ----
From: Behcet Sarikaya <[e-mail]>
To: gabriel montenegro <[e-mail]>
Cc: [e-mail]
Sent: Thursday, May 3, 2007 11:45:33 AM
Subject: Re: [16NG] DAD in IEEE802.16


Isn't DAD recommended even on p2p links? You are generating an address from either your MAC address or using some random numbers, you can not avoid a collision 100%. I heard that Vista generates a new IPv6 address every hour. I don't think we can say that DAD is not needed.
 
--behcet


----- Original Message ----
From: gabriel montenegro <[e-mail]>
To: Syam Madanapalli <[e-mail]>; Frank Xia <[e-mail]>
Cc: [e-mail]
Sent: Thursday, May 3, 2007 12:00:04 PM
Subject: Re: [16NG] DAD in IEEE802.16


I really don't think it makes sense to consider END, a non-standard, for such a minor issue, which might actually be a non-issue.
DAD itself may not be even needed, as mentioned by Syam already. This point is mentioned informationally in the DAD discussions in:

    Recommendations for IPv6 in Third Generation Partnership Project (3GPP) Standards    
    http://tools.ietf.org/html/rfc3314

    Internet Protocol Version 6 (IPv6) for Some Second and Third Generation Cellular Hosts
    http://tools.ietf.org/html/rfc3316  

and normatively in section 5 of:

  IP Version 6 over PPP
    http://tools.ietf.org/html/draft-ietf-ipv6-over-ppp-v2-02

which is currently in IESG processing. Even though the above docs don't spell out w-i-m-a-x, the link characteristics from the point of addressing are
similar enough that the same considerations can apply.

-gabriel


----- Original Message ----
From: Syam Madanapalli <[e-mail]>
To: Frank Xia <[e-mail]>
Cc: [e-mail]
Sent: Thursday, May 3, 2007 8:38:59 AM
Subject: Re: [16NG] DAD in IEEE802.16


Hi Frank,
 
 
On 5/3/07, Frank Xia <[e-mail]> wrote: 
 
Hi Syam
 
Even in ODAD, there is a normal DAD procedure in parallel.
END is to improve normal DAD, not ODAD.
END can co-work with ODAD well.
 
 
I see no reason to use ODAD along with END.
END might have had better position if it were proposed
before ODAD :-)
 


 
Any way, just as you said, is it useful enough to modify the router?
 
 
Yep, if we can answer this, then we will be in better position to support this proposal.


 
I don't know, but I think that any feasible improvement can be considered.
 
 
I agree.
 
Thanks,
Syam


 
BR
Frank
----- Original Message ----- 
From: Syam Madanapalli 
To: Behcet Sarikaya 
Cc: [e-mail] 
Sent: Thursday, May 03, 2007 2:18 AM
Subject: Re: [16NG] DAD in IEEE802.16

 
Hi Bachet,
 
Doing things deterministically is always good.
But here I am wondering if it is worth the implementation changes on the routers as well as on hosts,
especially on p2p links where the chance of collission is very very remote as the p2p link will be
using just two addresses out of 2 ^64.
 
Assign unique prefix using prefix delegation for each host or  configuring the router not to
construct the IPv6 address using the advertised prefix in case the router advertises the prefix
along with the ODAD may solve the problem completely, I think.
 
 
Thanks,
Syam

 
On 5/3/07, Behcet Sarikaya <[e-mail] > wrote: 
Syam, isn't it better to make it deterministic in p2p links where you have an authoritative address cache?
 
--behcet

 
----- Original Message ----
From: Syam Madanapalli < [e-mail]>
To: Frank Xia <[e-mail]>
Cc: 김상언 < [e-mail]>; [e-mail]
Sent: Wednesday, May 2, 2007 1:02:35 PM
Subject: Re: [16NG] DAD in IEEE802.16


Hi Frank,
 
I understand the proposed END mechanism is more deterministic, however it comes at
a cost: router modification and availability of authoritative address cache.
 
And personally I do not like the RA as a response to DAD NS to tell the host that 
the address is unique, and at NA cannot be used as it will not be interoperable with
unmodified hosts which will treat that the address is duplicate.
 
IEEE 802.16 based hosts would have the unique MAC address, so ODAD would
work well I think.
 
Thanks,
Syam

 
On 5/2/07, Frank Xia <[e-mail] > wrote: 
Hi Syam
 
END can work together with  Optimistic DAD, and some of the description in our draft is
" If END and [OPTDAD] are enabled, the SS will benefit from both the
   reliability and time advantages.
"
 
Any way , there are some constraints for Optimistic DAD, 
please refer to the words form RFC4429:
  * Optimistic DAD SHOULD only be used when the implementation is aware
        that the address is based on a most likely unique interface
        identifier (such as in [RFC2464]), generated randomly [RFC3041], 
        or by a well-distributed hash function [RFC3972] or assigned by
        Dynamic Host Configuration Protocol for IPv6 (DHCPv6) [RFC3315].
        Optimistic DAD SHOULD NOT be used for manually entered
        addresses."
 
BR
Frank
----- Original Message ----- 
From: Syam Madanapalli 
To: Frank Xia 
Cc: Daniel Park ; 김상언 ; [e-mail] 
Sent: Wednesday, May 02, 2007 12:22 PM
Subject: Re: [16NG] DAD in IEEE802.16

 
 
Hi Frank and Sangeon,
 
How about using Optimistic DAD (RFC 4429) to minimize the delay?
 
Thanks,
Syam

 
On 5/2/07, Frank Xia < [e-mail] > wrote: 
Hi Deniel and Sangeon
 
A  solution is proposed in the END draft and it applies to p2p link model as well.
 
http://tools.ietf.org/wg/16ng/draft-xia-16ng-end-01.txt 
 
Comments are welcomed.
 
BR
Frank
 
 
 
 
----- Original Message ----- 
From: Daniel Park 
To: '源�?곸뼵' ; [e-mail] 
Sent: Tuesday, May 01, 2007 6:39 PM
Subject: [16NG] DAD in IEEE802.16

 
[Trimming the list and subject]
 
Sangeon, 
 
IPv6 subnet model document was gone. Its status
is in RFC Queue. If you have any concern regarding
IPv6 DAD, it may take place in IPv6CS or EthernetCS
document in my sense. Can you elaborate on your
concern more specific ?
 
-- Daniel Park
 
 


From: 源�?곸뼵 [mailto:[e-mail]] 

Sent: Monday, April 30, 2007 11:14 PM 
To: [e-mail] 
Cc: [e-mail]; [e-mail]
Subject: Re: 16NG Digest, Vol 5, Issue 22


 
Hi all,
 
The one of the important thing in IEEE802.16 is missed.
RFC 2462 specifies autoconfiguration in wired-based IPv6 Internet. It did not specify configuration time.
To use RFC 2462 specfication in IEEE802.16e network, it is required faster procedure than current DAD procedure.
Has anyone can tell the DAD processing time?
 
If the IEEE 802.16 network will consume more than one seconds to handover at IP layer, Does it practical?
 
So, I would like to propose to add some technical resolution for section 3.1.3 and 3.3.3.
 
regards,

 
2007/4/28, [e-mail] < [e-mail]>: 
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Today's Topics:

  1.  Document Action: 'Analysis of IPv6 Link Models for   802.16
     based Networks' to Informational RFC  (The IESG)


----------------------------------------------------------------------

Message: 1
Date: Fri, 27 Apr 2007 11:30:34 -0400
From: The IESG < [e-mail] >
Subject: [16NG] Document Action: 'Analysis of IPv6 Link Models for 
       802.16 based Networks' to Informational RFC
To: IETF-Announce < [e-mail] >
Cc: Internet Architecture Board <[e-mail]>,  16ng mailing list
       < [e-mail]>, 16ng chair < [e-mail]>,       RFC Editor 
       <[e-mail]>
Message-ID: < [e-mail]>

The IESG has approved the following document: 

- 'Analysis of IPv6 Link Models for 802.16 based Networks '
  <draft-ietf-16ng-ipv6-link-model-analysis-03.txt > as an Informational RFC

This document is the product of the IP over IEEE 802.16 Networks Working
Group.

The IESG contact persons are Jari Arkko and Mark Townsley.

A URL of this Internet-Draft is: 
http://www.ietf.org/internet-drafts/draft-ietf-16ng-ipv6-link-model-analysis-03.txt 

Technical Summary

This document provides different IPv6 link models that are suitable 
for 802.16 based networks and provides analysis of various 
considerations for each link model and the applicability of each link 
model under different deployment scenarios.

Working Group Summary

This document is result of a Design Team that was formed 
to analyze the IPv6 link models for 802.16 based networks.
Based on the recommendations of the design team and this 
document, the working group has chosen the unique-prefix-per-
link/mn model over the previously assumed shared prefix 
model. The new model is in use in the IPv6 over 802.16 IPCS
document (draft-ietf-16ng-ipv6-over-ipv6cs), and has also 
been adopted by the Wimax Forum.

Protocol Quality

Jari Arkko has revied this document for the IESG. 

Note to RFC Editor

Please insert "IEEE" in front of references to 802.16
or other IEEE specification numbers throughout the 
document, including the title.

Please expand "MS" to "MS (Mobile Station)" on first 
occurence in Section 1. Similarly, expand "BS" to
"BS (Base Station)". And later in the document, 
"CS" to "CS (Convergence Sublayer)".

Please expand "MLD" to "MLD (Multicast Listener 
Discovery)" in Section 3.1.3.

Please add the following informative reference: 

  [WiMAXArch]
             "WiMAX End-to-End Network Systems Architecture
             http://www.wimaxforum.org/technology/documents",
             August 2006.

and refer to that from Section 1, 2nd paragraph, 1st sentence.

In Section 3.1, change "on per MS basis" to "on a per MS basis". 

Also in Section 3.1, paragraph 1: change "does not any multicast"
to "does not provide any multicast". And change "illustrates high"
to "illustrate a". Finally, change "one more" to "one or more". 

Change the section titles (3 instances) that say "Reuse of
Existing Standards" to "Reuse of Existing Specifications".

Replace the text in the Security Considerations section
with the following: 

   This document provides the analysis of various IPv6 link models for
   IEEE 802.16 based networks and this document as such does not
   introduce any new security threats. No matter what the link model
   is, the networks employ the same link-layer security mechanisms
   defined in [5]. However, the chosen link model affects the scope
   of link local communication, and this may have security implications
   for protocols that are designed to work within the link scope. This 
   is the concern for shared link model compared other models wherein
   private resources e.g. personal printer cannot be put onto a public
   WiMAX network. This may restrict the usage of shared prefix model
   to enterprise environments.

   The Neighbor Discovery related security issues are document in [RFC

   2461] [RFC 2462] and these are applicable for all the models
   described in this documents. The model specific security 
   considerations are documented in their respective protocol
   specifications.

Place a new top-level section between Sections 5 and 6:

   X. Effect on Routing

   The model used for in a 802.16 network may have a significant
   impact on how routing protocols are run over such a network.
   The deployment model presented in this document discusses the
   least impacting model on routing as connectivity on the provider 
   edge is intentionally limited to point to point connectivity
   from one BS to any one of multiple MSs. Any other deployment
   model may cause a significant impact on routing protocols,
   however, but they are outside the scope of this document. 





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End of 16NG Digest, Vol 5, Issue 22 
***********************************




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------------------------------------------------ 
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Senior Researcher
Infra. Lab., KT
139-791, Woomyeon-dong, Seocho-gu, Seoul, Korea 

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