Re: [Mobopts] MPA review

Ashutosh Dutta <> Fri, 06 June 2008 02:56 UTC

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Date: Thu, 05 Jun 2008 22:56:35 -0400
From: Ashutosh Dutta <>
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To: "Koodli, Rajeev" <>, Nakhjiri Madjid-MNAKHJI1 <>
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Subject: Re: [Mobopts] MPA review
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Rajeev, Madjid,
                 Thanks for your review and comments on the MPA draft. 
We will submit a revised version addressing your comments and suggestions.


Koodli, Rajeev wrote:
> Hi,
> my high-level comment is that the document captures many things. While
> this is a good thing in one way, it diminishes the focus as a bye
> product, unfortunately. So, I am suggesting that it should be
> streamlined to make it crisp to better retain its focus on pre-auth
> related issues, framework and procedures for inter-domain handovers.
> More comments below:
> Regards,
> -Rajeev
> The paragraph starting with "An end-to-end delay consists of several.."
> is too dense and long. I am not sure if all of the text is needed.
> Please consider making this brief, and keep only the parts which are
> essential. In general, detailed descriptions of the previous work should
> be referenced out, and not be repeated here.
> "This type of Inter-technology handover is often
>    called as Vertical Handover since the mobile makes movement between
>    two different cell sizes."
>                       ^^^^^^^^^^ ??
> Section 2 is titled "Inter-domain handover", but it includes the
> definitions for different types of handovers. Perhaps revise the section
> heading to something like "Handover Types". Also, please provide more
> succinct definitions. You may move details which may be useful (but not
> crucial) to an Appendix.
> (I am trying to see if we can make the presentation little more
> crisper).
> Section 3 provides a good survey. You may want to revise the title to
> "Related Work"
> Section 4 - Applicability should be no more than two paragraphs I think
> Shouldn't the Terminology Section be earlier, say right after
> Introduction?
>  Section 6.1:
> "MPA provides four basic procedures to provide this functionality.
>    The first procedure is referred to as "pre-authentication", the
>    second procedure is referred to as "pre-configuration", the
>    combination of the third and fourth procedures are referred to as
>    "secure proactive handover"."
> Either state 4 procedures or 3 procedures.
> Section 6.1, paragraph 3 is important for people to get a high-level
> overview. It is too condensed. Please try to make the steps clear. And,
> do no use acronyms (such as MMP) that are not defined earlier.
> PHT (Proactive Handover Tunnel) -> Proactive Handover Tunnel (PHT)
> Section 6.2:
> "..securely executing a configuration protocol to
>    securely deliver an IP address .."
> too many 'securely'
> "An access router is a router that is responsible for the other part
>    of pre-configuration, i.e., securely executing a tunnel management
>    protocol to establish a proactive handover tunnel to the mobile node.
>    The signaling messages of the configuration protocol MUST be
>    protected using a key derived from the key corresponding to the
>    MPA-SA."
> May be I missed it.. How does the AR get the corresponding keys? You
> describe it later, but please make a reference
> Section 6.3:
> Step 2: "It then performs pre-configuration,
>    with the configuration agent using the configuration protocol to
>    obtain an IP address, say nCoA (new care-of address), and other
>    configuration parameters from the CTN, and with the access router
>    using the tunnel management protocol to establish a proactive
>    handover tunnel.  "
> There are two distinct steps here: pre-configuration, tunnel set up.
> You should not combine them into a single sentence (this applies as a
> general rule). Also, specify what "other configuration parameters"
> mean; it should be clear.
> Step 4:
> "The mobile may execute the tunnel
>    management protocol to delete or disable the proactive handover
>    tunnel and cache nCoA after deletion or disabling of the tunnel. "
>  Do you allow tunnel deletion prior to link switching? If so, what does
> the AR do for packets arriving for nCoA, once tunnel interface is
> deleted? "Caching" an address does not sound right.
>  "An example call flow for MPA is shown in Figure 3 and Figure 4."
> Why is this an example call flow? This is _the_ call flow right?
> Section 7:
> Please focus on the parts essential to the MPA, and move rest of the
> description to the Appendix.
> Section 7.3.5. is perhaps not crucial, and can be moved to the appendix
> Section 7.4 is not necessary I think. You have created a tunnel
> interface between the MN and AR. There are references on how to ue ND
> over tunnel interfaces. You can also disable it.
> Sections 7.6 and 7.9 are related, and should be condensed into one
> section I think.
> Section 7.8 does not belong to the main body of the document
> Section 8 on Deployment Issues: IMHO, this may be a little early for the
> framework. I would consider a separate document once enough experience
> is obtained. If there are parts you consider worth documenting now,
> please move them to the Appendix.
> Section 9 is important since it is supposed to capture the Inter-domain
> Handover, which is the primary focus of this ID.
> I would consider the key issues that come up, and move multicast
> mobility out, or considerably condense it.
> In sum, please revise the ID keeping the essential parts in the main
> body, referencing known work (without too much description) and moving
> the adjoining and descriptive material you consider necessary to
> appendix.
> General presentation:
> please revise phrases such as "A mobile may like to.." to "A mobile may
> wish to.." And, please avoid sentences such as "..should not be a big
> problem".
> "Third, a mobility optimization mechanism needs to support not only
> multi-interface terminals where multiple simultaneous connectivity
> through multiple interfaces can be expected, but also single-interface
> terminals."
> RKo> I assume you mean single interface connectivity right? Even with
> multiple interfaces, you could still have a single interface
> connectivity.
> "References [RFC2679], [RFC2680] and 2681 [RFC2681] describe some of the
> measurement techniques for delay and
>    jitter."
> RKo> "Measurement techniques for delay and jitter are described in [],
> [].."
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