Subject: [nemo] The question about NEMO basic support

From: "Jongkeun Na" <[email-masked]>
Date: Thu, 3 Jul 2003 00:09:35 +0900

Hello Vijay,

I have a question for prefix table described in the draft.

In case that prefix table is not pre-configured in HA, MR should use
explicit or combined binding mode. Right?

Let's assume that MR and HA can run dynamic routing protocol and prefix
table is not pre-configured.

If MR try to do implicit binding, by the draft, MR cannot set up the
bi-directional tunnel with its HA because HA will send BACK with '143'
status code(Mobile Network Prefix Information information unavailable)
for the requested BU.

I think HA should allow the implicit BU from MR that runs dynamic
routing protocol because the draft says that prefix table is an optional
data structure from the terminology description of section 2. Or, the
draft should say prefix table MUST be maintained by HA.

It looks like unclear to me. Could you explain that for me?

Best Regards,

/Jongkeun

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From: Vijay Devarapalli <[email-masked]>
Date: Wed, 02 Jul 2003 09:58:51 -0700

> In case that prefix table is not pre-configured in HA, MR should use explicit or combined binding mode. Right?

right. 

> 
> Let's assume that MR and HA can run dynamic routing protocol and prefix table is not pre-configured.

when the MR and HA run a dynamic routing protocol there is
no need to include an prefix information in the Binding
Update. infact the HA should not try to determine the 
prefix from the Binding Update. the routing protocol updates
will carry the prefix information. do you think we need an
explicit flag in the Binding Update for this? 

Vijay

> 
> If MR try to do implicit binding, by the draft, MR cannot set up the bi-directional tunnel with its HA because HA will send BACK with `143' status
> code(Mobile Network Prefix Information information unavailable) for the requested BU.
> 
> I think HA should allow the implicit BU from MR that runs dynamic routing protocol because the draft says that prefix table is an optional data structure
> from the terminology description of section 2. Or, the draft should say prefix table MUST be maintained by HA.
> 
>  
>

---

From: Vijay Devarapalli <[email-masked]>
Date: Wed, 02 Jul 2003 09:58:51 -0700

right. 

Vijay

---

From: "Jongkeun Na" <[email-masked]>
Date: Thu, 3 Jul 2003 10:33:28 +0900

> explicit flag in the Binding Update for this?

Yes, I thought an explicit flag is required for HA to properly handle
this situation.

/Jongkeun
> > If MR try to do implicit binding, by the draft, MR cannot set up the
bi-
> directional tunnel with its HA because HA will send BACK with `143'
status
> > code(Mobile Network Prefix Information information unavailable) for
the
> requested BU.
> data structure
> > from the terminology description of section 2. Or, the draft should
say
> prefix table MUST be maintained by HA.
> >
> >
> >

---

From: "Jongkeun Na" <[email-masked]>
Date: Thu, 3 Jul 2003 10:33:28 +0900

/Jongkeun
bi-
status
the
say

---

From: Vijay Devarapalli <[email-masked]>
Date: Thu, 10 Jul 2003 23:13:51 -0700

hi Jongkeun,

please take a look at further discussion on this thread
at http://people.nokia.net/vijayd/nemo/issue6.txt.

the DT members feel that this a matter of config at the
Home Agent, and there is no need for explicit indication
in the Binding Update. I also would like to avoid
introducing additional bits in the Binding Update.

and I can add the following to Section 8.

     When the Mobile Router and the Home Agent exchange routes
     through routing protocol updates, it is necessary that the
     Home Agent does not create routes to the Mobile network
     when the Binding Update from the Mobile Router is received.
     Any routes to the Mobile Network are created through routing
     protocol updates.

let me know what you think about this.

Vijay

Jongkeun Na wrote:
>>>Let's assume that MR and HA can run dynamic routing protocol and
> 
> prefix
> 
>>routing protocol because the draft says that prefix table is an
> 
> optional
> 
>>data structure
>>

---

From: Vijay Devarapalli <[email-masked]>
Date: Thu, 10 Jul 2003 23:13:51 -0700

hi Jongkeun,

Vijay

---

From: "Jongkeun Na" <[email-masked]>
Date: Sat, 12 Jul 2003 00:20:54 +0900

Hi Vijay,

> at http://people.nokia.net/vijayd/nemo/issue6.txt.

In case of using implicit mode BU, HA checks its prefix table whether
there is any entry having MNP mapped from MR's HoA. The last paragraph
of section 6.6 says as follows:
  "The Home Agent sets the status code in the Binding Acknowledgement
   to '143' (Mobile Network Prefix information unavailable) in order
   to indicate the Mobile Router that the received Home Address in the
   Binding Update does not match any prefix entry in the pre-configured
   prefix table.  This is used in the Implicit case where the Mobile
   Router does not include any prefix information in the Binding
Update."
The above statement is not perfect in describing the case of running
dynamic routing protocol. My point is that there is no need to refer the
prefix table by HA when HA know that HA and MR use the dynamic routing
protocol because the prefix information will be set in HA's routing
table via dynamic routing update. So, there is need to distinguish
between one implicit mode BU depending on the prefix table configuration
and the other implicit mode BU depending on routing table for the check
of MNP availability by HA.

>      Any routes to the Mobile Network are created through routing

Good, better than no there.

> let me know what you think about this.

Yes, HA can distinguish both implicit modes if it can know automatically
through IGP routing interaction/configuration at home that MR run
routing protocol and still will run routing daemon while away, or if the
administrator configures one entry of the prefix table with new
field(Ryuji's comment) that indicates MNP will be set by routing update.
First is not clear but second is properly good. 

I totally agree with the use of new field in prefix table in just this
case. But, IMHO, I think that HA needs to know MR is running dynamic
routing protocol at the moment of each BU if NEMO basic protocol
actively supports  dynamic routing between MR and HA so that HA can
properly or easily handle the prefix management. Anyway, at this time,
it looks like insignificant in NEMO basic support. Thanks.

/Jongkeun

---

From: "Jongkeun Na" <[email-masked]>
Date: Sat, 12 Jul 2003 00:20:54 +0900

Hi Vijay,

/Jongkeun

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From: Vijay Devarapalli <[email-masked]>
Date: Fri, 11 Jul 2003 10:42:26 -0700

> it looks like insignificant in NEMO basic support. Thanks.

okay. I will make it more explicit.

    When the Mobile Router and the Home Agent exchange routes
    through routing protocol updates, the Home Agent MUST NOT 
    create routes to the Mobile network when the Binding Update 
    from the Mobile Router is received. The Mobile Router also 
    MUST NOT include any prefix information in the Binding Update. 
    Any routes to the Mobile Network are created at the Home
    Agent through routing protocol updates.

this goes into section 8.

Vijay

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From: Vijay Devarapalli <[email-masked]>
Date: Fri, 11 Jul 2003 10:42:26 -0700

Vijay