Subject: Re: [nemo] Issue 10

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 04 Aug 2003 15:23:45 +0200

Vijay Devarapalli wrote:
> hi Pascal and all,
> 
> I want to see if we can close issue 10.

I was not heavily involved in the discussions around this issue.  I find
the below text about issue 10 reasonable, good to keep igp separated
from implicit mode.

But I have another related question.  I was wondering whether there
might be a necessity to clearly state in the draft which modes must be
implemented by whom for this to be a relevant spec.  An example would
be: all MR's MUST implement at least "explicit prefixlen" and all HA's
must implement all three modes.  This is just an example, I'm looking to
know whether it is good or not to be specific about what's mandatory to
be implemented.

Alex
GBU

> 
> Binding Ack status 143 is supposed to be used when the HA cant figure
>  out which MNP belongs to the MR in the implicit mode. it is every 
> essential to have this error status because we dont want the MR 
> assuming that the HA has set up forwarding for the MNP when it 
> actually didnt. it doesnt matter which mechanism (Prefix Table being 
> one) is used by the HA in the implicit mode.
> 
> status code 143 is not supposed to be used when an IGP is being run 
> over the MR-HA tunnel. when an IGP is being used, the HA just waits 
> for the routing protocol updates from the MR and does not attempt to 
> create any routes if the BU did not contain any prefix information.
> 
> there are basically three different mechanisms by which the MR 
> propagates routes to the HA.
> 
> 1. explicit mode. the Binding Update contains the prefix information 
> in the mobility options (Mobile Network Prefix option or Mobile 
> Network Prefix Length option)
> 
> 2. implicit mode. the HA figures out the MNP through mechanisms not 
> defined in the draft. a pre-configured Prefix Table is one such 
> mechanism that you can use. a static route configuration (manually 
> added) is another one.
> 
> 3. IGP over the MR-HA tunnel.
> 
> I dont want to mix up (3) with (2). I would like to keep the IGP part
>  separate from the rest of the specification. I am not too sure we 
> have taken care of all the issues related to running an IGP over the 
> tunnel.
> 
> does this make sense?
> 
> Vijay
>

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From: Alexandru Petrescu <[email-masked]>
Date: Mon, 04 Aug 2003 15:23:45 +0200

Alex
GBU

---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 04 Aug 2003 15:26:55 +0200

Alexandru Petrescu wrote:
> might be a necessity to clearly state in the draft which modes must
> be implemented by whom for this to be a relevant spec.  An example
> would be: all MR's MUST implement at least "explicit prefixlen" and
> all HA's must implement all three modes.  This is just an example,
> I'm looking to know whether it is good or not to be specific about
> what's mandatory to be implemented.

...the reason being that one might not want to have a situation where MR
only implements say explicit prefixlen mode and HA only implements say
explicit network mode.

Alex
GBU

---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 04 Aug 2003 15:26:55 +0200

Alex
GBU

---

From: Vijay Devarapalli <[email-masked]>
Date: Mon, 04 Aug 2003 10:36:02 -0700

> know whether it is good or not to be specific about what's mandatory to

good point. IMO, the Home Agent MUST implement all 
modes in section 5.2. support for running an IGP over 
the MR-HA tunnel is still optional. the MR may 
implement any method it wants.

I made this issue 11.

proposed text

6. Home Agent Operation

   In order for a Mobile Router to operate correctly, the Home Agent
   MUST satisfy all the requirements listed in section 8.4 of [1].  The
   Home Agent MUST implement all the modes described in Section 5.2.

as for the MR we already have some text in section 5.2
   
   The Mobile Router uses
   one of the following modes to instruct the Home Agent to determine
   the prefixes owned by the Mobile Router.

Vijay

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From: Vijay Devarapalli <[email-masked]>
Date: Mon, 04 Aug 2003 10:36:02 -0700

I made this issue 11.

proposed text

6. Home Agent Operation

   
   The Mobile Router uses

Vijay

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From: Thierry Ernst <[email-masked]>
Date: Tue, 5 Aug 2003 09:24:15 +0900

Hi,

This sounds reasonable to me to have only HA implementing all modes. As
for the HA, isn't it one of the modes that MUST at least be supported ?
What happens if 2 MRs in the same mobile network don't implement the
same mode ?

Thierry.

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From: Thierry Ernst <[email-masked]>
Date: Tue, 5 Aug 2003 09:24:15 +0900

Hi,

Thierry.

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From: Vijay Devarapalli <[email-masked]>
Date: Mon, 04 Aug 2003 17:43:57 -0700

Thierry Ernst wrote:
> for the HA, 

you mean the MR?

> isn't it one of the modes that MUST at least be supported ?

I thought thats obvious from the current text

>    the prefixes owned by the Mobile Router. 

this means that the Mobile Router MUST implement one of the
modes.

> What happens if 2 MRs in the same mobile network don't implement the

shouldnt be a problem as long as the HA implements both. do
you see a problem?

Vijay

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From: Vijay Devarapalli <[email-masked]>
Date: Mon, 04 Aug 2003 17:43:57 -0700

you mean the MR?

Vijay

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From: Thierry Ernst <[email-masked]>
Date: Tue, 5 Aug 2003 09:52:32 +0900

Hi,

> > This sounds reasonable to me to have only HA implementing all modes. As

Sorry, misstyping. Yes, MR.
 
> shouldnt be a problem as long as the HA implements both. do

I don't see any specific problem but it may be one once we do some
testing (?): what happens if a multihomed mobile network has 2 MRs, and
1 MR uses implicit, the other uses explicit ? Will it work ? It this
reasonable to allow this ? 

Thierry

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From: Thierry Ernst <[email-masked]>
Date: Tue, 5 Aug 2003 09:52:32 +0900

Hi,

 

Thierry

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From: Ryuji Wakikawa<[email-masked]>
Date: Mon, 04 Aug 2003 20:49:48 +0900

Hi,

At Tue, 5 Aug 2003 09:52:32 +0900,
> reasonable to allow this ? 

I don't see any problem, neither:-)

I personally think this evaluation should be done in the multihoming
draft, but not in the basic.

regards,
ryuji

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From: Ryuji Wakikawa<[email-masked]>
Date: Mon, 04 Aug 2003 20:49:48 +0900

Hi,

regards,
ryuji