Subject: RE: [nemo] RE: splitting moving networks (was: DND test)

From: "Soliman Hesham" <[email-masked]>
Date: Fri, 26 Mar 2004 21:26:58 -0500

> It might be useful for vehicle's moving network. 
 > 
 > Even if we prohibit the single prefix assignment to multiple MRs as
 > you said, we still need to confirm whether each MNP is 
 > surely assigned
 > to single MR or not.  But how?  

=> Not sure what you mean, the current spec does that.

 > Do you think we can just treat this as configuration errors and do
 > nothing for this?

=> I'm not sure what you refer to by "this" above.

 > 
 > I think it is much easier to verify whether a mobile network is not
 > split or not. HA can ask to one of MR whether the other is onlink
 > or not (ex. check ND cache). If not, HA can reject BUs from both MRs.
 > Of course, there isn't such operation in the basic nemo though.

=> On the surface this seems easy but not if you consider
the corner cases, MR reboot, link failures....etc.
I don't think it's that easy actually.

 > 
 > If NEMO can detect the split mobile network and prohibit the
 > split mobile network, there is no problem for the same MNP
 > configuration.

=> I find this logic a bit skewed actually. Of course if 
you start with shared MNPs then it follows that if we can
prevent splitting then everything is ok. There is only 
a small problem: you can't prevent splitting. 

Hesham

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From: Ryuji Wakikawa <[email-masked]>
Date: Sat, 27 Mar 2004 14:16:49 +0900

> => Not sure what you mean, the current spec does that.

Prefix table. Yes, your are right.
I am not sure the use of prefix table guarantee the 1MNP-1MR all the
case. 

When MR has multiple egress interfaces and register each CoA with
respective HoA, HA can not distinguish between the case when one MNP
assigned to two MRs and the case of one MNP to multihomed MR. 
But we can solve the multihomed MR case with draft-wakikawa-mip6-multiplecoa-02:-)

When each MR registers to different HAs, we need to verify whether
prefix table of each HA is consistent or not. Well, we can use HAHA like
protocol for this.

> => I'm not sure what you refer to by "this" above.

the case when HA detects there are multiple MRs for the same MNP.

> I don't think it's that easy actually.

I don't see any problem here.

HA does not have the binding for the MR that reboot or lost connectivity.
Only when HA has multiple bindings for the same MR, it checks the
split network with registered MRs. 

> a small problem: you can't prevent splitting.

How skewed? 

I think there are two options here for the splitting.
The nemo prohibit the split mobile network somehow.
The nemo allow the split mobile network for the same MNP (i.e. HA
somehow know which LFN is located which MR and deliver packets correctly
to target MR, etc)

I do not see  big advantages on the latter case. If we have detection
mechanism of splitting, nemo can support the configuration of the 1MNP
to more than 1 MRs. 

ryuji

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From: Ryuji Wakikawa <[email-masked]>
Date: Sat, 27 Mar 2004 14:16:49 +0900

How skewed? 

ryuji