Re: [netlmm] Timestamp Option for Message Ordering

[Sandesh <[e-mail]>]

Hi Vijay,

I am proposing an alternate solution to the issue which timestamp or
sequence number (sent in PBU after sequence number sync between MAGs )
are trying to solve.
In other words this solution intends to remove the need of timestamp
and sequence number sync between MAGs.

Thanks and Regards,
Sandesh

On Tue, Jul 29, 2008 at 6:36 PM, Vijay Devarapalli <[e-mail]> wrote:
> Sandesh,
>
>> I am proposing a solution for the problem which
>> section '5.5 Timestamp Option for Message Ordering'
>> of draft-ietf-netlmm-proxymip6-18.txt intends to solve.
>> Please ignore this mail if this approach has been discussed earlier.
>>
>> IMO problem can be defined as following -
>> ------------------------------------------
>> When LMA has received two or more PBU message for binding
>> lifetime extension
>> from two or more MAGs (and has not received PBUs from with
>> lifetime = 0
>> indicating MN detachment from all except one) then (in the
>> absence of sequence
>> number and timestamp) how can it be find out which MAG the MN is
>> actually connected to.
>
> One of the approaches, the timestamp or the sequence number is always
> used. So we don't have a scenario where neither are present.
>
> Vijay
>
>>
>> SOLUTION
>> ------------------------------------------
>> In this solution a new trigger type in BRI (from LMA to MAG)
>> is added which
>> indicate 'PBU Registration Confusion'.
>>
>> MAG Procedures -
>> MAG PROCEDURE 1. MAG retransmits PBU if matching PBA is not
>> received before
>>   retransmission timeout. If MN is attached to MAG it keeps on
>>   retransmitting PBU until it receives matching PBA. If MN detaches
>>   from MAG it retransmits PBU with lifetime = 0 a number of times (N).
>> MAG PROCEDURE 2. MAG sends PBU again if it receives BRI (Trigger =
>>   PBU Registration Confusion). And after that it does PBU
>> retransmissions as per MAG PROCEDURE 1.
>>
>> LMA procedures -
>> LMA CASE 1: LMA received two or more PBUs (with lifetime !=0)
>> and it has not
>> sent PBA to any of the MAGs.
>> It does not send PBA to any MAG. Soon it will receive the PBUs
>> with lifetime = 0 from MAGs from which MN has detached and
>> PBU(lifetime !=0) retransmission from MAG to which MN is actually
>> attached.
>> MN is considered to be attached to a MAG if and only all MAGs
>> except one sends
>> PBUs(lifetime = 0) and that one MAG sends PBU (lifetime !=0).
>> A max timer can be defined to declare that MN is not attached
>> to the MAG if no
>> PBUs are received from a MAG (which first sent PBU with
>> lifetime !=0) for
>> that max timer duration.
>> After the decision has been taken about which MAG an MN is
>> attached to PBAs
>> (status =0) are sent to all the MAGs.
>>
>>
>> LMA CASE 2: LMA received two or more PBUs (with lifetime !=0)
>> and it has
>> sent PBA (Status = 0) to one of the MAGs.
>> LMA send BRI(Trigger = PBU Registration Confusion) to the MAG to
>> which it has sent PBA (Status = 0). After that LMA follows the
>> procedure defined in Case
>>
>> Sequence number in PBU can be considered per MAG and can be
>> used to drop
>> old/duplicate PBUs from the same MAG.
>>
>> Disadvantage of this approach is that it will take little
>> longer to declare
>> which MAG a MN is attached to.
>>
>> Advantages of this solution are -
>> - MAG need not send timestamp to LMA in PBUs
>> - MAG need not sync sequence number with other MAGs.
>>
>> Thanks and Regards,
>> Sandesh
>> _______________________________________________
>> netlmm mailing list
>> [e-mail]
>> https://www.ietf.org/mailman/listinfo/netlmm
>
>



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