Re: [Seamoby] Proposal on Sync/NoSync Requirement

Madjid,

> Don't know if we can use NEED Not (certainly fits for the first SHOULD NOT,
since
> that one sounds like we are advising against it).

We should (SHOULD? :-) use RFC language.

> How would you allow particular features get synch service, if there is no
inbuild
> mechanisms in CT?

Because the CT protocol would be just a container format that could be reused by
many different feature specific protocols. For example, one could use the CT
container to define an option for use along with handover signaling to transfer
header compression context. Or, one could use SCTP to transfer security, QoS,
and AAA context not requiring any synchronization with the handover signaling.
The latter would require a separate protocol description for how the container
format is used with the particular transport. For most protocols, the two are
bundled, but they are conceptually separate and here I can see reasons for
separating them.

>
> I think we can talk about synchronization when there are two copies at
> two different places. I think the solutions should seriously avoid this,
> as we did in our proposal. Care should be taken so that you don't have to
> update a context at both oldAR and newAR. I think as you said for header
compression
> context, you should have the context updated only at one location and when
> it is only at one location, how can we call it synchronization?
>

Because it is synchronized with an external event, namely handover. With context
that is not sync sensitive  there is no requirement for synchronization with
handover because the change in routing doesn't invalidate the context on the old
router. Conversely, if the non-sync sensitive context is sent a bit early, there
will similarly not be a problem.

This is not to state that the non-sync sensitive context isn't dynamic, just
that the event of handover doesn't invalidate it per se.

>
> You would on the other hand get problem with dynamic context, if
> some context that you sent over, gets lost or corrupted. Once this happen
> then, you can see whether the context has changed (in which case you need a
refresh)
> or not (you only need a retx).
>

Dynamic context means that it is changing as the mobile's traffic goes through
the router, right? So I view that as requiring synchronization with an external
event, namely handover. Something like accounting information would qualify, as
well as header compression state. On the other hand, a user's SLA would not,
because handover wouldn't invalidate it.

                jak

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