On Fri, Dec 2, 2011 at 09:18, Tao Sun <hisun...@gmail.com> wrote:
> What I meant is that a protocol and IETF perspective, you can do this
>> today using RIOs. So the protocol is there if 3GPP wants to use it. The
>> 3GPP specs need to be updated regardless of whether we decide to
>> standardize the proposed DHCPv6 route option or not.
>>
> We cannot only discuss the aplicability in IETF perspective. It is indeed
> significant change. The operator always needs to consider the huge number
> of legacy device and network elements. Change user's device and update
> network elements are really non-trival things.
>
Of course. But since the specs need to be updated anyway, and
implementations have to be updated anyway, the fact that changing existing
implementations is a lot of work is not an argument in support of either
RIO or DHCPv6 route: both require work to be done. RIO has the advantage
that less work needs to be done, because the protocol and some
implementations exist already. I know that on Android it would be much
easier to implement RIO than a DHCPv6 route option.
> Again, I still think regardless which mechanism is used. MIF shall
>>> address the issue of multiple sources of informaiton.
>>>
>>
I think MIF should deal with the issue of how to make things work using
multiple interfaces. Making things work in two different ways on one
interface is orthogonal.
> There are two types of scenarios. 1) A host is connected to the mobile
>>> network and WiFi at the same time, a typical scenario of MIF. 2) A mobile
>>> host connects to multiple APNs simultaneously, i.e., multiple PDN
>>> connection is established. The type 2) scenrio is also considered to be
>>> addressed in the OPIIS (Operator Policies for IP Interface Selection)
>>> work item in 3GPP.
>>>
>>
>> #1 can't be solved using either the DHCPv6 route option or RIOs because
>> in general the carrier network doesn't know the IPv6 address of the default
>> gateway on the wifi network.
>>
> I don't understand why one interface need to know the address of the
> default gateway on the other network. If neither DHCPv6 and RIO cannot
> solve this MIF scenario, what solution can solve it?
>
The default gateway address on the other interface is needed if you want
offload traffic to the other interface. That's what I thought you meant.
If all you want to do is say "this carrier walled garden is reachable
through the carrier interface, and the rest of the interface is over wifi",
then you can do that using either RIOs or DHCPv6 route option.
> I don't see how Section 3.4 of this draft ("applicability to routers")
>>>> is relevant to this discussion. Section 5.2 of RFC 5191 describes a
>>>> different scenario (two routers on the same link) than the one you
>>>> suggested here (one router on a given link).
>>>>
>>> Section 3.4 related with your previous question, the hotspot router is
> a multi-homing router which may need some specific route.
>
Sure, but that specific route can be given to that router in many ways
(static configuration, RIO, routing protocol). We don't have to define a
new DHCPv6 route option to do that.
> To us, its a compelling reason due to the network managment/operation,
>>>> per-subscriber service, foresee burden of modification to existing gateway
>>>> and specifications.
>>>>
>>>
>> Who is "us", and what is the use case? I don't see why the ones discussed
>> so far can't use RIOs.
>>
> Us means operators owns and manage both cellular network and WiFi netowrk.
> WiFi plays more and more important roles in mobile operator's network.
>
Then please explain the use case in more detail, and how you would use the
proposed DHCPv6 route option to solve the use case. I think you'll find
that what you're trying to do can be done today (from a protocol
perspective) using RIOs.
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