Re: [802.21] Limit response message length
Hi Qiaobing,
On Fri, Dec 15, 2006 at 03:16:18PM -0600, Qiaobing Xie wrote:
> Yoshi/Michael,
>
> A few thoughts on this:
>
> 1. The network (I guess this means the IS server) may want to impose
> different size limit depending on the mobile is in unauthenticated or
> authenticated state. Should there be a way the IS server can know about
> this?
This is a good point. I believe that the IS server does not have to
know the mobile's authentication state. There are three cases.
Case 1: IS queries originated by State 1 station. Since State 1
station cannot directly communicate with IS server, AP acts as a proxy
MIH IS client on behalf of the station. In this case, the source
address of MIH_Get_Information Request message will be the MAC address
of the AP. The AP should set the per-query MTU needed for State 1
queries.
Case 2: IS queries originated by State 3 station. State 3 station can
directly communicate with IS server. In this case, the source address
of MIH_Get_Information Request message will be the MAC address of the
station. The station may set whatever per-query MTU it wants.
Case 3: IS queries originated by AP. AP may want to generate queries
on behalf of itself for many reasons. In this case, the source
address of MIH_Get_Information Request message will be the MAC address
of the AP. The AP can may whatever per-query MTU it wants.
The IS server cannot distinguish Case 1 and Case 3, but it does not
really have to distinguish the two cases if we expect the AP to set
per-query MTU differently in Case 1 and Case 3.
For all cases, the IS server can impose its own limit less than that
is specified by the IS client.
>
> 2. The actual size limit of a query/response exchange will be the the
> lesser of the mobile's self-imposed limit and network imposed limit.
Yes.
>
> 3. What should be the consequence if the response is over the lesser of
> the mobile limit and network imposed limit? Probably we simply fail the
> query with some error code.
Yes, the IS server should return a response with an error indication
in this case.
Regards,
Yoshihiro Ohba
>
> regards,
> -Qiaobing
>
> Michael.G.Williams@NOKIA.COM wrote:
> >Yoshi,
> >
> >Sounds good. Ideally we want a way for the mobile in one packet to
> >query and the network in one response packet give the response back,
> >esp. in unauth state where fast scanning or high mobility are issues,
> >yes? Is piggybacking the details of limit request or enforcement onto
> >that exchange possible?
> >
> >Michael
> >
> >-----Original Message-----
> >From: ext Yoshihiro Ohba [mailto:yohba@tari.toshiba.com]
> >Sent: Friday, December 15, 2006 10:02 AM
> >To: Williams Michael.G (Nokia-ES/MtView)
> >Cc: STDS-802-21@listserv.ieee.org
> >Subject: Re: [802.21] Limit response message length
> >
> >Yes, the network can always impose its own limit if the maximum size
> >specified by the mobile is still too big.
> >
> >Yoshihiro Ohba
> >
> >On Fri, Dec 15, 2006 at 11:16:10AM -0600, Michael.G.Williams@NOKIA.COM
> >wrote:
> >>HI Yoshi,
> >>
> >>That approach could work, as long as the network would also need to be
> >
> >>able to impose/enforce the limit if the mobile's request is too big,
> >>right? That was Tgu's concern I think.
> >>
> >>Best Regards,
> >>Michael
> >>
> >>-----Original Message-----
> >>From: ext Yoshihiro Ohba [mailto:yohba@tari.toshiba.com]
> >>Sent: Thursday, December 14, 2006 8:50 PM
> >>To: Williams Michael.G (Nokia-ES/MtView)
> >>Cc: yohba@tari.toshiba.com; STDS-802-21@LISTSERV.IEEE.ORG
> >>Subject: Re: Limit response message length
> >>
> >>Hi Michael,
> >>
> >>What I am trying to do is to add a new parameter in
> >>MIH_Get_Information.request/indication primitives, which is used for
> >>specifying the maximum size of InfoQueryParameter to be returned in
> >>the corresponding confirm/response primitives, and a new TLV to carry
> >>the parameter in MIH_Get_Information Request message. This allows the
> >
> >>querier to specify a different MTU for each query so that a smaller
> >>size can be specified for queries performed in State 1 of 802.11.
> >>
> >>We could also define error handling for errors relating to message
> >>size, if needed.
> >>
> >>Regards,
> >>Yoshihiro Ohba
> >>
> >>On Thu, Dec 14, 2006 at 06:03:56PM -0600, Michael.G.Williams@nokia.com
> >>wrote:
> >>>Yoshi,
> >>>
> >>>Thanks for tracking this. If possible, could we email a bit about it
> >
> >>>as it was something .11u was concerned about too.
> >>>
> >>>This value could be something configurable by the network operator
> >>>or mobile node provisioner. It could vary from operator to operator,
> >
> >>>and possibly vary under other circumstances such as authorized vs.
> >>>unauthorized use of the network, or even query to query.
> >>>
> >>>So if the solution here can be something that is discovered, or
> >>>handled via error cases (i.e. the limit is provided in response to
> >>>an attempt to exceed it) that might provide the flexibility and the
> >>>constraints needed.
> >>>
> >>>Best Regards,
> >>>Michael
> >>>
> >>>
> >>>
> >>>-----Original Message-----
> >>>From: ext Yoshihiro Ohba [mailto:yohba@tari.toshiba.com]
> >>>Sent: Thursday, December 14, 2006 12:06 PM
> >>>To: Williams Michael.G (Nokia-ES/MtView)
> >>>Cc: STDS-802-21@LISTSERV.IEEE.ORG
> >>>Subject: Re: [802.21] Conference call tomorrow Dec 14th 9AM Eastern
> >>>Time US
> >>>
> >>>In today's telconf, I forgot to mention that I am working on:
> >>>
> >>>> 1.1.4. Limiting Response Message Length: Need a
> >>>>mechanism to limit the response length of a query.
> >>>>
> >>>Regards,
> >>>Yoshihiro Ohba
> >>>
> >>>
> >
>