Hi Michael,
I think the issue of TLV and XML was discussed during 802.21 meeting.
But it appears to me that more folks supported the idea of TLV in last
802.21 meeting. I guess there was straw poll as well. Do you have any
result of straw poll? It may be good data point about 802.21's view
about XML versus TLV.
Regards,
Ajoy
-----Original Message-----
From: mipshop-bounces@ietf.org [mailto:mipshop-bounces@ietf.org] On
Behalf Of Michael.G.Williams@nokia.com
Sent: Thursday, October 13, 2005 6:38 PM
To: Kempf@docomolabs-usa.com; yohba@tari.toshiba.com
Cc: mipshop@ietf.org; gabriel_montenegro_2000@yahoo.com;
rajeev@iprg.nokia.com; Petrescu Alexandru-AAP021
Subject: RE: [Mipshop] Re: Architectural Considerations for Handover
InformationServices (was: Re: CARD Discussion Query Discussion)
Colleagues,
A couple of points regarding the issue of chartering / standardizing for
FMIP needs, and getting .21 & MIPSHOP to work together...
We are at the draft stage in 802.21 and need proposals to modify the
draft.
.21 is counting on the solution in the IETF to be
compatible/interoperable with the IEEE solution. Sorry to be so high
level on that statement.
.21 requires an IS solution that solves problems for more than just
FMIP.
Perhaps the issues of IE representation and query language can be
separated to some degree? For example, if an alternative query language
exists today that would be useful, could it be used against the XML
representation?
.21 has expressed needs for extensibility and flexibility. The approach
of schemas and dynamic semantic agreements is one way to enable those
traits.
The issues of bandwidth & latency have been raised in both fora, but do
we have the empirical support for both sides of the issue?
Best Regards,
Michael
-----Original Message-----
From: mipshop-bounces@ietf.org [mailto:mipshop-bounces@ietf.org] On
Behalf Of ext James Kempf
Sent: Thursday, October 13, 2005 3:58 PM
To: Yoshihiro Ohba
Cc: mipshop@ietf.org; gabriel_montenegro_2000@yahoo.com; Rajeev Koodli;
Petrescu Alexandru-AAP021
Subject: [Mipshop] Re: Architectural Considerations for Handover
InformationServices (was: Re: CARD Discussion Query Discussion)
It is obviously more hard and inefficient for the client to process
high volume of raw data provided by the networks to extract a piece of
information in which the mobile is interested and choose an
appropriate network, than to construct a semantic query to retrieve
only necessary information it is really interested in. The raw data
can be order of hundred kilobytes if there are 10 MAC types each has
20 or more neighboring point of attachments each advertising hundreds
of bytes of information and most of the data could be just garbage and
for the client and it is wastful in terms of both bandwidth and
processing resources. If the mobile is moving at a high-speed, then
information on "neighbors of neighbors" needs to be obtained to
proactively make handover decisions, then the information volume can
be more.
But at 100 Mbps (802.11n speed) 100K is just 1 msec. Even at 11 Mbps,
its still only 100 msec. if there's no contention for the link. It's
just not a problem with today's bandwidths, IMHO. We're not talking
about 9.6 kbps links anymore. And I'm not saying that there should be no
query language, just that it should be simple.
Since I don't think typical users want to be bothered with specifying
the details of querying for handover services information, it seems
that automatic query construction would be required. Most users want
some kind of symbolic or summary information, if they need to be
involved in an intertechnology handover decision.
I believe automatic query construction can be made for any query
methods.
Well, I know (from having implemented it with SLP) that it is hard. It
is much easier to haul over what you need and process it locally. What
happens is the query typically ends up getting stuff you don't want
anyway, regardless of how careful you are in constructing it, so you
typically need to postprocess anyway. So why bother to have all the code
and complexity of trying to do the automatic query construction?
Application developers then don't bother to use the complex query
language, so you end up having this substantial chunk of code in the
protocol processing that isn't used most of the time.
It is much easier to just ask for the available information, then do
the processing on the client. I can't see the amount of information
on handover services being so large that it would be unreasonable to
send over the wireless link, especially given the trend toward
increased bandwidth.
I actually mean "using complex query semantics" not "full text".
Systems
with complex query semantics in the network haven't been very
successful in the network information services area. For example,
DNS has very simple query semantics. LDAP has very complex query
semantics. People prefer DNS.
Query semantics is naturally not the only reason why they prefer
DNS, of course, but having complex query semantics has not proved
such a compelling attraction to motivate people to use LDAP for
directory services instead of DNS (though LDAP was for a time
considered to be a possible successor to DNS). There are other
examples I could cite, and I don't think we need to get into a
debate here about this particular example. For this reason, I
believe that having a simple query semantics, using keywords or the
like, is a better solution than complex queries.
I believe a solution depends on the detailed requirements on the
service provided by it, not directly on the area the service belongs
to.
I'm not sure I understand your point. What do you mean by "the area
the service belongs"?
I mean the area of network information services.
BTW, I think this kind of discussion should be done in 802.21 where
Information Service for heterogenious handovers is being defined.
No, it needs to be done here too. You're claiming that you want an XML
protocol with complex query language. I disagree, based on my experience
with SLP and LDAP, that this is really any value in a system-level
application like network information services. Regardless of what 802.21
wants, we need something that provides network information for FMIP, and
if we are going to try to get the two applications to work together, we
need to come up with a protocol that satisfies both.
Anybody else have an opinion?
jak
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