Picking up on one of Ajay's comments regarding
implementation specific issues (AAA & Policy), this
is what we hope to address within the WIEN group
of IEEE 802.11. There is some 'fine detail' that
needs to be addressed when trying to interwork with
You are also welcome to come along and see what we
I also intend to make a presentation within IEEE 802.21
to clarify the scope of the WIEN activities.
> -----Original Message-----
> From: Ajay Rajkumar [mailto:ajayrajkumar@LUCENT.COM]
> Sent: Wednesday, April 14, 2004 3:20 PM
> To: Reijo Salminen
> Cc: 'Johnston, Dj'; stds-802-21
> Subject: Re: 802.21
> Let me say at the outset that you are most welcome to
> participate in the working of 802.21. IEEE operates on
> membership at an individual level rather than company based.
> Every participant is a member of the WG, though there are
> very specific IEEE attendance rules to acquire voting membership.
> At this stage of 802.21 working, the emphasis would be on
> participation and constructive ideas to solve the problem of
> Seamless Media Independent Handover.
> Regarding your concern about the complexity of cellular
> systems as opposed to 802.xx systems, I am not so sure. The
> main difference between the 802.xx systems and various
> cellular systems is that 802.xx primarily defines the MAC/PHY
> layer specification, whereas, cellular systems not only
> define the MAC/PHY of the air-interface but the whole network
> architecture as well, end-to-end.
> But at the same time, if one tries to take a larger view, we
> in 802.21 are not talking about going into the inner workings
> of cellular MAC/PHY but stay above that. For example, one
> possible idea that has gained traction is Layer 1/2 triggers,
> which could facilitate timely/informed handover decisions.
> Obviously, a handover decision would still have to be made by
> some higher level entity.
> Again, issues related to Authentication, Authorization, and
> Accounting (AAA) as well as QoS under different
> air-interfaces and networks would play a role. My personal
> feeling is that some of these issues are more implementation
> related and others would have to be dealt with at a policy level.
> Besides the above, the impact of your point regarding "legal
> interception" would have to be understood more clearly. I may
> just add that here the emphasis is on fast handover
> (make-before-break wherever overlap exists) otherwise
> protocols such as Mobile IP perform fairly well in
> heterogeneous networks.
> I would like to cc this email to the larger group through the
> 802.21 reflector, so that others in the group can also
> participate in the discussion.
> Let me know if you plan to give a presentation so that I can
> schedule you on the agenda.
> Chair, IEEE 802.21
> On 4/14/2004 9:14 AM, Reijo Salminen wrote:
> > Ajay, David
> > Since the next 802.21 meeting is not too far away in the
> future, and
> > in case I will be allowed to present my ideas in the meeting (and
> > hopefully be considered as qualified member to participate in the
> > work), I would need an indication for that, since to
> prepare a proper
> > presentation would take some time for me and is as you know
> quite an
> > effort anyway.
> > Some words about my background - I've been involved in the
> > of different cellular systems - NMT, GSM (from the beginning), PDC
> > (aka Japanese Digital - in HLR and MSC), WCDMA (in core
> network level,
> > MSC server, MGw and in RAN level and RNC L2 user plane),
> all these in
> > different roles from design to product management, and before the
> > cellular systems I have been working on transmission systems and
> > speech processing, and have done research on digital video systems.
> > These all in different companies here in Europe.
> > What I tried to say in my previous mails need a bit more
> > clarification, and I try to explain a bit more here.
> > I understand that it is a very natural thing to try to integrate
> > different communication systems (even wired, but mainly
> wireless) by
> > using handovers between the systems, and as you have stated
> it is not
> > too difficult to be done in the IP and 802.xx 'world' systems. But
> > when the cellular systems come into the picture the
> situation will be
> > somewhat different, I'm afraid. If you look at the TS'es of
> 3GPP you
> > get an understanding what I mean. You have also raised in your
> > meetings the question about how to handle security and
> > in connection to the handovers between arbitrary networks
> > - that is definitely a challenge, as will be the legal
> interception that I
> > mentioned in my earlier mail. Also it should be kept in
> mind that increased
> > complexity will always mean lower in-service performance
> and higher cost of
> > ownership of the systems, this is a lesson that has been
> learned the hard
> > way in the cellular world. Also it can be difficult to find
> the needed level
> > of expertise to be able to handle the technical detailed
> questions that
> > arise when the mobile host is performing handovers between
> different systems
> > - and who will then take the responsibility if/when
> something goes wrong -
> > the consequences can be surprisingly big in the worst case.
> > What I'd propose to consider is to see the different networks (for
> > example 802.11x, 802.16, 802.20, UWB, GSM, GPRS, EDGE, CDMA, WCDMA,
> > CDMA-2000 etc) as 'components' and build additional
> functionality to
> > combine the needed 'components' into the heterogeneous
> system so that
> > the smallest amount of interworking impacts are caused to the
> > individual 'components'. This way it could also be possible
> to use the
> > different technologies in the way they have been intended
> to be used
> > and are optimized for. Also the cellular systems have quite well
> > working mobility management functionality which could be useful for
> > establishing the connections also in the heterogeneous network. So
> > what I mean is that it could be possible to let the mobile
> host have
> > the possibility to use any of the component networks
> (several of them
> > simultaneously if needed) if the heterogeneous network
> system is built
> > so that the needed additional (which is not very complex)
> support for
> > that in place. This would mean that the mobile host has the
> > controlling role in the traffic handling, once the network has
> > authorized the mobile host, this is somewhat in line if we look for
> > example how the mobile terminals have grown in functionality in the
> > cellular system generations versus what functionality is in the
> > network nodes. The common denominator to be used for decisions on
> > which of the components the mobile host would be using is
> then based
> > on the measured QoS (note I do not mean end-to-end QoS here), since
> > that indirectly includes very many different characteristics of the
> > radio links of the different access technologies. So at connection
> > establishment the QoS of the connection is required from the access
> > network, and if it can not be fulfilled, the mobile host initiates
> > establishment of another connection on another access network, and
> > when that is set up, the application using the connection
> is informed
> > about the situation and it can then perform the 'handover'
> (or maybe
> > better word in this context is 'swap') in the best suitable
> way, and
> > the old connection can be released.
> > There is a lot of details that would need to be explained by using
> > drawings and sequence diagrams, but hopefully you get the
> big picture
> > from this - if the 802.21 is done in this way then each of the
> > 'component' networks can be handled separately and the security etc
> > questions can be handled in more manageable way.
> > Comments/Questions?
> > Best Regards, Reijo Salminen
> > -----Original Message-----
> > From: Ajay Rajkumar [mailto:email@example.com]
> > Sent: 29. maaliskuuta 2004 17:16
> > To: Reijo Salminen
> > Cc: 'Johnston, Dj'; Ajay Rajkumar
> > Subject: Re: 802.21
> > Reijo,
> > I have been traveling ever since I came back from IEEE meeting in
> > Orlando. I am currently in UK, but would be back in my
> office by the
> > end of the week. Will respond to your email then, if you do
> not mind.
> > -ajay