Subject: RE: [Mipshop] Re: Media-Independent is IP

From: "Gupta, Vivek G" <[email-masked]>
Date: Mon, 17 Oct 2005 06:00:03 -0700

>
>I agree that upgrading existing L2 infrastructure may take long time.
>So the above remark makes me think that 802.21 tries to avoid that.
>Speaking of which, am I right to think that 802.21 will not define
anything >going into hardware?  I'm currently used to think that 802.11b
is a >hardware card, 802.11a another card and 802.16e/WiBro probably yet
another >card.
>
>Do you think there will be such 802.21 cards?  Or is it that 802.21
will >only be software?

802.21 is currently identifying and recommending specific amendments for
802.11 and 802.16 specifications. Some of these proposed changes are
likely to be in hardware. 
So in future you might see an 802.11 a/b/g/n card that may have 802.21
capabilities. Similarly for 802.16 as well.

Best Regards,
-Vivek

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of Alexandru Petrescu
Sent: Monday, October 17, 2005 4:58 AM
To: [email-masked]
Cc: [email-masked]; [email-masked]; Alexandru Petrescu
Subject: Re: [Mipshop] Re: Media-Independent is IP

Greg Daley wrote:

> Hi Alex,
> 
> Please bear with me while I try to provide some opinions.
> 
> Firstly, media independence is not (only) IP, it can be gained 
> somewhat using ethertypes etc.
> 
> That said, I think I understand your thought.
> 
> Alexandru Petrescu wrote:
> 
>> Dear all,
>> 
>> I personally perfectly understand the necessity of inter-access 
>> handoffs happening at L3 layer, by L3's defnition itself and by 
>> "media-independent" name.
>> 
>> What I don't understand is the following:
>> 
>> -why doesn't 802.21 do first L2 handovers between .11, .15 and .16 
>> exclusively, w/o IP.  That first, later we'll see.
> 
> 
> There's potentially a long lead time for these things, and in some 
> cases, a lot of deployed hardware.

It would be a good exercise to define prototype and deploy a hand-over
between 802.11 and 802.16, with MAC only.  That would give a good
definition of 'hand-overs'.

> Sometimes it's not appropriate to upgrade the L2 infrastructure even
>  if the edge (phones/laptops) are regularly upgraded.

I agree that upgrading existing L2 infrastructure may take long time.
So the above remark makes me think that 802.21 tries to avoid that.
Speaking of which, am I right to think that 802.21 will not define
anything going into hardware?  I'm currently used to think that 802.11b
is a hardware card, 802.11a another card and 802.16e/WiBro probably yet
another card.

Do you think there will be such 802.21 cards?  Or is it that 802.21 will
only be software?

>> -why doesn't 802.21 try to BoF first.  BoF is a common procedure at
>>  IETF.  Provided a critical mass is contributing, things can go 
>> relatively fast.
> 
> I think the original intention was to look at a BoF (and one was 
> proposed for last IETF), but information services were already under
>  consideration for MIPSHOP, and it was determined only one effort 
> should occur.

Ok.

>> -why the architectural trait "dumb network" is not followed for L3
>>  handovers.
> 
> 
> If you look at DNA, the dumb network assumption is alive and well.

Ok.

> There are a number of areas where existing approaches are known to be
>  limited.
> 
> Link-layer scanning and discovery are the primary cause of delay in 
> IPv6 handover if a combination of 
> Opti-DAD/DNA/FMIPv6/HMIPv6/MobileIPv6/OMIPv6/EBU etc. are deployed 
> (pick an appropriate subset).
> 
> 802.11 handover (scanning and probing) delays account for >90% of 
> handovers in some cases.
> 
> Intelligent (rather than dumb) network services are a way of 
> delivering ifnromation which can solve this.

I don't think that the scanning and probing time can be reduced by using
IP message exchanges, because IP messages can be exchanged only when L2
is up.  Do you think that the scanning and probing time can be reduced
by using IP message exchanges?  Or do you think that that time will be
eliminated entirely?

> If we can get to a way of doing it well which is fairly dumb, that 
> would be great.  There may still be value in using intelligence where
>  it is available though.

Right, I share that view, use intelligence where it's available.

>> -why local L2-triggers are needed for fast mobility, and at the 
>> same time fast mobility is not needed for 802.21 which in turn 
>> needs to encode L2-triggers.
> 
> Link-layer indications are already required for FMIPv6 and DNA. 
> Otherwise you don't know to react quickly.

Some current emails mention that 802.21 does not target doing faster
handovers.

Link-layer indications required by FMIPv6 are local, on same machine,
not Services from network.

Does 802.21 have a precise idea of what are those local link-layer
indications in the particular case of 802.11b?  Can one use that as
starting point.

Alex

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---

From: Alexandru Petrescu <[email-masked]>
Date: Mon, 17 Oct 2005 16:15:59 +0200

Gupta, Vivek G wrote:
>> I agree that upgrading existing L2 infrastructure may take long 
>> time. So the above remark makes me think that 802.21 tries to avoid
>>  that. Speaking of which, am I right to think that 802.21 will not 
>> define
> 
> anything >going into hardware?  I'm currently used to think that 
> 802.11b is a >hardware card, 802.11a another card and 802.16e/WiBro 
> probably yet another >card.
> 
>> will only be software?
> 802.21 is currently identifying and recommending specific amendments 
> for 802.11 and 802.16 specifications. Some of these proposed changes 
> are likely to be in hardware. So in future you might see an 802.11 
> a/b/g/n card that may have 802.21 capabilities.

Thanks, that is good to know.  That means no special 802.21 cards, just
802.21 capabilities in new 802.11 cards.  I may also think that in the
future I may be able to see 802.11abgn cards that may have 802.11u and
802.11k capabilities, that are also recommendations to 802.11.

802.11u: inter-working with non-802.11 networks.
802.11k: radio measurement data to be exchanged between AP and STA,
         for load balancing a terminal to other networks.

Do you think that 802.11u and 802.11k are competitors to 802.21?

> Similarly for 802.16 as well.

I was thinking that 802.16 connectivity STA to BS is fundamentally
different than 802.11, from IP perspective, in that 802.16 is using some
form of point-to-point serial link, ppp maybe.  So I was thinking that a
same terminal card could not run both .11 and .16.  I was thinking that
a 802.16 interface in linux would be called "eth0" and the 802.11
interface called "ppp0".

IP runs differently over eth0-like interfaces than on ppp0 interfaces,
with respect to ARP and ND (no ND/ARP over ppp0).

Alex

---

From: Greg Daley <[email-masked]>
Date: Tue, 18 Oct 2005 09:19:24 +1000

Hi Alex,

[cut]
> with respect to ARP and ND (no ND/ARP over ppp0).

Actually, IPv6 Router Discovery can still be used, and DAD is needed
where autoconfigured addresses are used on PPP interfaces.

So while that assumption works with the link-layer address of the
peer, we're not working in IPv4-land anymore where a host can
only have one address.

Greg