Subject: RE: Paging Functional Architecture ( was: RE: [seamoby] L2/L3 Pag ing)

From: James Kempf <[email-masked]>
Date: Thu, 29 Mar 2001 14:39:36 -0800 (PST)

Yoshihiro,

>When we talk about power control mechanisms for wireline NIC cards,
>the wirelined host may not necessarily be a mobile node.  On the other
>hand, it seems to me that the paging discussed in this WG is tightly
>coupled with mobility (Mobile IP).  Is it out of scope to discuss a
>generic paging mechanism which can be used for both mobile and stable
>nodes?
>

I wouldn't say mobility, I would say routing. The kind of paging
we are looking at is concerned with getting a dormant mode host
to reestablish an active route back into the network. The problem
is most acute with mobile hosts because one can't simply depend
on the routes that were there before the host went dormant to be
valid.

With regard to a wired host, the Intel Wired for Management protocol
defines a kind of paging where a certain L2 frame causes a dormant
mode wired host to wake up (sorry, I don't know any more details).
One could view this as a kind of wired host paging. Note that it
is not sufficient to simply send a packet to the host because
the wakeup is triggered by a special L2 packet, if I am right about
the need for a special L2 frame. If it were the case
(as apparently it is with Bluetooth) that the host could be reawakened
without any special protocol, then one could simply send the packet
and let the host wake up to take it. No paging protocol is needed
in this case.

		jak

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From: Yoshihiro Ohba <[email-masked]>
Date: Fri, 30 Mar 2001 16:15:03 -0500

At Thu, 29 Mar 2001 14:39:36 -0800 (PST),
> on the routes that were there before the host went dormant to be

I agree with you on saying routing.

> the need for a special L2 frame. 

It is Magic Packet technology 
(http://www.amd.com/products/npd/overview/20212.html).

A Magic Packet could be any MAC frame (even a TCP/IP data frame could
be a Magic Packet), by inserting a special paging sequence specific to
the MAC address of the paged device.  (The sender of the packet must 
know the target MAC address.)

> If it were the case

When L2 paging is triggered by L3 packet, at least some mechansim is
needed for a paging agent to retain the mapping between MAC address
and L3 address for the dormant node.  The mechanism might be just 
lengthening the ARP/neighbor cache lifetime at the paging agent, or
an explicit paging registration mechanism.

I may be stepping into requirement phase...

Regards,
Yoshihiro Ohba

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From: Yoshihiro Ohba <[email-masked]>
Date: Fri, 30 Mar 2001 16:15:03 -0500

Regards,
Yoshihiro Ohba