Subject: RE: [seamoby] draft-ietf-seamoby-paging-problem-statement-01.txt

From: "Karim El-Malki (ERA)" <[email-masked]>
Date: Mon, 19 Feb 2001 18:59:49 +0100

Hello James

> >>Unless the paging area and the subnet
> >> are exactly the same, and this is impossible to guarantee 
> in realistic
> >> deployments.
> >
> >Does this justify the need for IP paging?
> 
> 
> Yes, this was one key insight that came out of the paging design team.
> Paging areas may cover a much larger chunk of network topology than
> a subnet, so we cannot depend on MIP registration to handle tracking
> the mobile while it is in dormant mode, for radio protocols 
> that support
> paging.

Even if paging areas cover multiple subnets, at L3 we're interested
in tracking the subnet movement which we can do with MIP. Is L3 paging
meant to be a replacement of MIP for dormant MNs? 

From the draft:

"Standard Mobile IP requires the mobile node to actively listen for or
   solicit foreign agent or router advertisements and participate in
   registering, so it is of little use if the mobile is in dormant mode."

This assumes that when a node is in dormant mode it can't do MIP registrations,
therefore you need a new L3 paging protocol. We should not impose this
limitation on MIP's usage and the draft's definition of dormant mode does not
imply this:

"Dormant Mode - A state in which the mobile restricts its ability
      to receive normal IP traffic by reducing monitoring of radio
      channels. This allows the mobile to save power and reduces
      signaling load on the network."

Therefore a dormant MN would not receive normal IP traffic, but it could
send/receive Mobile IP signalling (over whatever radio channel is being
monitored).

On the whole I can't see why IP paging is needed for L2s which already have
L2 paging.

Regards,
/Karim