Re: [Mip4] Request to consider FMIPv4 as a working group document

[Alexandru Petrescu <Alexandru.Petrescu at motorola.com>]

[I have some comments on the draft, not the request itself, please
 disregard if already discussed or clarified.]

Espen Klovning wrote:
> I do have some concerns that more or less reflect what Kent Leung has
>  voiced in previous mails on the list. 
>- AR == FA
>- IP address management

I tend to agree with this.

The draft explains, but is not clear about what happens to FMIP when
CCoA/DHCP _is_ used.  If DHCP is _not_ used with FMIP then the draft 
should say so and in a coherent manner, IMHO; otherwise the generic 
"compatibility" statements confuse me at three points.

  "[First Scenario]: the access routers are not involved in IP address
   management for the MN. The mobile nodes acquire a new care-of address
   upon attaching to a new subnet link as they normally do."

In some deployments, MN normally acquires an address with DHCP and the
first-hop router is a DHCP Relay, so the AR practically _is_ involved in
IP address management for the MN, although the AR is not a DHCP Server.
 So the question coming to mind immediately is what is meant by "access
routers are not involved in IP address management for the MN"?  Does
that simply mean that AR is not a DHCP Server and is a DHCP Relay?

Second point is about DHCP and additional delays.  If vanilla DHCP is 
used then the effective DHCP delays are in the range 1s-10s with a 
802.11b WEP first-hop, 100Mbit Ether and GHz computers.  That is very 
large, easily influencing real-time.  It is not clear in the draft how 
any of these numbers influence FMIP - is FMIP slower if vanilla DHCP is 
used?

Third point is the apparent incoherence between abstract and body, with 
respect to DHCP.  The abstract says "For reducing the IP address 
configuration, the draft provides two alternatives" and none is DHCP. 
Or, later in the body one can read "Address allocation and configuration 
may be supported using DHCP or any other method."

Just some thoughts...

Alex

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