[DMM] Comments on draft-patil-dmm-issues-and-approaches2dmm-00

[Peter McCann <[e-mail]>]

Hi, Raj, Carl, and Jouni,

I have some comments on draft-patil-dmm-issues-and-approaches2dmm-00.

I agree with most of Section 4, "Issues with current mobility models".  However,
I'd like to point out that existing networks are not just centralized in the manner
you point out, they also tend to have a hierarchical structure, e.g., the 
S-GW/P-GW split in 3GPP EPC.  Therefore, the issue you outline in Section 4.3
("Inefficient Routing and signaling overhead") is not quite true of the 3GPP
EPC, which can handle many mobility events in a localized manner similar to
HMIP.

The first paragraph of Section 7 talks about source address selection, and the
need to modify applications so that they request the kind of address that they
want.  I tend to think that applications will remain unmodified for some time
to come; however, most applications fit into the paradigm of opening short-lived
connections to a server and could be accommodated with some sort of automatic
handling in the MN's IP stack.

I found the last paragraph of Section 7 quite interesting.  I too think that there
is an important piece missing that you call "seamless mobility anchor relocation".
I think that the use of an interior routing protocol is spot on.  In fact, if you
read draft-mccann-dmm-flatarch-00, I propose just that.  I think we can use such
an anchor relocation protocol to make each access router in an autonomous system
(or smaller region of an autonomous system) a temporary anchor for a given prefix.
In my draft I propose running I-BGP on each AR and sending BGP UPDATES into the
network upon localized mobility events.  Such a protocol can also be used as a
substitute for the proxy ND technique that is currently specified to "grab" the
MN's packets at the HA.  By using a routing protocol, the HA can reach across
several routing hops so it doesn't necessarily need to be on the home link (which
can be the first AR to which the MN attached).  I think this would also enable us
to unify the authentication protocols used at the AR with the authentication protocol
used at the HA.  The ARs are just like HAs that don't have to tunnel the data anywhere
because the MN is locally connected.

Does it make sense to you?

--
Peter J. McCann
Huawei Technologies (USA)
[e-mail]
[phone]
Rm. C-0105, 400 Crossings Blvd. (2nd floor), Bridgewater, NJ  08807-2863  USA