Subject: Re: [netlmm] I-D Submission: draft-sgundave-mip6-proxymip6-01.txt

From: Behcet Sarikaya <[email-masked]>
Date: Tue, 9 Jan 2007 09:51:44 -0800 (PST)

Hi Sri,
Nobody is commenting, let me comment.
-What happened to giaddr?
-I think that per-MN prefix is not an option on the home link as per draft-iab-multilink-subnet-issues-02.txt?

Regards,

--behcet

----- Original Message ----
From: Sri Gundavelli <[email-masked]>
To: netlmm <[email-masked]>
Sent: Tuesday, January 9, 2007 11:14:07 AM
Subject: [netlmm] I-D Submission: draft-sgundave-mip6-proxymip6-01.txt

FYI.

A New Internet-Draft is available from the on-line Internet-Drafts
directories.

         Title : Proxy Mobile IPv6
         Author(s) : S. Gundavelli, et al.
         Filename : draft-sgundave-mip6-proxymip6-01.txt
         Pages : 39
         Date : 2007-1-5

This specification describes a network-based mobility management
    protocol.  It is called Proxy Mobile IPv6 (PMIPv6) and is based on
    Mobile IPv6.  This protocol is for providing mobility support to any
    IPv6 host within a restricted and topologically localized portion of
    the network and with out requiring the participation of the host in
    any mobility related signaling.

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---

From: Sri Gundavelli <[email-masked]>
Date: Tue, 9 Jan 2007 09:58:31 -0800 (PST)

Hi Behcet,

The draft has support for both the addressing models
and with the corresponding node configuration procedures.

1. Per-MN-Prefix: DHCP, Stateless Auto Address Config

2. Shared-Prefix: DHCP

There is a section on the interaction of the DHCP Relay
Agent and the Proxy Mobile Agent. In that section, we
have covered on the specifics of how the link-address
option (DHCPv6) or the giaddr field (DHCPv4) needs to
be set. That has to be set to the mobile's home prefix
and the DHCP server will allocate an addres from that
prefix block.

Sri

---

From: "Templin, Fred L" <[email-masked]>
Date: Thu, 11 Jan 2007 12:25:58 -0800

Hi Sri,

I haven't had time to read the draft yet, but hope to soon.

> and the DHCP server will allocate an addres from that

Why does link-address have to contain the MN's home prefix?
If I read RFC3315 correctly, link-address only needs to contain
a prefix that identifies the link, and that can be distinct from
the MN's home prefix. For that matter, the relay could instead
include an Interface-Id option and write '0' in link-address.

The DHCP server should be able to discover the MN's home prefix
by examining the Client Identifier, and w/o having to be told
anything by the relay.

Fred
[email-masked]

---

From: Sri Gundavelli <[email-masked]>
Date: Thu, 11 Jan 2007 13:03:03 -0800 (PST)

Hi Fred,

> include an Interface-Id option and write '0' in link-address.

As mentioned in Section 20.1.1 [3315], the relay agent sets this
field "with a prefix assigned to the link on which the client
should be assigned an address in the link-address field". In
Proxy Mobile IPv6, in the per-mn-prefix model, the mobile's home
prefix is hosted on that access link and that is the prefix
block from which the DHCP server has to allocate an address.
Client Identifier is typically a node's MAC address and unless
the DHCP Server is provisioned with all the MAC addresses and
prefix of the PMIP6 nodes, the DHCP server cannot allocate an
address from their respective prefix blocks. The Relay agent
has to set some option that reflects the mobile's home prefix
and in DHCPv6, its link-address option.

Regards
Sri

---

From: "Templin, Fred L" <[email-masked]>
Date: Thu, 11 Jan 2007 13:36:39 -0800

Sri,
 
> prefix of the PMIP6 nodes,

Here is where my knowledge of operational aspects of cellular
infrastructures is lacking. Won't it be the case that per-MN
information will be accessed in the AAA before any addresses
are assigned? Then, why can't the MN's MAC address, home prefix,
etc. come from that initial exchange?

Also, the Client Identifier contains a DUID which may include
a MAC address - but other types of DUIDs are available and/or
can be defined. If there is some other type of identifier for
a MN that would aid the relay/server in performing the initial
exchange, then maybe we should petition for a new DUID type
for DHCPv6?

Maybe the crux of my question is why does the relay have to
convey anything to the server? Why can't the server discover
the per-MN information on its own?

Fred

---

From: Sri Gundavelli <[email-masked]>
Date: Thu, 11 Jan 2007 14:11:23 -0800 (PST)

Hi Fred,

> the per-MN information on its own?

This  is probably a question for the DHCP WG. This is the
normal expected behaviour of a DHCP relay agent, it has to
hint the DHCP server, the prefix block that it needs to use.
There is no deviation from the expected relay agent behaviour.
It is possible DHCP server can identify the mobile and allocate
an address from its prefix. But, from Mobile IP perspective,
the home agent has that intelligence, it is managing the binding,
it is the topological anchor point for that prefix, it holds
the mobile's roaming policies and so the rest of entities such
as a DHCP server need not build that home agent logic.

Some deployments may just provision the policy store with
just the mobile's MN-Identifier and the home agent MAY choose
to dynamically allocate the prefix after leazing it from the
DHCP server [Per 3633] and notify to the proxy mobile agent
in the Binding Ack, for it to host that prefix. DHCP server
can certainly do all this, but we are building on the Mobile IP
model.

Regards
Sri