Hi guys,

I hope there isn’t a confusion between draft-ietf-ondemand-mobility and 
draft-moses-dmm-dhcp-ondemand-mobility.


·        Draft-ietf-ondemand-mobility defines the ability of the network to 
provide different types of session continuity services and extends the Socket 
interface to enable application to influence the service they require for the 
newly established IP session. It does not specify how the session continuity 
requirements are conveyed to/from the network.


·        Draft-moses-dmm-dhcp-ondemand-mobility is the draft that defines 
extensions to DHCPv6 in order to convey session-continuity service type to the 
network.

Lorenzo,
I the last F2F in Seoul, you expressed your concerns that the proposed DHCP 
extensions to enabling the specification of the service type in IP address 
requests, contradict the recommendations specified in RFC 7934. As I mentioned 
in the discussion, I am committed to fix the wording in that draft to resolve 
that contradiction.

But draft-ietf-ondemand-mobility discusses extensions to the Socket interface. 
Sockets are used by application developers to initiated IP sessions. I do not 
think application developers should be networking experts and should be aware 
of what is being allocated by cellular networks to mobile hosts (or UEs, in the 
3GPP jargon…). This draft does not indicate that each invocation of a socket 
API to initiation an IP session, results in a request to the network. It does 
not get into these resolutions intentionally. We are separating the description 
of what an application does, to what the mobile host’s IP stack does.

Therefore, I do not think we should confuse application writers with IP 
prefixes. All they need to know is how to influence the service that are 
getting, like their ability to choose between a reliable transport (TCP) or 
unreliable one (UDP).

I hope you agree with this separation.

Thanks and regards,
Danny

From: Peter McCann [mailto:peter.mcc...@huawei.com]
Sent: Friday, December 02, 2016 22:37
To: Lorenzo Colitti <lore...@google.com>
Cc: jouni.nospam <jouni.nos...@gmail.com>; 
draft-ietf-dmm-ondemand-mobil...@ietf.org; dmm@ietf.org
Subject: RE: [DMM] WGLC for draft-ietf-dmm-ondemand-mobility-08

Agree, I am not arguing in favor of sharing a prefix between two or more MNs at 
the same time.  However, I think it is important to reclaim a prefix for use by 
another MN after the current MN has moved to a new attachment point and stopped 
using the prefix it got from the old attachment point.   It is also important 
to refrain from advertising the prefix to another MN until the current MN has 
stopped using it.  That is the network state I am talking about.

-Pete


From: Lorenzo Colitti [mailto:lore...@google.com]
Sent: Friday, December 02, 2016 3:32 PM
To: Peter McCann <peter.mcc...@huawei.com<mailto:peter.mcc...@huawei.com>>
Cc: jouni.nospam <jouni.nos...@gmail.com<mailto:jouni.nos...@gmail.com>>; 
draft-ietf-dmm-ondemand-mobil...@ietf.org<mailto:draft-ietf-dmm-ondemand-mobil...@ietf.org>;
 dmm@ietf.org<mailto:dmm@ietf.org>
Subject: Re: [DMM] WGLC for draft-ietf-dmm-ondemand-mobility-08

On the particular case of shared links: note that they have substantial 
scalability and performance issues. In order for shared links to work you have 
to engage in DAD proxying, ND snooping, client isolation and all sorts of 
unsavoury and L2/L3 magic that does not scale. Some of these issues are 
described in RFC 7934 section 9.3. On shared links, these forces act to reduce 
the number of IP addresses per host that the network can support and leads to 
the negative consequences in section 4 of the document, which is why they are 
not recommended.

For these and other reasons, on many public networks we're seeing a shift 
*away* from shared links - see, for example, 
draft-ietf-v6ops-unique-ipv6-prefix-per-host , and the current large 
deployments of that model in the form of Comcast community wifi.

For many years 3GPP networks have been providing those benefits by providing a 
full /64 to every host. I would hate to lose those benefits.

On Fri, Dec 2, 2016 at 12:12 PM, Peter McCann 
<peter.mcc...@huawei.com<mailto:peter.mcc...@huawei.com>> wrote:
With a fixed access network the prefix can be assigned to the link and used by 
anyone who joins the link.

With a prefix offering mobility the prefix belongs to the mobile host and needs 
to move with it.  There aren’t enough prefixes (even in IPv6) to assign a 
permanent prefix to each UE for every topological attachment point that it 
might visit or start a session from.

-Pete


From: Lorenzo Colitti [mailto:lore...@google.com<mailto:lore...@google.com>]
Sent: Friday, December 02, 2016 3:09 PM
To: Peter McCann <peter.mcc...@huawei.com<mailto:peter.mcc...@huawei.com>>
Cc: jouni.nospam <jouni.nos...@gmail.com<mailto:jouni.nos...@gmail.com>>; 
draft-ietf-dmm-ondemand-mobil...@ietf.org<mailto:draft-ietf-dmm-ondemand-mobil...@ietf.org>;
 dmm@ietf.org<mailto:dmm@ietf.org>

Subject: Re: [DMM] WGLC for draft-ietf-dmm-ondemand-mobility-08

But you have that problem with IP addresses as well, right? I don't see how 
"assigning a prefix with certain properties" requires more state in the network 
than "assigning an IP address with certain properties".

On Fri, Dec 2, 2016 at 12:00 PM, Peter McCann 
<peter.mcc...@huawei.com<mailto:peter.mcc...@huawei.com>> wrote:
Providing any kind of mobility service for a prefix will require some state 
somewhere in the network.  It would be great to avoid an allocation request / 
response for the prefix, but the state has to be created somehow before the UE 
can use the prefix and it has to be reclaimed eventually after the UE stops 
using the prefix (which may not be until well after it disconnects from the 
current link and moves to another one).

Would welcome any suggestions on how to manage this state.

-Pete


From: dmm [mailto:dmm-boun...@ietf.org<mailto:dmm-boun...@ietf.org>] On Behalf 
Of Lorenzo Colitti
Sent: Friday, December 02, 2016 12:04 PM
To: jouni.nospam <jouni.nos...@gmail.com<mailto:jouni.nos...@gmail.com>>
Cc: 
draft-ietf-dmm-ondemand-mobil...@ietf.org<mailto:draft-ietf-dmm-ondemand-mobil...@ietf.org>;
 dmm@ietf.org<mailto:dmm@ietf.org>
Subject: Re: [DMM] WGLC for draft-ietf-dmm-ondemand-mobility-08

Hi,

I like the goal of reducing network cost by allowing the use of IP addresses 
that do not require network mobility, but we should not be doing this by 
requesting IP addresses from the network, because this violates IPv6 address 
assignment best practices.

Specifically, RFC 7934 recommends that a) the network should provide multiple 
addresses from each prefix and b) the network should allow the host to use new 
addresses without requiring explicit requests to the network. This is in 
conflict with at least this text in the draft, which says:

   In case an application
   requests one, the IP stack shall make an attempt to configure one by
   issuing a request to the network.  If the operation fails, the IP
   stack shall fail the associated socket request

One way to resolve this conflict would be to say that the network must not 
assign individual addresses, but /64 (or shorter) prefixes. So if the device 
desires to use fixed IPv6 addresses, then the network should give the host a 
fixed IPv6 prefix from which the host can form as many addresses as it wants.

I do not think we should advance this document until the conflicts are 
resolved. This document is about IPv6 address assignment to mobile nodes, and 
we should not publish a document about IPv6 address assignment that conflicts 
with best current practices on IPv6 address assignment.

Regards,
Lorenzo

On Mon, Nov 28, 2016 at 12:56 PM, jouni.nospam 
<jouni.nos...@gmail.com<mailto:jouni.nos...@gmail.com>> wrote:
Folks,

The authors of draft-ietf-dmm-ondemand-mobility-07 and 
draft-sijeon-dmm-use-cases-api-source have come up with a merged document 
draft-ietf-dmm-ondemand-mobility-08.

This email starts a 2 week WGLC for draft-ietf-dmm-ondemand-mobility-08.
The WGLC starts 11/28/16 and ends 12/12/16.

Provide your comments, concerns and approvals to the email list (and hopefully 
also to IssueTracker).

- Jouni & Dapeng



Begin forwarded message:

From: IETF Secretariat 
<ietf-secretariat-re...@ietf.org<mailto:ietf-secretariat-re...@ietf.org>>
Subject: IETF WG state changed for draft-ietf-dmm-ondemand-mobility
Date: November 28, 2016 at 12:51:34 PM PST
To: 
<draft-ietf-dmm-ondemand-mobil...@ietf.org<mailto:draft-ietf-dmm-ondemand-mobil...@ietf.org>>,
 <dmm-cha...@ietf.org<mailto:dmm-cha...@ietf.org>>, 
<max....@alibaba-inc.com<mailto:max....@alibaba-inc.com>>
Resent-From: <alias-boun...@ietf.org<mailto:alias-boun...@ietf.org>>
Resent-To: jouni.nos...@gmail.com<mailto:jouni.nos...@gmail.com>, 
maxpass...@gmail.com<mailto:maxpass...@gmail.com>


The IETF WG state of draft-ietf-dmm-ondemand-mobility has been changed to
"In WG Last Call" from "WG Document" by Jouni Korhonen:

https://datatracker.ietf.org/doc/draft-ietf-dmm-ondemand-mobility/


Comment:
WGLC starts 11/28/16 and ends 12/12/16.


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