Subject: [netlmm] Minutes from IETF 66

From: "James Kempf" <[email-masked]>
Date: Mon, 24 Jul 2006 13:09:40 -0700

Below, the minutes from the IETF 66 meeting. Please send comments by Fri.

            jak

--------------------------

NetLMM WG session,
Mon, 9:00am - 11:30am

Agenda:
 agenda bashing
 draft status
 SDO outreach
 Continued DT work and interim meeting
 DT protocol presentation
 MN-AR interface draft
 Security threats draft

---

draft status
<James>:
MN-AR draft: new author and added DHCP work
Clarification: DT drafts are starting point for WG draft.

---

SDO outreach
<James>:
3GPP - NetLMM presented at joint 3GPP SA1/SA2 meeting in Lisbon (June 2006)

---

Continued DT work
<james>:
DT will issue stable draft middle of Sept 2006.
Plan: 2 days interim meeting e.o. Sept.
<Phil>: Chicage has been proposed.
<James>: raise hands -> 16 want to come

---

DT draft presentation and discussion
<Kent Leung>: netLMM protocol overview (slides)
*Netlmm terms
*NetLMM domain overview
*NetLMM messages
*Message transport
 Lot of discussion in the DT. Input welcome. Result of debate was to use 
UDP.
*Message use at functional elements
*Detailed message types
 LMA allocation request/reply
 Associate request/reply
 Disassociate request/reply
 Location Registration/Ack
 Location Deregistration/Ack
 Routing Setup/Ack
<Dave Thaler> Prefix at MN or whole address at MN?
<James>  Please ask question later
 MN address setup/Ack
 MN Address Remove/Ack
 Heartbeat/Ack
*Error COdes
*Call Flow SCenarios
 Initial network access
 Stateful address assignment via DHCP
 SLAAC
 Multiple IP addresses via SLAAC
 IP address release notification
 inter-MAG handover (no CT)
 Resource Revocation
 DHCP renewal on new MAG
  associated packet en-/decapsulated between MAG and LMA
 IP Address no longer in use
  (only when known for sure)
  Maybe WG can help to define details
 Network detachment
 IP Multicast join groups
*Data flows
 Link-local multicast traffic
 Unicast traffic
 MN sourcing IP multicast traffic
 MN receiving IP multicast traffic
*Upcoming work items
*Summary

Input welcome/comments solicited

<Alex Petrescu>
Great work. Seems to be many messages (feedback already).
Errors in the DHCP messages. Prefix distribution LMA-MAG
Do you consider router re-numbering?
<Kent> So far not. Maybe TBD.
<Alex> Could be useful to implement.
<Kent> 'High level' is comment such as on DHCP, etc.
<Alex> Mobile network prefix distribution considered?
<Kent> Keep it flexible to support. Field allow prefixes

<Dave Thaler> Great overview. Question is whether each MN gets different 
prefix.
<Kent> Each MN could append different prefix.
<Dave> CAN or MUST different MNS receive different prefixes?
<Kent> Not MUST.
<Dave> Cleanest solution would be to keep it consistent to assign per MN
prefixes (?). LMA does not care about individual addresses.
<Kent> Agree that DAD is unreliable.
<James> Not solve this problem. Focus on mobility management, not on
how addresses are being done. Agree that cleanest solution is to
assign one prefix per MN. Strong concerns with this?

<Fred Templin> Stateless and stateful, only a MN issue. With DHCP, the MN 
can
also request a particular address, not that the DHCP in any case assigns the 
address.
DHCP server can be used to perform SLAAC.
<Kent> We'll look into this.

<Vidya Naryanan> Don't mandate a unique prefix per MN. Router Adverts are 
the same for
all MNs. Too many message. Looks too complicated.
<Kent> Many things optional.
<Vidya> I see that some functions are not required for mobility.
<Henrik Levkowetz> Now I understant your comment that some messages are just
not needed. Propose to put MSCs into the draft.
None of DT members wants to keep complicated signaling.
<Vidya> Mandating the MAG being default gateeway: I don't see a reason
to mandate. Fine to recommmend, but do not disallow that the LMA is the
default GW.
<James> Look at DNA. Bidirectional reachability to be confirmed.
<Vidya> I don't think that in 802 networks it makes sense to mandate
the MAG is the default gateway.
SLAAC: MAG is user agent.
<Kent> Natural that MAG is DHCP relay.
<Vidya> If there is more that one router, there is not only the MAG.
<Kent> Lots of discussion, MN can use any of these routers as default GW.
Then it triggers the serving MAG.
<Vidya> Routing Tags, not really required, since details are not really 
described.
<Kent> Is conceptual concept. We discussed to keep it out.
<Vidya> Heartbeat: Not every protocol should use heartbeats.
<Kent> We use UDP, which is not reliable.
<Vidya> Should be a soft-state protocol. Why not use Mobility Header?
Do you need reliability?
<Phil> DT discussed this also. This time after a debate we decided to
use UDP. WG comments solicited.
<Hesham Soliman> Heartbeat is orthogonal to the reliabilty discussion.
<James> Get a sense if WG thinks that NetLMM needs reliable transport -> 
more
want it reliable.
<Vidya> Heartbeat. What for?
<Henrik> Detect various failures. Node failure, Link failure.
<Vidya> Reachability of a network is beyond NetLMM. Should not be in the 
protocol.
<Kent> What do others think? With SCTP, you don't need to care. We found it 
useful.
<Phil> Maybe Vidya can poste a list of issues to the list. Easier to comment 
and
discuss
<Vidya> Yes.
<Hesham> SLAAC. DAD should be based on what? Where is the prefix?
<Kent> Prefix assigned in step#7. Comes from the LMA. MAG advertises.
<Hesham> If this prefix comes from DHCP? Can multiple MAGs share this 
prefix?
<Kent> Two different things. LMA assigns the prefix for the MN. Assumption 
is
multiple MNs on that prefix.
<Hesham> Can other MAGs use this prefix?
<Kent> Yes, since prefix is assigned to MN, not to MAG. MAG just advertises.
<Hesham> What about re-newing the prefix?
<Fred> Prefix travels around with the MN.
<Alex> Confusion: Prefix from DHCP is prefix delegation. This is different.
<James> Looks like this is about prefix delegation in stateless 
configuration.
<kent> All it does is to assign the prefix through the MAG.
<Fred> LMA default router, as Vidya proposes: Colocated case? Two functions 
on the
same box. In case multiple ARs on the link?
<Kent> MN decides which is default router (through NDP). Host side can have 
multiple
default routers.
<Dave> There is an RFC on that (Host Route Sharing from IPv6 WG).
<Kent> Then we need to support this mode of operation.
<Fred> Why is tunnel bi-directional?
<Kent> Debate on unidirectional vs. bi-directional.
<Henrik> You could do it with routing through dfferent LMAs. Depends on
policy.
<Kent> Issue is uni- vs bi-directional.
<James>  8 mins left. Then move to the next items.
<Alex> # of messages: Example address expiration, draft describes to tear
down the address. DHCP has no signaling on that. It just expires. Route
comes down automatically.
<Kent> No timer in NetLMM for addresses.
<Vidya> MAG and LMA share SA should be mandatoy.
<James> PS draft, comments from security AD. Requirement for NetLMM, routing
security issues can be given to other WG.
<Dave> Initial Network Access: Individual prefixes for MNs. Use DHCP prefix 
delegation
to ease protocol operation.
<Eric Njedjou> NetLMM address: How long is the address valid? What if MN 
moves to different MAG?
<Kent> Once MN has IP address, it stays as long as the MN is in the NetLMM 
domain.

---

MN-AR Interface
<Julien Laganier> MN-AR interface (slides)
*New author works on DHCP.
*Resolved issues.
*Unresolved issues.
*Biggest issue: Multiple ARs per link.

<Fred> Send DHCP messages to a specific L2 address. (?)
The one that the MN selected takes care about the MN.
<George Tsertis> You don't want MN to be involved in mobility. Why
to decide default router?
<Kent> MN can talk to other MN on the same link?
<Julien> Talk directly.
<Kent> Everything is on-link?
<Julien> It's off-link.
<Jounghoon> Two MNs on the same LMA (?)
<Julien> All ARs and LMA should decrement TTL.
<?> MN should select a router. Not that the MN can say I want router xyz.
<Fred> Disagree. MN can decide to use a particular AR.
<George> MN cannot choose the downlink.
<?> thought NeLMM is to completely hide everything. MN given
an IP address, that's it.
<James> Right.

---
Security threats
<James> Security threats (slides)
Overview of changes.

No solutions yet. Solutions should be in MN-AR draft.

<George> How to deal with impersonation attacks?
<James> So solutions here. Should be in MN-AR draft.

<Vidya> Unauthorized AR, Unauthorized LMA
(?)

<Alex> DHCP has some security. Can we use?

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