Internet DRAFT - draft-petrescu-netext-pmip-nemo
draft-petrescu-netext-pmip-nemo
NETEXT A. Petrescu
Internet-Draft M. Boc
Intended status: Informational C. Janneteau
Expires: January 12, 2013 CEA
July 11, 2012
Network Mobility with Proxy Mobile IPv6
draft-petrescu-netext-pmip-nemo-01.txt
Abstract
The Proxy Mobile IPv6 protocol supports Mobile Hosts moving
independently, but not Mobile Routers in charge of moving networks.
This draft addresses this problem. The goal is to allow
bidirectional communication between a Local Fixed Node (in the moving
network) and a Correspondent Node (situated arbitrarily somewhere in
the Internet). First, a mechanism of "prefix division" is presented,
whereby the Home Network Prefix typically assigned by PMIPv6 to a MH
is used by MR to form Mobile Network sub-Prefix(es); they are used by
LFNs within the moving network to form addresses; this avoids changes
in the PMIPv6 protocol specification. A second mechanism proposes
enhancements to the use of the DHCPv6 Prefix Delegation protocol
entities informing the PMIPv6 entities about the allocated MNP; this
is achieved by equaling MNID and DUID.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 12, 2013.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document.
Table of Contents
1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3
2. Concentrated Description . . . . . . . . . . . . . . . . . . . 4
2.1. HNP Division . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. DHCPv6-PD and PMIPv6 Enhancements . . . . . . . . . . . . 7
3. Security Considerations . . . . . . . . . . . . . . . . . . . 11
4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12
5. Normative References . . . . . . . . . . . . . . . . . . . . . 13
Appendix A. ChangeLog . . . . . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
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1. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
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2. Concentrated Description
The term Mobile Router has several meanings. One of the agreed
meanings at IETF, documented in terminology RFCs, is that of an
entity implementing the Mobile IPv6 protocol with NEMOv6 extensions,
and accomodating changes in its Care-of Address, maintaining a stable
Home Address with the help of a Home Agent, and in charge of LFNs in
a moving network whose addresses do not change. Another meaning is
that of a router which moves around and does not necessarily change
its IP address. In the context of this draft we consider this latter
meaning. We ignore whether or not the MR runs Mobile IPv6.
The work presented in this draft is developped in the context of
Proxy Mobile IPv6 [RFC5213]. With respect to prefix division,
similar methods have been alluded to in the context of DHCPv6 Prefix
Delegation by [I-D.krishnan-intarea-pd-epc] (with a slide
presentation in the DHC WG at IETF77) and of OSPFv3 by
draft-arkko-homenet-prefix-assignment-01.
Mechanisms for supporting Mobile Routers with PMIPv6 and DHCPv6 are
presented in [I-D.ietf-netext-pd-pmip] and preceding individual
drafts.
The methods presented in this draft are different from most if not
all existing documented methods to accomodate moving networks with
PMIPv6. In particular, the HNP Division offers several MNPs for use
by LFNs, does not modify PMIPv6, does not require the use of
DHCPv6-PD but has an inconveninent in that it may not accommodate
Ethernet LFNs with SLAAC. The DHCPv6-PD and PMIPv6 enhancements
offer MNPs potentially completely different than HNP, may use
Ethernet LFNs with SLAAC, modify MAG, LMA, DHCP Relay and potentially
DHCP Server.
Moreover, the PMIPv6 and DHCPv6 enhancements presented in this draft
rely on the use of MNID being equal to the DUID, a feature absent
from existing proposals. Also, with this mechanism the entity
performing the allocation of an MNP is the DHCPv6 Server (and not the
LMA).
2.1. HNP Division
The mechanism "HNP Division" divides the Home Network Prefix into two
or more Mobile Network Prefixes (MNPs).
It is assumed that in a domain running PMIPv6 the LMA assigns a Home
Network Prefix (HNP) to the Mobile Host. If we consider this Mobile
Host to be a Mobile Router, in charge of a set of Local Fixed Nodes
(LFNs) in a moving network, it is necessary to use a Mobile Network
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Prefix (MNP) within the moving network. Simply using HNP to form
addresses for LFNs, without modifying MR behaviour with respect to
its routing table, is not sufficient.
The topology illustrated in the next figure depicts a domain where
PMIPv6 is run, and a Mobile Router in charge of a set of LFNs forming
a moving network.
----
| CN |
----
|
Internet
|
----
| LMA|
----
|
Operator Network
/ \
/ \
---- ----
|MAG1| |MAG2|
---- ----
| HNP
----
| MR | ---> handover
----
---- ---- ---- |
|LFN2| |LFN3| |LFN5||
---- ---- ---- |MNP1 or MNP2
| | | |
-------------------+
For a HNP with prefix length 64, two or more MNPs are generated, each
having a prefix length longer than 64. For brevity and without
losing generality, we present a detailed division example for a
fictitious addressing system whose "IP" addresses are of a maximum
length of 5 bits (instead of 128 bits of IPv6).
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A0 11000/5
A2 11010/5 To be used by LFN2
A3 11011/5 To be used by LFN3
+--------> MNP1 1101/4
|
|
HNP 11000/2 +--------> A1 11001/5 To be used on egress of MR
|
|
+--------> MNP2 111/3
A4 11100/5
A5 11101/5 To be used by LFN5
A6 11110/5 To be used by LFN6
A7 11111/5
In this example, the HNP/2 11000 is assigned by LMA to MR. The MR
divides this into MNP1 1101/4 and MNP2 111/3, and an address A1
11001/5. The MNP1 and MNP2 are used to help LFNs within the moving
network to configure full /5 addresses. This may be achieved either
with DHCPv6 (MR or a DHCPv6 Server send these addresses) or with
stateless address auto-configuration (MR or a Router send Router
Advertisements containing MNP1 and/or MNP2).
In most PMIPv6 implementations for MHs, the MAG contains a routing
table entry with respect to the allocated HNP. Depending on the
nature of the link between MAG and MR, this entry has two different
forms: [HNP, vif, *] in case of point-to-point links (typically used
in cellular systems) and [HNP, eth, *] (typically used in WiFi
hotspot shared links). The vif is a virtual interface, e.g. "ppp0",
whereas eth is a real interface, e.g. "eth0".
In the case of point-to-point links, it is not necessary to add any
additional behaviour for MR to work (LFN to be reachable from CN).
It is sufficient for MR to perform HNP division as described above.
On the contrary, in the case of shared links, it is necessary to
perform an operation of Neighbor Discovery proxying on the Mobile
Router. When MAG receives a packet from CN addressed to LFN, it
would solicit the MAC address of LFN on the MAG-MR link (even though
LFN is not present on that link). For this reason, the MR must
pretend it owns the IP address of LFN and respond to that
solicitation with its own MAC address.
The HNP division mechanism requires that the MNP be part of the HNP
(e.g. MNP must have the leftmost n bits the same as the prefix
length of HNP), and its length be longer. In case of an HNP/64 and
the use of Ethernet for LFNs, only the DHCPv6 protocol can be used by
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LFNs, and not SLAAC, because stateless address auto-configuration is
not possible for MNPs whose prefix length is longer than 64, the
Interface ID being of length precisely 64 for Ethernet.
2.2. DHCPv6-PD and PMIPv6 Enhancements
A second mechanism considers the use of MNP completely different than
HNP (may differ on the leftmost bit), hence the use of SLAAC with
Ethernet LFNs and HNP/64 is possible, but whereby the PMIPv6 protocol
implementation must be modified; this mechanism involves also the use
of the DHCPv6 Prefix Delegation protocol.
For this mechanism, we consider the following PMIP topology augmented
with DHCP entities:
----
| CN |
----
|
Internet
|
----
| LMA|
----
----- |
| DSe |------ Operator Network
----- / \
/ \
---- ----
|MAG1| |MAG2|
|DRe1| |DRe2|
---- ----
| HNP
----
| MR | ---> handover
----
---- ---- ---- |
|LFN2| |LFN3| |LFN5||
---- ---- ---- |MNP1 or MNP2
| | | |
-------------------+
The DSe entity is a DHCPv6 Server. Each MAG also runs a DRe which is
a DHCPv6 Relay.
It is necessary to modify the DRe, LMA and MAG behaviour. Depending
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on deployment, it may be preferable to modify or to not modify the
DHCPv6 Server as well. In case it is not acceptable to modify the
DSe the following protocol is proposed:
LFN MR MAG DSe LMA CN
| RA defr | | | | |
|<--------| DHCPReq | | | |
| |-------->| | | |
| | | RelFwd | | |
| | |------->| | |
| | |DUID=MNID | |
| | | | | |
| | | RelRep | | |
| | |<-------| | |
| | | MNP | | |
| | | | | |
| | | PBU MNID, MNP | |
| | |--------|------>| |
| | | PBA MNID, MNP | |
| | |<-------|-------| |
| | DHCPRep | | | |
| RA MNP |<--------| | | |
|<--------| | | | |
| | | | | |
|<--------|---------|========|=======|------->| app data
| | | | | |
In case it is not acceptabe to modify the DSe the following protocol
is proposed:
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LFN MR MAG DSe LMA CN
| RA defr | | | | |
|<--------| DHCPReq | | | |
| |-------->| | | |
| | | RelFwd | | |
| | |------->| | |
| | |DUID=MNID | |
| | | | | |
| | | | D2PU | |
| | | |------>| |
| | | | MNID | |
| | | | MNP | |
| | | | | |
| | | | D2PA | |
| | | |<----- | |
| | | | MNID | |
| | | RelRep | MNP | |
| | |<-------| | |
| | | | | |
| | | PBU MNID, MNP | |
| | |--------|------>| |
| | | | | |
| | | PBA MNID, MNP | |
| | |<-------|-------| |
| | DHCPRep | | | |
| RA MNP |<--------| | | |
|<--------| | | | |
| | | | | |
|<------------------=========|========------->| app data
| | | | | |
D2PU and D2PA are new message formats, to be further defined.
The structure of the PBU message is enhanced with respect to the
original. Its structure is presented in the following figure:
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Proxy Binding Update Message (existing + Q)
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence # |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|H|L|K|M|R|P|Q| Reserved | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Mobile Node Identifier Option (existing)
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Option Type | Option Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Subtype | Identifier ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Mobile Network Prefix (MNP) Option (NEW)
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved | Prefix Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Mobile Network Prefix (MNP) +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
'R' flag in PBU: it must be reset.
'Q' flag in PBU: it must be set. It signifies this PBU is sent for
an MNP (and not for an HNP).
Type field in the MNP Option: a new type TBA.
Length field in the MNP Option: the length of the MNP as was assigned
by DHCP.
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3. Security Considerations
DHCPv6 and PMIPv6 have security options that should be used in this
contect as well.
Security risks exist in the process of MR performing proxy Neighbor
Discovery on behalf of LFN, if done without explicit authorization
provided by LFN.
Security risks exist when performing D2PU and D2PA.
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4. Acknowledgements
The mechanisms described in this draft were inspired by several
discussions on the NETEXT and intarea email lists. Contributors of
these discussions are acknowledged here.
In the process of filing for patent applications the lawyers provided
comments which led to better descriptions.
Administratively, this work has been performed in the framework of
CELTIC project CP7-011 MEVICO. The authors would like to acknowledge
the contributions of their colleagues, although the views expressed
are those of the authors and do not necessarily represent the
project.
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5. Normative References
[I-D.ietf-netext-pd-pmip]
Zhou, X., Korhonen, J., Williams, C., and S. Gundavelli,
"Prefix Delegation for Proxy Mobile IPv6",
draft-ietf-netext-pd-pmip-01 (work in progress),
October 2011.
[I-D.krishnan-intarea-pd-epc]
Krishnan, S., Garneij, F., Korhonen, J., and T.
Savolainen, "Prefix Delegation in Evolved Packet Core
networks", draft-krishnan-intarea-pd-epc-00 (work in
progress), February 2010.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
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Appendix A. ChangeLog
The changes are listed in reverse chronological order, most recent
changes appearing at the top of the list.
From nil to draft-petrescu-nextex-pmip-nemo-00.txt:
o The -00 version is mostly a placeholder containing the essence of
the mechanisms.
From draft-petrescu-netext-pmip-nemo-00 to -01:
o Updated the address of authors.
o Aspects described in the draft are now implemented.
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Authors' Addresses
Alexandru Petrescu
CEA, LIST
Communicating Systems Laboratory, Point Courrier 173
Palaiseau, F-91120
France
Phone: +33 169089223
Email: alexandru.petrescu@cea.fr
Michael Mathias Boc
CEA, LIST
Communicating Systems Laboratory, Point Courrier 173
Palaiseau, F-91120
France
Phone: +33 (0) 169083976
Email: michael.boc@cea.fr
Christophe Janneteau
CEA, LIST
Communicating Systems Laboratory, Point Courrier 173
Palaiseau, F-91120
France
Phone: +33 (0) 169089182
Email: christophe.janneteau@cea.fr
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