netext X. Zhou
Internet-Draft ZTE Corporation
Intended status: Standards Track J. Korhonen
Expires: January 12, 2012 Nokia Siemens Networks
C. Williams
Consultant
July 11, 2011
Prefix Delegation for Proxy Mobile IPv6
draft-zhou-netext-pd-pmip-01.txt
Abstract
This document explains how network mobility and DHCPv6-based Prefix
Delegation works with Proxy Mobile IPv6.
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, 2012.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
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. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Zhou, et al. Expires January 12, 2012 [Page 1]
Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Convention & Terminology . . . . . . . . . . . . . . . . . . . 4
3. DHCPv6 Prefix Delegation for PMIPv6 . . . . . . . . . . . . . 5
3.1. Assumption . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. Network Mobility Service . . . . . . . . . . . . . . . . . 5
3.3. Binding association with the delegated prefix . . . . . . 6
3.3.1. Mobile Router initiated prefix delegation in PMIPv6 . 6
3.3.2. Mobile Router refresh prefix delegation in PMIPv6 . . 7
3.4. Mobile Access Gateway Operation . . . . . . . . . . . . . 7
3.4.1. Extension to Binding Update List Entry Data
Structure . . . . . . . . . . . . . . . . . . . . . . 7
3.4.2. Forwarding . . . . . . . . . . . . . . . . . . . . . . 8
3.4.3. Handover . . . . . . . . . . . . . . . . . . . . . . . 8
3.5. Local Mobility Anchor Operation . . . . . . . . . . . . . 9
3.5.1. Extension to Binding Cache Entry Data Structure . . . 9
3.5.2. Forwarding . . . . . . . . . . . . . . . . . . . . . . 9
4. Security Considerations . . . . . . . . . . . . . . . . . . . 10
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
6. Normative References . . . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13
Zhou, et al. Expires January 12, 2012 [Page 2]
Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011
1. Introduction
DHCPv6 prefix delegation [RFC 3633] (DHCPv6PD) can be used to assign
mobile network prefix(es) to a Mobile Router as specified in DHCPv6
Prefix Delegation for NEMO [draft-ietf-mext-nemo-pd-07]. However,
there is a gap currently for this NEMO support in PMIPv6
architecture. If a mobile router (MR) is provided Proxy Mobile IPv6
Protocol as its mobility management when connecting the network and
use DHCPv6PD to obtain prefix(es) for the nodes in the mobile network
behind the MR, currently neither the Mobile Access Gateway (MAG) nor
the Local Mobility Anchor (LMA) can be able to identify the packet
including delegated prefix(es). When the MR (Requesting Router) uses
DHCPv6 PD to obtain the delegated prefix(es), these prefix(es) SHOULD
be associated with the PMIPv6 binding. Otherwise the packets
addressed to the delegated prefix will be discarded by the MAG or the
LMA. This document describes extension to PMIPv6 for supporting
prefix delegation.
Zhou, et al. Expires January 12, 2012 [Page 3]
Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011
2. Convention & Terminology
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 [RFC 2119].
All the mobility related terms used in this document are to be
interpreted as defined in Mobile IPv6 [RFC 3775], Network Mobility
Basic Support protocol [RFC 3963], Proxy Mobile IPv6 specification
[RFC 5213], DHCPv6 Prefix Delegation for NEMO
[draft-ietf-mext-nemo-pd-07], DHCP Prefix Delegation [RFC3633] and
Mobility Related Terminology [RFC 3753]. This document does not
define any new terms.
Zhou, et al. Expires January 12, 2012 [Page 4]
Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011
3. DHCPv6 Prefix Delegation for PMIPv6
3.1. Assumption
This specification extends PMIPv6 to assign not only the home network
prefix but also the mobile network prefix for supporting network
mobility. It assumes that a MR is a regular IPv6 router without
extension for mobility managements. The MR sends the packets from
its mobile network to the MAG and the MAG delivers the packets to the
mobile network via the MR.
In order to use DHCPv6PD as mobile network prefix assignment
mechanism in mobile networks, this specification has following
assumptions.
o The Mobile Router MUST play the role of the Requesting Router.
o The Delegating Router can be located either at LMA or some other
device in the PMIPv6 domain.
o The MAG MUST play the role of DHCPv6 Relay Agent to intercept the
related DHCPv6 message from the Mobile Router.
o The Mobile Router (Requesting Router) MUST obtain the home network
prefix before initiating the DHCPv6 prefix delegation procedure.
o All the mobile network prefixes managed in the Delegating Router
MUST be reachable via local mobility anchor.
o The Mobile Router (Requesting Router) SHOULD support Prefix
Exclude Option for DHCPv6-based Prefix Delegation as described in
[draft-ietf-dhc-pd-exclude].
3.2. Network Mobility Service
The network mobility service of a mobile router is managed by the
mobile node's policy profile defined in [RFC 5213]. During mobile
router initial attachment procedure, the mobile access gateway MUST
identify the mobile router and acquire the mobile router!_s policy
profile to determine whether the network mobility service is offered
to the mobile router. If the network mobility service needs to be
offered to the mobile node, the mobile access gateway MUST set the
Mobile Router Flag (R) when sending the Proxy Binding Update message
to the local mobility anchor.
Zhou, et al. Expires January 12, 2012 [Page 5]
Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011
3.3. Binding association with the delegated prefix
3.3.1. Mobile Router initiated prefix delegation in PMIPv6
+-------------------+ +------------------+ +--------+ +------------+
| Mobile Router | | MAG | | LMA | | Delegating |
|(Requesting Router)| |(DHCP Relay Agent)| +--------+ | Router |
+-------------------+ +------------------+ | +------------+
| | | |
| |---------------------| |
| | 1.PMIPv6 tunnel | |
| |---------------------| |
|--2.DHCPv6 SOLICIT-->| | |
| | | |
| |--------3.PBU------->| |
| | | |
| |<-------4.PBA--------| |
| | | |
| |---------5.DHCPv6 SOLICIT---------->|
| |<--------6.DHCPv6 ADVERTISE---------|
| | | |
|<-7.DHCPv6 ADVERTISE-| | |
| | | |
|--8.DHCPv6 REQUEST-->| | |
| |--9.DHCPv6 REQUEST----------------->|
| | | |
| |<-----10.DHCPv6 REPLAY--------------|
|<--11.DHCPv6 REPLY---| | |
| | | |
Figure 1: Prefix Delegation in PMIPv6
The steps of the procedure in Figure 1 are as following.
1. The PMIPv6 tunnel is set up between the MAG and LMA. The MAG
plays function of DHCPv6 relay agent between the MN and the DHCPv6
server and intercept all the DHCP related messages.
2. The mobile router which acts as a "Requesting Router" as
described in [RFC 3633] sends DHCPv6 SOLICIT massage including one or
more IA_PD option(s) to the MAG to acquire the delegated prefix(es).
3. Upon receiving DHCPv6 SOLICIT the MAG sends a Proxy Binding
Update message including a Mobile Network Prefix mobility option as
defined in Section 4.3 of [RFC 3963] to the LMA. All the
considerations from Section 5.3.1 of [RFC 5213] MUST be applied on
the encapsulated Proxy Binding Update message.
Zhou, et al. Expires January 12, 2012 [Page 6]
Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011
4. On reception of the Proxy Binding Update the LMA returns the
assigned prefix in the Mobile Network Prefix option carried by a
Proxy Binding Acknowledgment to the MAG. The assigned prefix is the
same one which will be assigned via DHCPv6PD in step 6 which MUST be
added the delegated prefix(es) in its binding cache which is extended
as in Section 3.5.1.
5. The DHCPv6 relay agent on the MAG as described in [RFC 3315]
relays the DHCPv6 SOLICIT message to the delegation router. NOTE:
Step 3 and Step 5 are processed in parallel.
6. The delegating router inserts one or more IA_PD option(s)
including the delegated prefix(es) and send it to the MAG (DHCPv6
relay agent) via the DHCPv6 ADVERTISE message.
7. The MAG relays the DHCPv6 ADVERTISE message to the MN.
8. The MN sends DHCPv6 REQUEST message with the IA_PD option(s)
received from previous message to the MAG (DHCPv6 relay agent).
9. The MAG relays the DHCPv6 REQUEST message to the delegating
router.
10. The delegating router responses the REQUEST to the MAG via
DHCPv6 REPLY message.
11. The MN receives one or more IA_PD prefix(es) in the DHCPv6 REPLY
message from the MAG.
3.3.2. Mobile Router refresh prefix delegation in PMIPv6
When the mobile router sends DHCPv6 Renew messages to extend the
lifetime of the delegated prefix, the messages are also intercepted
by the MAG and relayed to the delegating router. If the MAG finds
that the lifetime of the delegated prefix which is stored in the
IA_PD Prefix Option carried by the DHCPv6 reply message set to zero,
the MAG SHOULD triggers a Proxy Binding Update to remove the binding
for that mobile network prefix.
3.4. Mobile Access Gateway Operation
3.4.1. Extension to Binding Update List Entry Data Structure
In order to support this specification, the conceptual Binding Cache
entry data structure needs to be extended with a new prefix
information field as [RFC 3963] does. This prefix information field
is used to store the mobile network prefix information which is
assigned to the mobile router in the Proxy Binding Acknowledgement
Zhou, et al. Expires January 12, 2012 [Page 7]
Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011
during the procedure of Binding association with the delegated prefix
in section 3.2.
3.4.2. Forwarding
Forwarding packets sent to the mobile router!_s mobile network prefix
o On receiving a packet from the bi-directional tunnel established
with the mobile router!_s local mobility anchor, the mobile access
gateway MUST use the destination address of the inner packet to
forward it on the interface where the destination mobile network
prefix is hosted.
Forwarding packets sent by the mobile router
o On receiving a packet from a mobile router connected to its access
link, the mobile access gateway MUST ensure that there is an
established binding for that mobile router with its local mobility
anchor before tunneling the packet to the mobile router!_s local
mobility anchor.
All other considerations from 6.10.5 MUST be applied here also.
3.4.3. Handover
When the mobile router moves from the previously attached mobile
access gateway to the newly attached mobile access gateway, the newly
attached mobile access gateway MAY know the mobile network prefix
which is assigned during the previous attachment from some network
element, e.g. from the previous mobile access gateway. It is out of
scope of this specification that how the newly attached mobile access
gateway obtains the previously assigned mobile network prefix. After
handover to the new mobile access gateway, a Proxy Binding Update
message including the assigned mobile network prefix (if available)
MUST be sent from the new mobile access gateway to the local mobility
anchor. The local mobility anchor MUST check the mobile network
prefix in the Proxy Binding Update message and return the same
assigned mobile network prefix in the Proxy Binding Acknowledgement
message. If the previously assigned mobile network prefix is not
available in the new mobile access gateway, the new mobile access
gateway MUST contain the mobile network prefix set with 0 in the
Proxy Binding Update message. In this case, the local mobility
anchor MUST return the same previously assigned mobile network prefix
in Proxy Binding Acknowledgement.
Zhou, et al. Expires January 12, 2012 [Page 8]
Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011
3.5. Local Mobility Anchor Operation
3.5.1. Extension to Binding Cache Entry Data Structure
In order to support this specification, the conceptual Binding Cache
entry data structure needs to be extended with a new prefix
information field as [RFC 3963] does. This prefix information field
is used to store the mobile network prefix information which is
assigned to the mobile router in the Proxy Binding Acknowledgement
during the procedure of Binding association with the delegated prefix
in section 3.2.
3.5.2. Forwarding
Intercepting packets sent to the mobile router!_s mobile network
prefix
o When the local mobility anchor is serving to the mobile router, it
MUST be able to receive packets those are sent to the mobile
router!_s mobile network. In order to receive those packets, the
mobile access gateway MUST advertise a connected route into the
Routing Infrastructure for the mobile router!_s mobile network
prefix(es).
Forwarding packets to the mobile router
o On receiving a packet from a correspondent node with the
destination address matching the mobile router!_s mobile network
prefix(es) the local mobility anchor MUST forward the packet
through the bi-directional tunnel set up for that mobile router.
All other considerations from 5.6.2 MUST be applied here also.
Zhou, et al. Expires January 12, 2012 [Page 9]
Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011
4. Security Considerations
All security considerations from the base Proxy Mobile IPv6 [RFC
5213], DHCPv6 Prefix Delegation specification [RFC 3633] apply when
using the extensions defined in this document.
Zhou, et al. Expires January 12, 2012 [Page 10]
Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011
5. IANA Considerations
This document reuses the mobile network prefix option defined in [RFC
3963] in Proxy Mobile IPv6 to assign the mobile network prefix via
DHCPv6 for prefix delegation. It does not introduce any additional
IANA considerations.
Zhou, et al. Expires January 12, 2012 [Page 11]
Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011
6. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633,
December 2003.
[RFC3963] Devarapalli, V., Wakikawa, R., Petrescu, A., and P.
Thubert, "Network Mobility (NEMO) Basic Support Protocol",
RFC 3963, January 2005.
[RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
Zhou, et al. Expires January 12, 2012 [Page 12]
Internet-Draft Prefix Delegation for Proxy Mobile IPv6 July 2011
Authors' Addresses
Xingyue Zhou
ZTE Corporation
No.50 Software Avenue, Yuhuatai District
Nanjing
China
Phone: +86-25-8801-4634
Email: zhou.xingyue@zte.com.cn
Jouni Korhonen
Nokia Siemens Networks
Linnoitustie 6
Espoo FIN-02600
Finland
Email: jouni.nospam@gmail.com
Carl Williams
Consultant
San Jose, CA
USA
Email: carlw@mcsr-labs.org
Zhou, et al. Expires January 12, 2012 [Page 13]