NETEXT WG S. Gundavelli
Internet-Draft Cisco
Intended status: Standards Track October 22, 2012
Expires: April 25, 2013
Applicability of Proxy Mobile IPv6 Protocol for WLAN Access Networks
draft-gundavelli-netext-pmipv6-wlan-applicability-04.txt
Abstract
Proxy Mobile IPv6 is a network-based mobility management protocol.
The protocol is designed for providing mobility management support to
a mobile node, without requiring its participation in any IP mobility
related signaling. The base protocol is defined in an access
technology independent manner, it identifies the general requirements
from the link-layer for supporting the protocol operation. However,
it does not provide any specific details on how it can be supported
on a specific access technology. This specification identifies the
key considerations for supporting Proxy Mobile IPv6 protocol on the
widely deployed wireless LAN access architectures, based on IEEE
802.11 standards. It explores the current dominant wireless LAN
deployment models and provides the needed interworking details.
Status of this Memo
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This Internet-Draft will expire on April 25, 2013.
Copyright Notice
Copyright (c) 2012 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions & Terminology . . . . . . . . . . . . . . . . . . 4
2.1. Conventions . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Deployment Models . . . . . . . . . . . . . . . . . . . . 5
3.2. Key Considerations . . . . . . . . . . . . . . . . . . . . 6
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
5. Security Considerations . . . . . . . . . . . . . . . . . . . 10
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7.1. Normative References . . . . . . . . . . . . . . . . . . . 12
7.2. Informative References . . . . . . . . . . . . . . . . . . 12
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 14
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1. Introduction
Proxy Mobile IPv6 is a network-based mobility management protocol
specified in [RFC5213]. The protocol can be used for providing
mobility management support to a mobile node within a localized
domain, without requiring its participation in any IP mobility
related signaling.
The core functional entities in the Proxy Mobile IPv6 domain are the
local mobility anchor (LMA) and the mobile access gateway (MAG). The
local mobility anchor is responsible for maintaining the mobile
node's reachability state and is the topological anchor point for the
mobile node's home network. The mobile access gateway is the entity
that performs the mobility management on behalf of a mobile node, and
it resides on the access link where the mobile node is anchored. The
mobile access gateway is responsible for detecting the mobile node's
movements to and from the access link and for initiating binding
registrations to the mobile node's local mobility anchor.
There are numerous protocol extensions defined to Proxy Mobile IPv6
protocol, for supporting various features. These features include
support for IPv4 transport and addressing support [RFC5844], GRE Key
negotiation support [RFC5845], Binding Revocation support [RFC5846].
Diameter support [RFC5779], RADIUS support
[I-D.draft-ietf-netext-radius-pmip6] and Proxy Mobile IPv6 MIB
[I-D.draft-ietf-netlmm-pmipv6-mib]. All of these features give the
protocol a completeness for being adopted as a network-based mobility
management protocol within a micro-mobility domains, based on WLAN
access architectures.
This specification identifies the key considerations for supporting
Proxy Mobile IPv6 protocol in micro-mobility domains, such as in
wireless LAN access architectures, based on IEEE 802.11 standards.
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2. Conventions & Terminology
2.1. Conventions
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 [RFC2119].
2.2. Terminology
All the mobility related terms used in this document are to be
interpreted as defined in the Proxy Mobile IPv6 specifications
[RFC5213], [RFC5844], [RFC5845] and [RFC5846]. Additionally, this
document uses the following abbreviations:
o WLAN (Wireless Local Area Network) - A wireless network.
o WTP (Wireless Termination Point): The entity that functions as the
termination point for the network-end of the IEEE 802.11 based air
interface from the mobile node. It is also knows as the Wireless
Access Point.
o WLC (Wireless LAN Controller): The entity that provides the
centralized forwarding, routing function for the user traffic.
All the user traffic from the mobile nodes attached to the WTP's
is typically tunneled to this centralized WLAN access controller.
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3. Overview
3.1. Deployment Models
This section identifies the most common deployment models in the
wireless LAN architectures and identifies the functional collocation
points for the Proxy Mobile IPv6 functional elements.
+--------+ _----_
| | _( )_
| WLC |----( Internet )
| (LMA) | (_ _)
| | '----'
+--------+
|
-- -- --- -- --
-- --
-- --
-- IP Network --
-- --
-- --
| -- -- --- -- -- |
| | |
+-----+ +-----+ +-----+
| AP | | AP | | AP |
|(MAG)| |(MAG)| |(MAG)|
+-----+ +-----+ +-----+
. . .
/ \ / \ / \
<------ Proxy Mobile IPv6 Domain ------>
Figure 1: Collocated MAG and WTP Functions
Figure 1, illustrates the scenario where the MAG [RFC5213] is
collocated with the access point. The access point is a layer-3
device and is also the wireless termination point (WTP). The local
mobility anchor [RFC5213] is collocated with the wireless LAN
controller.
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+--------+ _----_
| | _( )_
| WLC |----( Internet )
| (LMA) | (_ _)
| | '----'
+--------+
|
-- -- --- -- --
-- --
-- --
-- IP Network --
-- --
-- --
-- -- --- -- --
/ \
+-------------+ +-------------+
| Layer-2 | | Layer-2 |
| Aggregation | | Aggregation |
| Device | | Device |
| (MAG) | | (MAG) |
+-------------+ +-------------+
| | | |
+-----+ +-----+ +-----+ +-----+
| AP | | AP | | AP | | AP |
| (L2)| | (L2)| | (L2)| | (L2)|
+-----+ +-----+ +-----+ +-----+
. . . .
/ \ / \ / \ / \
<------ Proxy Mobile IPv6 Domain ------>
Figure 2: Collocated MAG with the layer-2 aggregation device
Figure 2, illustrates the scenario where the MAG [RFC5213] is
collocated with the layer-2 aggregation device. The access point in
this model is a layer-2 device and is also the wireless termination
point (WTP). The local mobility anchor [RFC5213] is collocated with
the wireless LAN controller.
3.2. Key Considerations
Wireless LAN architectures have evolved from single autonomous access
points to systems consisting of a centralized wireless LAN Controller
and access points. In today's deployments, the wireless LAN
controller and the access points are configured to perform certain
manageability (Ex: CAPWAP) related functions. For enabling network-
based mobility management in these architectures, based on Proxy
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Mobile IPv6, these network elements must apply the following
considerations.
o The local mobility anchor [RFC5213] function can be collocated on
any access edge device, such as an access controller. This access
controller in in some deployments can be configured to host both
the mobility management and other provisioning functions (as
specified in CAPWAP specifications, [RFC5415] and [RFC5415]). In
some deployments, these functions can be non-collocated).
o If the access point is configured to operate as an IP router
(layer-3 device), with IP forwarding enabled between the wireless
and wired links, the mobile access gateway [RFC5213] function can
be collocated on the access point.
o If the access point is configured to operate as a bridge (layer-2
device), with layer-2 bridging enabled between the wireless and
wired links, the mobile access gateway [RFC5213] function can be
collocated on the aggregation device terminating the layer-2
devices.
o The mobile access gateway when sending the Proxy Binding Update
message MUST identify the access technology type, it MUST include
the Access Technology Type [RFC5213] option, and the value in the
option MUST be set to (4) (IEEE 802.11a/b/g).
o The All the network entities in a Proxy Mobile IPv6 domain MUST be
able to identify a mobile node, using its MN-Identifier [RFC5213].
This identifier MUST be stable and unique across the Proxy Mobile
IPv6 domain. The mobility entities in the Proxy Mobile IPv6
domain MUST be able to use this identifier in the signaling
messages and unambiguously identify a given mobile node. The
mobile access MUST learn this identifier from the access
authentication mechanisms as specified in
[draft-liebsch-netext-pmip6-authiwk].
o The Proxy Mobile IPv6 protocol is designed to support a Per-MN-
Prefix [RFC5213] model. In this model, each mobile node is
assigned a set of unique IPv6 prefixes which are not shared with
any other node. The mobile access gateway ensures, the Router
Advertisement [RFC4861] messages that a mobile node receives
contains its own set of IPv6 prefixes. In access networks where
the link between the mobile node and the mobile access is a point-
to-point link, supporting this semantic does not require any
special considerations. However, on IEEE 802.11 based access
links, which is a shared link, the mobile access gateway MUST
transmit the multicast messages as unicast messages on the link-
layer. This approach is specified in
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[I-D.draft-gundavelli-v6ops-l2-unicast].
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4. IANA Considerations
This specification does not require any IANA actions.
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5. Security Considerations
All the security considerations from the base Proxy Mobile IPv6
specifications, [RFC5213] and [RFC5844], apply equally well to Proxy
Mobile IPv6 domains supporting IEEE 802.11-based access networks.
The support for IEEE 802.11-based access networks does not require
any new security considerations and does not introduce any new
security vulnerabilities known at this time.
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6. Acknowledgements
The author of this document thanks the members of the NETLMM working
group for all the discussions related to this topic.
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7. References
7.1. Normative References
[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.
[RFC5779] Korhonen, J., Bournelle, J., Chowdhury, K., Muhanna, A.,
and U. Meyer, "Diameter Proxy Mobile IPv6: Mobile Access
Gateway and Local Mobility Anchor Interaction with
Diameter Server", RFC 5779, February 2010.
[RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", RFC 5844, May 2010.
[RFC6085] Gundavelli, S., Townsley, M., Troan, O., and W. Dec,
"Address Mapping of IPv6 Multicast Packets on Ethernet",
RFC 6085, January 2011.
7.2. Informative References
[I-D.liebsch-netext-pmip6-authiwk]
Gundavelli, S., Liebsch, M., and P. Seite, "PMIPv6 inter-
working with WiFi access authentication",
draft-liebsch-netext-pmip6-authiwk-05 (work in progress),
September 2012.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007.
[RFC5415] Calhoun, P., Montemurro, M., and D. Stanley, "Control And
Provisioning of Wireless Access Points (CAPWAP) Protocol
Specification", RFC 5415, March 2009.
[RFC5845] Muhanna, A., Khalil, M., Gundavelli, S., and K. Leung,
"Generic Routing Encapsulation (GRE) Key Option for Proxy
Mobile IPv6", RFC 5845, June 2010.
[RFC5846] Muhanna, A., Khalil, M., Gundavelli, S., Chowdhury, K.,
and P. Yegani, "Binding Revocation for IPv6 Mobility",
RFC 5846, June 2010.
[RFC6224] Schmidt, T., Waehlisch, M., and S. Krishnan, "Base
Deployment for Multicast Listener Support in Proxy Mobile
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IPv6 (PMIPv6) Domains", RFC 6224, April 2011.
[RFC6475] Keeni, G., Koide, K., Gundavelli, S., and R. Wakikawa,
"Proxy Mobile IPv6 Management Information Base", RFC 6475,
May 2012.
[RFC6572] Xia, F., Sarikaya, B., Korhonen, J., Gundavelli, S., and
D. Damic, "RADIUS Support for Proxy Mobile IPv6",
RFC 6572, June 2012.
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Author's Address
Sri Gundavelli
Cisco
170 West Tasman Drive
San Jose, CA 95134
USA
Email: sgundave@cisco.com
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