Network Working Group G. Zorn, Ed.
Internet-Draft Network Zen
Intended status: Standards Track Q. Wu, Ed.
Expires: August 8, 2010 Huawei
M. Liebsch
NEC
J. Korhonen
NSN
February 4, 2010
Diameter Support for Proxy Mobile IPv6 Localized Routing
draft-ietf-dime-pmip6-lr-00
Abstract
In Proxy Mobile IPv6, packets received from a Mobile Node (MN) by the
Mobile Access Gateway (MAG) to which it is attached are typically
tunneled to a Local Mobility Anchor (LMA) for routing. The term
"localized routing" refers to a method by which packets are routed
directly by the MAG without involving the LMA. In order to establish
a localized routing session between two Mobile Access Gateways in a
Proxy Mobile IPv6 domain, two tasks must be accomplished:
1. The usage of local routing must be authorized for both MAGs and
2. The address of the MAG to which the Correspondent Node (CN) is
attached must be ascertained
This document specifies how to accomplish these tasks using the
Diameter protocol.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
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The list of current Internet-Drafts can be accessed at
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http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on August 8, 2010.
Copyright Notice
Copyright (c) 2010 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Solution Overview . . . . . . . . . . . . . . . . . . . . . . 5
4. Localized Routing Service Authorization . . . . . . . . . . . 6
5. Diameter Server Authorizes MAG Location Query . . . . . . . . 8
6. Local Routing Service Authorization in Networks with
Multiple AAA Servers . . . . . . . . . . . . . . . . . . . . . 10
7. Security Considerations . . . . . . . . . . . . . . . . . . . 11
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 11
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
10.1. Normative References . . . . . . . . . . . . . . . . . . 11
10.2. Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12
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1. Introduction
Proxy Mobile IPv6 (PMIPv6) [RFC5213] allows the Mobility Access
Gateway to optimize media delivery by locally routing packets within
itself, avoiding tunneling them to the Mobile Node's Local Mobility
Anchor. This is referred to as "local routing" in RFC 5213.
However, this mechanism is not applicable to the typical scenario in
which the MN and CN are connected to different MAGs and are
registered to different LMAs. In this scenario (as described in
[I-D.ietf-netext-pmip6-lr-ps]), the relevant information needed to
set up a localized routing path (e.g., the addresses of the Mobile
Access Gateways to which the MN and CN are respectively attached) is
distributed between their respective Local Mobility Anchors. This
may complicate the setup and maintenance of localized routing.
Therefore, in order to establish a localized routing path between the
two Mobile Access Gateways, the Mobile Node's MAG must identify the
LMA that is managing the Correspondent Node's traffic and then obtain
the address of the Correspondent Node's MAG from that LMA. In Proxy
Mobile IPv6, the LMA to be assigned to the CN may be maintained as a
configured entry in the Correspondent Node's policy profile located
on an Authentication, Authorization and Accounting (AAA) server.
However, there is no relevant work discussing how AAA-based
mechanisms can be used by the Mobile Node's MAG to discover the
address of the Correspondent Node's LMA during the setup of localized
routing, The method by which the Mobile Node's MAG interacts with the
Correspondent Node's LMA to identify the Correspondent Node's MAG is
also unspecified.
This document describes AAA support for the authorization and
discovery of PMIPv6 mobility entities during localized routing. In
LMA discovery, Diameter [RFC3588] is used to authorize the localized
routing service and provide the Mobile Node's MAG/LMA with
information regarding the Correspondent Node's LMA. In MAG
discovery, AAA is used to determine whether Mobile Node's MAG is
allowed to fetch the address of the Correspondent Node's MAG from the
Correspondent Node's LMA. If MAG discovery is successful, the
Correspondent Node's LMA will respond to the Mobile Node's MAG with
the address of the Correspondent Node's MAG.
2. 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 [RFC2119].
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3. Solution Overview
MAG/LMA resolution is a prerequisite to the establishment of a direct
routing path between MAG1 and MAG2 (associated with MN1 and MN2
respectively). This document addresses how to resolve the
destination MN's MAG by means of interaction between the LMA and the
AAA server. Figure 1 shows the reference architecture for Local
Routing Service Authorization. This reference architecture assumes
o MN1 and MN2 belong to different LMAs
o the MAG and LMA support Diameter client functionality
+---------+
LMA2? | AAA & |
+------>| Policy |<----------+
| | Profile | |
Diameter +---------+ Diameter
AAA(a) AAA(b)
LMA2? +--+-+ +----+ |
+------->|LMA1| +----->|LMA2|<-------+
| +----+ | +----+
| | | |
| // | \\
PMIP // PMIP \\
| // | \\
| | | |
| +----+ MAG2? | +----+
+---->|MAG1|<--------+ |MAG2|
+----+ +----+
: :
+---+ +---+
|MN1| |MN2|
+---+ +---+
Figure 1: Local Routing Service Authorization Reference Architecture
The interaction of the MAG and LMA with the AAA server is a two step
procedure involving
a. The LMA1 interaction with the AAA server is used to authorize the
localized routing service and fetch the IP address of LMA2 from
the AAA server (step 'a' in (Figure 1))
b. LMA2 interaction with the AAA server is used to determine whether
MAG1 is allowed to obtain the IP address of MAG2 (step 'b' in
(Figure 1))
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4. Localized Routing Service Authorization
Figure 2 shows a scenario where MAG1 acts as a Diameter client,
processing the data packet from MN1 to MN2 and requesting
authorization of localized routing. In this scenario, MN1 and MN2
are anchored to LMA1 and LMA2 respectively. In order to setup a
localized routing path with MAG2, MAG1 must first locate the entity
that maintains the data required to setup the path (i.e., LMA2) by
sending a Local Routing Optimization Request message
([I-D.wu-netext-local-ro]) to LMA1. Note that the discovery of LMA2
is only done once; upon LMA1 know LMA2 address from AAA serer, LMA1
may associate LMA2 address with MN's data for future use (e.g.,
handover case). The Diameter client in LMA1 sends an AA-Request
(AAR) message to the Diameter server. The message contains an
instance of the MIP6-Feature-Vector (MFV) AVP ([RFC5447], Section
4.2.5) with the INTER_MAG_ROUTING_SUPPORTED bit Section 8 set and an
instance of the MIP6-Home-Link-Prefix AVP ([RFC5447], Section 4.2.4)
containing the IP address of MN2.
The Diameter server checks if localized routing is allowed between
MAG1 and MAG2 and if so, responds with an AA-Answer (AAA) message
encapsulating an instance of the MIP6-Agent-Info AVP
[I-D.ietf-dime-pmip6] containing the IP address and/or Fully
Qualified Domain Name (FQDN) of LMA2. LMA1 then determines the IP
address of LMA2 using the data returned in the MIP6-Agent-Info and
responds to MAG1 with the address of LMA2. MAG1 then requests the
address of MAG2 from LMA2 and uses that address to setup the
localized routing path between itself and MAG2 via a Proxy Binding
Update (PBU)/Proxy Binding Acknowledgement (PBA) message exchange
[RFC5213].
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+---+ +----+ +----+ +---+ +----+ +----+ +---+
|MN1| |MAG1| |LMA1| |AAA| |LMA2| |MAG2| |MN2|
+-+-+ +-+--+ +-+--+ +-+-+ +-+--+ +-+--+ +-+-+
| | | | | | |
| Anchored | | | Anchored |
o------------------o | o-------+--------o
Data[MN1->MN2] | | | | |
|------->| | | | | |
| |LROREQ(MN2) | | | |
| |-------->| | | | |
| | |AAR(MN2,MFV) | | |
| | |--------->| | | |
| | |AAA(LMA2) | | | |
| | |<---------| | | |
| |LRORSP(LMA2) | | | |
| |<--------| | | | |
| | PBU(LR[MN1,MN2]) | | |
| |---------+----------+------->| | |
| | PBA(LR[MAG2]) | | |
| |<--------+----------+--------| | |
| | MAGs PBU/PBA exchange| | |
| |<--------+----------+--------------->| |
| | | Data[MN1->MN2] | | |
| |=========|==========|==============->|------->|
| | | Data[MN2->MN1] | | |
|<-------|<========|==========|================|<-------|
| | | | | | |
Figure 2: MAG-initiated Localized Routing Authorization
Figure 3 shows another scenario, in which the LMA1 acts as a Diameter
client, processing the data packet from MN1 to MN2 and requesting the
authorization of localized routing. In this scenario, MN1 and MN2
are anchored to LMA1 and LMA2 respectively. In contrast with the
signaling flow of Figure 2, the difference is that it is LMA1 instead
of MAG1 which initiates the setup of the localized routing path.
The Diameter client in LMA1 sends an AA-Request (AAR) message to the
Diameter server. The message contains an instance of the MIP6-
Feature-Vector AVP ([RFC5447], Section 4.2.5) with the
INTER_MAG_ROUTING_SUPPORTED bit set and an instance of the MIP6-Home-
Link-Prefix AVP ([RFC5447], Section 4.2.4) containing the IP address
of MN2. The Diameter server checks if localized routing is allowed
between MAG1 and MAG2 and if so, responds with an AA-Answer (AAA)
message encapsulating an instance of the MIP6-Agent-Info AVP
[I-D.ietf-dime-pmip6] containing the IP address and/or Fully
Qualified Domain Name (FQDN) of LMA2. LMA1 then determines the IP
address of LMA2 using the data returned in the MIP6-Agent-Info AVP
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and forwards it to MAG1 in the Local Routing Optimization message
([I-D.wu-netext-local-ro]).
+---+ +----+ +----+ +---+ +----+ +----+ +---+
|MN1| |MAG1| |LMA1| |AAA| |LMA2| |MAG2| |MN2|
+-+-+ +-+--+ +-+--+ +-+-+ +-+--+ +-+--+ +-+-+
| | | | | | |
| Anchored | | | Anchored |
o--------+-------o | o-------+--------o
| Data[MN2->MN1] | | | | |
|--------+------>| | | | |
| | |AAR(MN2,MFV) | | |
| | |--------->| | | |
| | |AAA(LMA2) | | | |
| | |<---------| | | |
| LROREQ(MN2,LMA2) | | | |
| |<------| | | | |
| LRORSP(Succ) | | | |
| |------>| | | | |
| | | PBU(LR[MN1,MN2]) | | |
| |---------------------------->| | |
| | | PBA(LR[MAG2]) | | |
| |<----------------------------| | |
| | | MAGs PBU/PBA exch | | |
| |<----------------------------------->| |
|Data[MN1->MN2] | |
|------->|====================================>|------->|
| | | | | | |
| | | | | Data[MN2->MN1]|
|<-------|<====================================|<-------|
| | | | | | |
Figure 3: LMA-initiated Localized Routing Authorization
5. Diameter Server Authorizes MAG Location Query
Figure 4 shows a scenario in which LMA2 acts as a Diameter client,
receiving location request and requesting authorization for MAG
location lookup. In this scenario, MN1 and MN2 are anchored to LMA1
and LMA2 respectively. Upon receiving an upstream data packet, MAG1
needs to determine the recipient of localized routing, i.e., LMA2.
And then MAG1 solicits LMA2 to look up the IP address of the MAG to
which MN2 is currently attached (in this case, MAG2) by sending a
Local Routing Optimization Request message containing the IP
addresses/HNPs of MN1 and MN2. LMA2 validates the request from MAG1
by sending an AAR to the AAA server containing the IP address/HNP of
MN1 (encapsulated in an instance of the MIP6-Home-Link-Prefix AVP)
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and an instance of the MIP6-Feature-Vector AVP ([RFC5447], Section
4.2.5) with the INTER_MAG_ROUTING_SUPPORTED bit set. If the
authorization is successful, LMA2 then looks up the IP address of
MAG2 based on the IP address/HNP of MN2 and responds to MAG1 with the
IP address of MAG2.
+---+ +----+ +----+ +---+ +----+ +----+ +---+
|MN1| |MAG1| |LMA1| |AAA| |LMA2| |MAG2| |MN2|
+-+-+ +-+--+ +-+--+ +-+-+ +-+--+ +-+--+ +-+-+
| | | | | | |
| Anchored | | | Anchored |
o----------------o | o-------+--------o
Data[MN1->MN2] | | | | |
|------->| | | | | |
|+--------------+| | | | |
||Recipient=LMA2|| | | | |
|+--------------+| | | | |
| | PBU(LR[MN1,MN2]) | | |
| |-------+----------+--------->| | |
| | | |AAR(Service Type,MN1) |
| | | |<---------| | |
| | | | AAA | | |
| | | |--------->| | |
| | |PBA(LR[MAG2]) | | |
| |<----------------------------| | |
| | MAGs PBU/PBA exchange | | |
| |<----------------------------------->| |
| | | |
| |====================================>| |
| | | | | |------->|
| | | | | |Data[MN2->MN1]
|<-------|<====================================|<-------|
| | | | | | |
Figure 4: Diameter Server Authorizes MAG Location Query
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6. Local Routing Service Authorization in Networks with Multiple AAA
Servers
+------------------------------------+
( AAA )
( +--------+ Backend )
( |Redirect| )
( | Agent | )
( +--------+ )
( ^ )
( | )
( | )
( v )
( +---------+ +---------+ )
+---->| AAA1 & | | AAA2 & |<---+
| ( | Policy |<-------->| Policy | ) |
| ( | Profile | | Profile | ) |
| ( +---------+ +---------+ ) |
| ( ^ ^ ) |
| +----- | ------------------- |-------+ |
| A1 A2 |
| | | |
| | | |
Diameter v v Diameter
B1 +----+ LMA2 ? +----+ B2
| |LMA1| ------> |LMA2| |
| +----+ +----+ |
| | | |
| // \\ |
| // \\ |
| // \\ |
| | | |
| +----+ +----+ |
+---->|MAG1| |MAG2|<----+
+----+ +----+
: :
+---+ +---+
|MN1| |MN2|
+---+ +---+
Figure 5: Use of a Diameter Redirect Agent to Support Local Routing
Service Authorization in Networks with Multiple AAA servers
Referring to an architecture with multiple AAA servers (as
illustrated in Figure 5), AAA1 may not maintain the LMA to be
assigned to MN2 as a configured entry in the Correspondent Node's
Policy profile, as AAA2 holds this information in its policy store.
In such a case, AAA1 contacts a Diameter redirect agent [RFC3588] to
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request the AAA server being responsible for maintaining MN2's policy
profile. AAA2 checks if localized routing is allowed between MAG1
and MAG2 and if so, responds with the IP address of LMA2
corresponding to MN2 and sends the results back to LMA1 via AAA1.
Details about the use of redirect agents in this context are beyond
scope of this document.
7. Security Considerations
The security considerations for the Diameter NASREQ [RFC4005] and
Diameter Proxy Mobile IPv6 [I-D.ietf-dime-pmip6] applications are
also applicable to this document.
The service authorization solicited by the MAG or the LMA relies upon
the existing trust relationship between the MAG/LMA and the AAA
server.
8. IANA Considerations
This specification specifies a new value in the Mobility Capability
registry [RFC5447] for use with the MIP6-Feature-Vector AVP:
INTER_MAG_ROUTING_SUPPORTED (0x0000080000000000).
9. Contributors
Paulo Loureiro, Jinwei Xia and Yungui Wang all contributed to early
versions of this document.
10. References
10.1. Normative References
[I-D.ietf-dime-pmip6]
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", draft-ietf-dime-pmip6-04 (work in
progress), September 2009.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J.
Arkko, "Diameter Base Protocol", RFC 3588, September 2003.
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[RFC4005] Calhoun, P., Zorn, G., Spence, D., and D. Mitton,
"Diameter Network Access Server Application", RFC 4005,
August 2005.
[RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
[RFC5447] Korhonen, J., Bournelle, J., Tschofenig, H., Perkins, C.,
and K. Chowdhury, "Diameter Mobile IPv6: Support for
Network Access Server to Diameter Server Interaction",
RFC 5447, February 2009.
10.2. Informative References
[I-D.ietf-netext-pmip6-lr-ps]
Liebsch, M., Jeong, S., and W. Wu, "PMIPv6 Localized
Routing Problem Statement",
draft-ietf-netext-pmip6-lr-ps-02 (work in progress),
January 2010.
[I-D.wu-netext-local-ro]
Wu, W. and B. Sarikaya, "Proxy MIP extension for local
routing optimization", draft-wu-netext-local-ro-04 (work
in progress), October 2009.
Authors' Addresses
Glen Zorn (editor)
Network Zen
1463 East Republican Street
#358
Seattle, Washington 98112
USA
Email: gwz@net-zen.net
Qin Wu (editor)
Huawei Technologies Co., Ltd.
Site B, Floor 12F, Huihong Mansion, No.91 Baixia Rd.
Nanjing, JiangSu 210001
China
Phone: +86-25-84565892
Email: Sunseawq@huawei.com
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Marco Liebsch
NEC Europe Ltd.
NEC Europe Ltd.
Kurfuersten-Anlage 36
Heidelberg, 69115
Germany
Email: liebsch@nw.neclab.eu
Jouni Korhonen
Nokia Siemens Networks
Linnoitustie 6
Espoo FI-02600,
Finland
Email: jouni.nospam@gmail.com
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