Internet Engineering Task Force (IETF) G. Zorn
Request for Comments: 7156 Network Zen
Category: Standards Track Q. Wu
ISSN: 2070-1721 Huawei
J. Korhonen
Broadcom
April 2014
Diameter Support for Proxy Mobile IPv6 Localized Routing
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 between an MN's MAG and the MAG of its Correspondent Node
(CN) without involving any LMA. In a Proxy Mobile IPv6 deployment,
it may be desirable to control the establishment of localized routing
sessions between two MAGs in a Proxy Mobile IPv6 domain by requiring
that the session be authorized. This document specifies how to
accomplish this using the Diameter protocol.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/RFC 7156.
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Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Solution Overview . . . . . . . . . . . . . . . . . . . . . . 3
4. Attribute Value Pair Used in This Document . . . . . . . . . 4
4.1. User-Name AVP . . . . . . . . . . . . . . . . . . . . . . 5
4.2. PMIP6-IPv4-Home-Address AVP . . . . . . . . . . . . . . . 5
4.3. MIP6-Home-Link-Prefix AVP . . . . . . . . . . . . . . . . 5
4.4. MIP6-Feature-Vector AVP . . . . . . . . . . . . . . . . . 5
5. Example Signaling Flows for Localized Routing Service
Authorization . . . . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 10
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
10.1. Normative References . . . . . . . . . . . . . . . . . . 10
10.2. Informative References . . . . . . . . . . . . . . . . . 11
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1. Introduction
Proxy Mobile IPv6 (PMIPv6) [RFC 5213] allows the Mobile Access Gateway
(MAG) to optimize media delivery by locally routing packets from a
Mobile Node (MN) to a Correspondent Node (CN) that is locally
attached to an access link connected to the same Mobile Access
Gateway, avoiding tunneling them to the Mobile Node's Local Mobility
Anchor (LMA). This is referred to as "local routing" in RFC 5213
[RFC 5213]. However, this mechanism is not applicable to the typical
scenarios in which the MN and CN are connected to different MAGs and
are registered to the same LMA or different LMAs. [RFC 6279] takes
those typical scenarios into account and defines the problem
statement for PMIPv6 localized routing. Based on the scenarios A11,
A12, and A21 described in [RFC 6279], [RFC 6705] specifies the PMIPv6
localized routing protocol that is used to establish a localized
routing path between two Mobile Access Gateways in a PMIPv6 domain.
This document describes Authentication, Authorization, and Accounting
(AAA) support using Diameter [RFC 6733] for the authorization
procedure between the PMIPv6 mobility entities (MAG or LMA) and a AAA
server within a Proxy Mobile IPv6 domain for localized routing in the
scenarios A11, A12, and A21 described in [RFC 6279].
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].
3. Solution Overview
This document addresses how to provide authorization information to
the Mobile Node's MAG or LMA to enable localized routing and resolve
the destination MN's MAG by means of interaction between the LMA and
the AAA server. Figure 1 shows the reference architecture for
Localized Routing Service Authorization. This reference architecture
assumes that
o If the MN and CN belong to different LMAs, the MN and CN should
share the same MAG (i.e., scenario A12 described in [RFC 6279]),
e.g., MN1 and CN2 in Figure 1 are attached to MAG1 and belong to
LMA1 and LMA2, respectively. Note that LMA1 and LMA2 in Figure 1
are in the same provider domain (as described in [RFC 6279]).
o If the MN and CN are attached to different MAGs, the MN and CN
should belong to the same LMA (i.e., scenario A21 described in
[RFC 6279]); for example, MN1 and CN3 in Figure 1 are attached to
MAG1 and MAG3, respectively, but belong to LMA1.
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o The MN and CN may belong to the same LMA and may be attached to
the same MAG (i.e., scenario A11 described in [RFC 6279]), e.g.,
MN1 and CN1 in Figure 1 are both attached to the MAG1 and belong
to LMA1.
o The MAG and LMA support Diameter client functionality.
+---------+
+---------------------->| AAA & |
| +------>| Policy |
| | | Profile |
| Diameter +---------+
| |
| +--V-+ +----+
| +------->|LMA1| |LMA2|
| | +---++ +----+
| | | | |
Diameter | | +-------+---------
| | | | |
| PMIP | | \\
| | // // \\
| | // // \\
| | // // \\
| | | | |
| +---->+---------------+ +----+
| | MAG1 | |MAG3|
+-------->+---------------+ +----+
: : : :
+---+ +---+ +---+ +---+
|MN1| |CN1| |CN2| |CN3|
+---+ +---+ +---+ +---+
Figure 1: Localized Routing Service Authorization Reference
Architecture
The interaction of the MAG and LMA with the AAA server according to
the extension specified in this document is used to authorize the
localized routing service.
4. Attribute Value Pair Used in This Document
This section describes Attribute Value Pairs (AVPs) and AVP values
defined by this specification or reused from existing specifications
in a PMIPv6-specific way.
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4.1. User-Name AVP
The User-Name AVP (AVP Code 1) is defined in [RFC 6733], Section 8.14.
This AVP is used to carry the Mobile Node identifier (MN-Identifier)
[RFC 5213] in the Diameter AA-Request message [RFC 7155] sent to the
AAA server. The MN-Identifier is defined in PMIPv6 [RFC 5213].
4.2. PMIP6-IPv4-Home-Address AVP
The PMIP6-IPv4-Home-Address AVP (AVP Code 505) is defined in
[RFC 5779], Section 5.2. This AVP is used to carry the Mobile Node's
IPv4 home address (IPv4-MN-HoA) in the Diameter AA-Request message
[RFC 7155] sent to the AAA server. The IPv4-MN-HoA is defined in
[RFC 5844].
4.3. MIP6-Home-Link-Prefix AVP
The MIP6-Home-Link-Prefix AVP (AVP Code 125) is defined in [RFC 5779],
Section 5.3. This AVP is used to carry the Mobile Node's home
network prefix (MN-HNP) in the Diameter AA-Request [RFC 7155] sent to
the AAA server.
4.4. MIP6-Feature-Vector AVP
The MIP6-Feature-Vector AVP is defined in [RFC 5447] and contains a
64-bit flags field used to indicate supported capabilities to the AAA
server. This document allocates a new capability flag bit according
to the IANA rules in RFC 5447 [RFC 5447].
INTER_MAG_ROUTING_SUPPORTED (0x0002000000000000)
When set, this flag indicates support or authorization of Direct
routing of IP packets between MNs anchored to different MAGs
without involving any LMA.
During the network access authentication and authorization procedure
[RFC 5779], this flag is set by the MAG or LMA in the MIP6-Feature-
Vector AVP included in the request to indicate to the home AAA server
(HAAA) that inter-MAG direct routing may be provided to the mobile
node identified by the User-Name AVP. By setting the
INTER_MAG_ROUTING_SUPPORTED flag in the response, the HAAA indicates
to the MAG or LMA that direct routing of IP packets between this
mobile node and another node anchored to a different MAG is
authorized. The MAG and the LMA set also the
INTER_MAG_ROUTING_SUPPORTED flag of the MIP6-Feature-Vector AVP in
AA-R sent to the HAAA for requesting authorization of inter-MAG
direct routing between the mobile nodes identified in the request by
two distinct instances of the User-Name AVP. If this bit is set in
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the returned MIP6-Feature-Vector AVP, the HAAA authorizes direct
routing of packets between MNs anchored to different MAGs. When the
INTER_MAG_ROUTING_SUPPORTED flag is cleared, either in request or
response, it indicates that the procedures related to authorization
of localized routing between MNs anchored to different MAGs is not
supported or not authorized. MAG and LMA compliant to this
specification MUST support this policy feature on a per-MN and per-
subscription basis.
5. Example Signaling Flows for Localized Routing Service Authorization
Localized Routing Service Authorization can happen during the network
access authentication procedure [RFC 5779] before localized routing is
initialized. In this case, the preauthorized pairs of LMA / prefix
sets can be downloaded to Proxy Mobile IPv6 entities during the
procedure from [RFC 5779]. Localized routing can be initiated once
the destination of a received packet matches one or more of the
prefixes received during the procedure from [RFC 5779].
Figure 2 shows an example scenario in which MAG1 acts as a Diameter
client, processing the data packet from MN1 to MN2 and requesting
authorization of localized routing (i.e., MAG-Initiated LR
authorization). In this example scenario, MN1 and MN2 are attached
to the same MAG and anchored to the different LMAs (i.e., scenario
A12 described in [RFC 6279]). In this case, MAG1 knows that MN2
belongs to a different LMA (which can be determined by looking up the
binding cache entries corresponding to MN1 and MN2 and comparing the
addresses of LMA1 and LMA2). In order to set up a localized routing
path with MAG2, MAG1 acts as Diameter client and sends an AA-Request
message to the AAA server. The message contains an instance of the
MIP6-Feature-Vector (MFV) AVP [RFC 5447] with the
LOCAL_MAG_ROUTING_SUPPORTED bit ([RFC 5779], Section 5.5) set, two
instances of the User-Name AVP [RFC 6733] containing the identifiers
of MN1 and MN2. In addition, the message may contain either:
- an instance of the MIP6-Home-Link-Prefix AVP [RFC 5779] carrying the
MN1's IPv4 address;
- an instance of the PMIP6-IPv4-Home-Address AVP [RFC 5779] carrying
the MN1's home network prefix (MN-HNP).
The AAA server authorizes the localized routing service by checking
if MN1 and MN2 are allowed to use localized routing. If so, the AAA
server responds with a AAA message encapsulating an instance of the
MIP6-Feature-Vector (MFV) AVP [RFC 5447] with the
LOCAL_MAG_ROUTING_SUPPORTED bit ([RFC 5779], Section 5.5) set
indicating that direct routing of IP packets between MNs anchored to
the same MAG is authorized. MAG1 then knows that the localized
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routing between MN1 and MN2 is allowed. Then, MAG1 sends the Request
messages respectively to LMA1 and LMA2. The request message is the
Localized Routing Initialization (LRI) message in Figure 2 and
belongs to the Initial phase of the localized routing. LMA1 and LMA2
respond to MAG1 using the Localized Routing Acknowledge message (LRA
in Figure 2) in accordance with [RFC 6705].
In case of LRA_WAIT_TIME expiration [RFC 6705], MAG1 should ask for
authorization of localized routing again according to the procedure
described above before the LRI is retransmitted up to a maximum of
LRI_RETRIES.
+---+ +---+ +----+ +----+ +---+ +----+
|MN2| |MN1| |MAG1| |LMA1| |AAA| |LMA2|
+-|-+ +-+-+ +-+--+ +-+--+ +-+-+ +-+--+
| | Anchored | | |
o-----------------------------------------------o
| | Anchored | | |
| o------------------o | |
| Data[MN1->MN2] | | |
| |------->| | | |
| | | AA-Request(MFV, MN1,MN2) |
| | |--------------------> | |
| | | AA-Answer(MFV) | |
| | |<-------------------- | |
| | | LRI | | |
| | |-------->| | |
| | | | LRI | |
| | |----------------------------->|
| | | LRA | | |
| | |<--------| | |
| | | | LRA | |
| | |<-----------------------------|
Figure 2: MAG-Initiated Localized Routing Authorization in A12
Figure 3 shows the second example scenario, in which LMA1 acts as a
Diameter client, processing the data packet from MN2 to MN1 and
requesting the authorization of localized routing. In this scenario,
MN1 and MN2 are attached to a different MAG and anchored to the same
LMA (i.e., A21 described in [RFC 6279]), LMA knows that MN1 and MN2
belong to the same LMA (which can be determined by looking up the
binding cache entries corresponding to MN1 and MN2 and comparing the
addresses of the LMA corresponding to MN1 and LMA corresponding to
MN2). In contrast with the signaling flow shown in Figure 2, it is
LMA1 instead of MAG1 that initiates the setup of the localized
routing path.
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The Diameter client in LMA1 sends an AA-Request message to the AAA
server. The message contains an instance of the MIP6-Feature-Vector
(MFV) AVP [RFC 5447] with the INTER_MAG_ROUTING_SUPPORTED bit
(Section 4.5) set indicating direct routing of IP packets between MNs
anchored to different MAGs is supported and two instances of the
User-Name AVP [RFC 6733] containing identifiers of MN1 and MN2. The
AAA server authorizes the localized routing service by checking if
MN1 and MN2 are allowed to use localized routing. If so, the AAA
server responds with an AA-Answer message encapsulating an instance
of the MIP6-Feature-Vector (MFV) AVP [RFC 5447] with the
INTER_MAG_ROUTING_SUPPORTED bit (Section 4.5) set indicating that
direct routing of IP packets between MNs anchored to different MAGs
is authorized. LMA1 then knows the localized routing is allowed. In
a successful case, LMA1 responds to MAG1 in accordance with
[RFC 6705].
In the case of LRA_WAIT_TIME expiration [RFC 6705], LMA1 should ask
for authorization of localized routing again according to the
procedure described above before the LRI is retransmitted up to a
maximum of LRI_RETRIES.
+---+ +----+ +----+ +---+ +----+ +---+
|MN1| |MAG1| |LMA1| |AAA| |MAG2| |MN2|
+-+-+ +-+--+ +-+--+ +-+-+ +-+--+ +-+-+
| | | Anchored | |
| Anchored o-------------------+--------o
o--------+-------o Data[MN2->MN1] | |
| | |<----- | | |
| | |AA-Request(MFV,MN1,MN2) |
| | |--------->| | |
| | |AA-Answer(MFV) | |
| | LRI |<---------| | |
| |<------| LRI | |
| | LRA |------------------>| |
| |------>| LRA | |
| | |<------------------| |
Figure 3: LMA-Initiated Localized Routing Authorization in A21
Figure 4 shows another example scenario, in which LMA1 acts as a
Diameter client, processing the data packet from MN2 to MN1 and
requesting the authorization of localized routing. In this scenario,
MN1 and MN2 are attached to the same MAG and anchored to the same LMA
(i.e., A11 described in [RFC 6279]), the LMA knows that MN1 and MN2
belong to the same LMA (which can be determined by looking up the
binding cache entries corresponding to MN1 and MN2 and comparing the
addresses of LMA corresponding to MN1 and LMA corresponding to MN2).
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The Diameter client in LMA1 sends an AA-Request message to the AAA
server. The message contains an instance of the MIP6-Feature-Vector
AVP [RFC 5447] with the LOCAL_MAG_ROUTING_SUPPORTED bit set and two
instances of the User-Name AVP [RFC 6733] containing the identifiers
MN1 and MN2. The AAA server authorizes the localized routing service
by checking if MN1 and MN2 are allowed to use localized routing. If
so, the AAA server responds with an AA-Answer message encapsulating
an instance of the MIP6-Feature-Vector (MFV) AVP [RFC 5447] with the
LOCAL_MAG_ROUTING_SUPPORTED bit ([RFC 5779], Section 5.5) set
indicating that direct routing of IP packets between MNs anchored to
the same MAG is authorized. LMA1 then knows the localized routing is
allowed and responds to MAG1 for localized routing in accordance with
[RFC 6705].
In the case of LRA_WAIT_TIME expiration [RFC 6705], LMA1 should ask
for authorization of localized routing again according to the
procedure described above before the LRI is retransmitted up to a
maximum of LRI_RETRIES.
+---+ +---+ +----+ +----+ +---+
|MN2| |MN1| |MAG1| |LMA1| |AAA|
+-+-+ +-+-+ +-+--+ +-+--+ +-|-+
| | Anchored | |
o-----------------------o |
| | Anchored | |
| o--------+-------o Data[MN2->MN1]
| | | |<----- |
| | | |AA-Request(MFV,MN1,MN2)
| | | |--------->|
| | | |AA-Answer(MFV)
| | | LRI |<---------|
| | |<------| |
| | | LRA | |
| | |------>| |
Figure 4: LMA-Initiated Localized Routing Authorization in A11
6. Security Considerations
The security considerations for the Diameter Network Access Server
Requirements (NASREQ) [RFC 7155] and Diameter Proxy Mobile IPv6
[RFC 5779] 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.
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An authorized MAG could, in principle, track the movement of any
participating mobile nodes at the level of the MAG to which they are
anchored. If such a MAG were compromised, or under the control of a
bad actor, then such tracking could represent a privacy breach for
the set of tracked mobile nodes. In such a case, the traffic pattern
from the compromised MAG might be notable, so monitoring for, e.g.,
excessive queries from MAGs, might be worthwhile.
7. IANA Considerations
This specification defines a new value in the "Mobility Capability
Registry" [RFC 5447] for use with the MIP6-Feature-Vector AVP:
INTER_MAG_ROUTING_SUPPORTED (see Section 4.4).
8. Contributors
Paulo Loureiro, Jinwei Xia and Yungui Wang all contributed to early
versions of this document.
9. Acknowledgements
The authors would like to thank Lionel Morand, Marco Liebsch, Carlos
Jesus Bernardos Cano, Dan Romascanu, Elwyn Davies, Basavaraj Patil,
Ralph Droms, Stephen Farrel, Robert Sparks, Benoit Claise, and Abhay
Roy for their valuable comments and suggestions on this document.
10. References
10.1. Normative References
[RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC 5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
[RFC 5447] 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.
[RFC 5779] 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.
[RFC 5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", RFC 5844, May 2010.
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RFC 7156 PMIPv6 Localized Routing Support April 2014
[RFC 6705] Krishnan, S., Koodli, R., Loureiro, P., Wu, Q., and A.
Dutta, "Localized Routing for Proxy Mobile IPv6", RFC
6705, September 2012.
[RFC 6733] Fajardo, V., Arkko, J., Loughney, J., and G. Zorn,
"Diameter Base Protocol", RFC 6733, October 2012.
[RFC 7155] Zorn, G., Ed., "Diameter Network Access Server
Application", RFC 7155, April 2014.
10.2. Informative References
[RFC 6279] Liebsch, M., Jeong, S., and Q. Wu, "Proxy Mobile IPv6
(PMIPv6) Localized Routing Problem Statement", RFC 6279,
June 2011.
Authors' Addresses
Glen Zorn
Network Zen
227/358 Thanon Sanphawut
Bang Na, Bangkok 10260
Thailand
Phone: +66 (0) 87-040-4617
EMail: glenzorn@gmail.com
Qin Wu
Huawei Technologies Co., Ltd.
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Phone: +86-25-56623633
EMail: bill.wu@huawei.com
Jouni Korhonen
Broadcom
Porkkalankatu 24
FIN-00180 Helsinki
Finland
EMail: jouni.nospam@gmail.com
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