One document matched: draft-boucadair-mptcp-radius-00.txt
Network Working Group M. Boucadair
Internet-Draft C. Jacquenet
Intended status: Standards Track Orange
Expires: July 22, 2016 January 19, 2016
RADIUS Extensions for Network-Assisted Multipath TCP (MPTCP)
draft-boucadair-mptcp-radius-00
Abstract
One of the promising deployment scenarios for Multipath TCP (MPTCP)
is to enable a Customer Premises Equipment (CPE) that is connected to
multiple networks (e.g., DSL, LTE, WLAN) to optimize the usage of its
network attachments. Because of the lack of MPTCP support at the
server side, some service providers consider a network-assisted model
that relies upon the activation of a dedicated function called: MPTCP
Concentrator.
This document specifies a new Remote Authentication Dial-In User
Service (RADIUS) attribute that carries the list of IP addresses that
allow CPE devices to reach one or multiple MPTCP Concentrators.
Requirements Language
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].
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
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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 July 22, 2016.
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Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. MPTCP RADIUS Attribute . . . . . . . . . . . . . . . . . . . 4
3. Sample Use Case . . . . . . . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. Table of Attributes . . . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . 8
8.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
One of the promising deployment scenarios for Multipath TCP (MPTCP,
[RFC6824]) is to enable a Customer Premises Equipment (CPE) that is
connected to multiple networks (e.g., DSL, LTE, WLAN) to optimize the
usage of such resources, see for example [RFC4908]. This deployment
scenario relies on MPTCP proxies located on both the CPE and network
sides (Figure 1). MPTCP Proxies deployed in the network play the
role of traffic concentrator.
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IP Network #1
+------------+ _--------_ +------------+
| | (e.g., LTE ) | |
| CPE +======================+ |
| (MPTCP | (_ _) |Concentrator|
| Proxy) | (_______) | (MPTCP |
| | | Proxy) |------> Internet
| | | |
| | IP Network #2 | |
| | _--------_ | |
| | ( e.g., DSL ) | |
| +======================+ |
| | (_ _) | |
+-----+------+ (_______) +------------+
|
----CPE network----
|
end-nodes
Figure 1: "Network-Assisted" MPTCP Design
Within this document, an MPTCP Concentrator (or concentrator) refers
to a functional element that is responsible for aggregating the
traffic originated by a group of CPEs. This element is located in
the network. One or multiple concentrators can be deployed in the
network to assist MPTCP-enabled CPEs to establish MPTCP connections
via their available network attachments. On the uplink path, the
concentrator terminates the MPTCP connections [RFC6824] received from
its customer-facing interfaces and transforms these connections into
legacy TCP connections [RFC0793] towards upstream servers. On the
downlink path, the concentrator turns the legacy server's TCP
connection into MPTCP connections towards its customer-facing
interfaces.
Both implicit (where a CPE has no specific knowledge of any
concentrator deployed in the network) and explicit modes are
considered to steer traffic towards an MPTCP Concentrator. This
document focuses on the explicit mode that consists in explicitly
configuring a CPE with the reachability information of a MPTCP
concentrator.
This document specifies a new Remote Authentication Dial-In User
Service (RADIUS, [RFC2865]) attribute that carries the MPTCP
Concentrator IP address list (Section 2). A sample use case is
described in Section 3. In order to accommodate both IPv4 and IPv6
deployment contexts, the same attribute is used to convey an IPv4 or
IPv6 address. Note that one or multiple IPv4 and/or IPv6 addresses
may be returned to a requesting CPE.
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This document assumes that the MPTCP concentrator(s) reachability
information can be stored in Authentication, Authorization, and
Accounting (AAA) servers while the CPE configuration is usually
provided by means of DHCP ([RFC2131][RFC3315]).
This specification assumes an MPTCP Concentrator is reachable through
one or multiple IP addresses. As such, a list of IP addresses can be
communicated via RADIUS. Also, it assumes the various network
attachments provided to an MPTCP-enabled CPE are managed by the same
administrative entity.
2. MPTCP RADIUS Attribute
The RADIUS MPTCP-Concentrator attribute contains the IP address of an
MPTCP Concentrator that is assigned to a CPE. Because multiple MPTCP
Concentrator IP addresses may be provisioned to an authorised CPE
(that is a CPE entitled to solicit the resources of a concentrator to
establish MPTCP connections), multiple instances of the MPTCP-
Concentrator attribute MAY be included; each instance of the
attribute carries a distinct IP address.
The format of the MPTCP-Concentrator attribute is shown in Figure 2.
The fields are transmitted from left to right.
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 | ip-address ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// ... ip-address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2
The description of the fields is as follows:
o Type: TBA (see Section 6).
o Length: 6 or 18.
o ip-address: This field may include an IPv4 address (32 bits) or an
IPv6 address (128 bit) of the MPTCP concentrator.
The MPTCP-Concentrator attribute MUST NOT include multicast and host
loopback addresses [RFC6890]. Anycast addresses are allowed to be
included in an MPTCP-Concentrator attribute.
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The MPTCP-Concentrator Attribute MAY appear in a RADIUS Access-Accept
packet. It MAY also appear in a RADIUS Access-Request packet as a
hint to the RADIUS server to indicate a preference, although the
server is not required to honor such a hint.
The MPTCP-Concentrator Attribute MAY appear in a CoA-Request packet.
The MPTCP-Concentrator Attribute MAY appear in a RADIUS Accounting-
Request packet.
The MPTCP-Concentrator Attribute MUST NOT appear in any other RADIUS
packet.
3. Sample Use Case
This section does not aim to provide an exhaustive list of deployment
scenarios where the use of the RADIUS MPTCP-Concentrator attribute
can be helpful. Typical deployment scenarios are described, for
instance, in [RFC6911].
Figure 3 shows an example where a CPE is assigned an MPTCP
Concentrator. This example assumes that the Network Access Server
(NAS) embeds both RADIUS client and DHCPv6 server capabilities.
CPE NAS AAA
DHCPv6 client DHCPv6 server server
| | |
|---------DHCPv6 Solicit---------->| |
| |----Access-Request ---->|
| | |
| |<----Access-Accept------|
| | (MPTCP-Concentrator) |
|<-------DHCPv6 Advertisement------| |
| (OPTION_V6_MPTCP) | |
| | |
|---------DHCPv6 Request---------->| |
| | |
|<---------DHCPv6 Reply------------| |
| (OPTION_V6_MPTCP) | |
DHCPv6 RADIUS
Figure 3: Sample Flow Example (1)
Upon receipt of the DHCPv6 Solicit message from a CPE, the NAS sends
a RADIUS Access-Request message to the AAA server. Once the AAA
server receives the request, it replies with an Access-Accept message
(possibly after having sent a RADIUS Access-Challenge message and
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assuming the CPE is entitled to connect to the network) that carries
a list of parameters to be used for this session, and which include
MPTCP-Concentrator reachability information (namely a list of IP
addresses).
The content of the MPTCP-Concentrator attribute is then used by the
NAS to complete the DHCPv6 procedure that the CPE initiated to
retrieve information about the MPTCP Concentrator it has been
assigned.
Upon change of the MPTCP Concentrator assigned to a CPE, the RADIUS
server sends a RADIUS CoA message [RFC5176] that carries the RADIUS
MPTCP-Concentrator attribute to the NAS. Once that message is
accepted by the NAS, it replies with a RADIUS CoA ACK message. The
NAS replaces the old MPTCP Concentrator with the new one.
Figure 4 shows another example where a CPE is assigned an MPTCP
Concentrator, but the CPE uses DHCPv6 to retrieve a list of IP
addresses of an MPTCP concentrator.
CPE NAS AAA
DHCPv4 client DHCPv4 server server
| | |
|-----------DHCPDISCOVER---------->| |
| |----Access-Request ---->|
| | |
| |<----Access-Accept------|
| | (MPTCP-Concentrator) |
|<------------DHCPOFFER------------| |
| (OPTION_V4_MPTCP) | |
| | |
|------------DHCPREQUEST---------->| |
| (OPTION_V4_MPTCP) | |
| | |
|<-----------DHCPACK---------------| |
| (OPTION_V4_MPTCP) | |
DHCPv4 RADIUS
Figure 4: Sample Flow Example (2)
Some deployments may rely on the mechanisms defined in [RFC4014] or
[RFC7037], which allows a NAS to pass attributes obtained from a
RADIUS server to a DHCP server.
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4. Security Considerations
RADIUS-related security considerations are discussed in [RFC2865].
MPTCP-related security considerations are discussed in [RFC6824] and
[RFC6181].
Traffic theft is a risk if an illegitimate concentrator is inserted
in the path. Indeed, inserting an illegitimate concentrator in the
forwarding path allows to intercept traffic and can therefore provide
access to sensitive data issued by or destined to a host. To
mitigate this threat, secure means to discover a concentrator should
be enabled.
5. Table of Attributes
The following table provides a guide as what type of RADIUS packets
that may contain these attributes, and in what quantity.
Access- Access- Access- Challenge Accounting # Attribute
Request Accept Reject Request
0+ 0+ 0 0 0+ TBA MPTCP-Concentrator
CoA-Request CoA-ACK CoA-NACK # Attribute
0+ 0 0 TBA MPTCP-Concentrator
The following table defines the meaning of the above table entries:
0 This attribute MUST NOT be present in packet.
0+ Zero or more instances of this attribute MAY be present in packet.
6. IANA Considerations
IANA is requested to assign a new RADIUS attribute type from the IANA
registry "Radius Attribute Types" located at
http://www.iana.org/assignments/radius-types:
MPTCP-Concentrator (TBA)
7. Acknowledgements
To be completed.
8. References
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8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, DOI 10.17487/RFC2865, June 2000,
<http://www.rfc-editor.org/info/rfc2865>.
[RFC6890] Cotton, M., Vegoda, L., Bonica, R., Ed., and B. Haberman,
"Special-Purpose IP Address Registries", BCP 153,
RFC 6890, DOI 10.17487/RFC6890, April 2013,
<http://www.rfc-editor.org/info/rfc6890>.
8.2. Informative References
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7,
RFC 793, DOI 10.17487/RFC0793, September 1981,
<http://www.rfc-editor.org/info/rfc793>.
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol",
RFC 2131, DOI 10.17487/RFC2131, March 1997,
<http://www.rfc-editor.org/info/rfc2131>.
[RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
C., and M. Carney, "Dynamic Host Configuration Protocol
for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July
2003, <http://www.rfc-editor.org/info/rfc3315>.
[RFC4014] Droms, R. and J. Schnizlein, "Remote Authentication Dial-
In User Service (RADIUS) Attributes Suboption for the
Dynamic Host Configuration Protocol (DHCP) Relay Agent
Information Option", RFC 4014, DOI 10.17487/RFC4014,
February 2005, <http://www.rfc-editor.org/info/rfc4014>.
[RFC4908] Nagami, K., Uda, S., Ogashiwa, N., Esaki, H., Wakikawa,
R., and H. Ohnishi, "Multi-homing for small scale fixed
network Using Mobile IP and NEMO", RFC 4908,
DOI 10.17487/RFC4908, June 2007,
<http://www.rfc-editor.org/info/rfc4908>.
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[RFC5176] Chiba, M., Dommety, G., Eklund, M., Mitton, D., and B.
Aboba, "Dynamic Authorization Extensions to Remote
Authentication Dial In User Service (RADIUS)", RFC 5176,
DOI 10.17487/RFC5176, January 2008,
<http://www.rfc-editor.org/info/rfc5176>.
[RFC6181] Bagnulo, M., "Threat Analysis for TCP Extensions for
Multipath Operation with Multiple Addresses", RFC 6181,
DOI 10.17487/RFC6181, March 2011,
<http://www.rfc-editor.org/info/rfc6181>.
[RFC6824] Ford, A., Raiciu, C., Handley, M., and O. Bonaventure,
"TCP Extensions for Multipath Operation with Multiple
Addresses", RFC 6824, DOI 10.17487/RFC6824, January 2013,
<http://www.rfc-editor.org/info/rfc6824>.
[RFC6911] Dec, W., Ed., Sarikaya, B., Zorn, G., Ed., Miles, D., and
B. Lourdelet, "RADIUS Attributes for IPv6 Access
Networks", RFC 6911, DOI 10.17487/RFC6911, April 2013,
<http://www.rfc-editor.org/info/rfc6911>.
[RFC7037] Yeh, L. and M. Boucadair, "RADIUS Option for the DHCPv6
Relay Agent", RFC 7037, DOI 10.17487/RFC7037, October
2013, <http://www.rfc-editor.org/info/rfc7037>.
Authors' Addresses
Mohamed Boucadair
Orange
Rennes 35000
France
Email: mohamed.boucadair@orange.com
Christian Jacquenet
Orange
Rennes
France
Email: christian.jacquenet@orange.com
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