DMM WG P. Seite
Internet-Draft Orange
Intended status: Standards Track A. Yegin
Expires: June 18, 2016 Samsung
S. Gundavelli
Cisco
December 16, 2015
MAG Multipath Binding Option
draft-ietf-dmm-mag-multihoming-00.txt
Abstract
The document [RFC4908] proposes to rely on multiple Care-of Addresses
(CoAs) capabilities of Mobile IP [RFC6275] an Network Mobility (NEMO;
[RFC3963]) to enable Multihoming technology for Small-Scale Fixed
Networks. In the continuation of [RFC4908], this document specifies
a multiple proxy Care-of Addresses (pCoAs) extension for Proxy Mobile
IPv6 [RFC5213]. This extension allows a multihomed Mobile Access
Gateway (MAG) to register more than one proxy care-of-address to the
Local Mobility Anchor (LMA).
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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Internet-Drafts are draft documents valid for a maximum of six months
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This Internet-Draft will expire on June 18, 2016.
Copyright Notice
Copyright (c) 2015 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
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publication of this document. Please review these documents
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions and Terminology . . . . . . . . . . . . . . . . . 4
2.1. Conventions . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Example Call Flow . . . . . . . . . . . . . . . . . . . . 5
3.2. Traffic distribution schemes . . . . . . . . . . . . . . . 6
4. Protocol Extensions . . . . . . . . . . . . . . . . . . . . . 7
4.1. MAG Multipath-Binding Option . . . . . . . . . . . . . . . 7
4.2. MAG Identifier Option . . . . . . . . . . . . . . . . . . 9
4.3. New Status Code for Proxy Binding Acknowledgement . . . . 10
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
8.1. Normative References . . . . . . . . . . . . . . . . . . . 11
8.2. Informative References . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12
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1. Introduction
Using several links, the multihoming technology can improve
connectivity availability and quality of communications; the goals
and benefits of multihoming are as follows:
o Redundancy/Fault-Recovery
o Load balancing
o Load sharing
o Preferences settings
According to [RFC4908], users of Small-Scale Networks can take
benefit of multihoming using mobile IP [RFC6275] and Network Mobility
(NEMO) [RFC3963] architecture in a mobile and fixed networking
environment. This document was introducing the concept of multiple
Care-of Addresses (CoAs) [RFC5648] that have been specified since
then.
In the continuation of [RFC4908], a Proxy Mobile IPv6 [RFC5213] based
multihomed achitecture could be defined. The motivation to update
[RFC4908] with proxy Mobile IPv6 is to leverage on latest mobility
working group achievments, namely:
o using GRE as mobile tuneling, possibly with its key extension
[RFC5845] (a possible reason to use GRE is given on Section 3.2).
o using UDP encapsulation [RFC5844] in order to support NAT
traversal in IPv4 networking environment.
o Prefix Delegation mechanism [RFC7148].
Proxy Mobile IPv6 (PMIPv6) relies on two mobility entities: the
mobile access gateway (MAG), which acts as the default gateway for
the end-node and the local mobility anchor (LMA), which acts as the
topological anchor point. Point-to-point links are established,
using IP-in-IP tunnels, between MAG and LMA. Then, the MAG and LMA
are distributing traffic over these tunnels. All PMIPv6 operations
are performed on behalf of the end-node and its corespondent node, it
thus makes PMIPv6 well adapted to multihomed architecture as
considered in [RFC4908]. Taking the LTE and WLAN networking
environments as an example, the PMIPv6 based multihomed architecture
is depicted on Figure 1. Flow-1,2 and 3 are distributed either on
Tunnel-1 (over LTE) or Tunnel-2 (over WLAN), while Flow-4 is spread
on both Tunnel-1 and 2.
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Flow-1
|
|Flow-2 _----_
| | CoA-1 _( )_ Tunnel-1
| | .---=======( LTE )========\ Flow-1
| | | (_ _) \Flow-4
| | | '----' \
| | +=====+ \ +=====+ _----_
| '-| | \ | | _( )_
'---| MAG | | LMA |-( Internet )--
.---| | | | (_ _)
| .-| | / | | '----'
| | +=====+ / +=====+
| | | _----_ /
| | | CoA-2 _( )_ Tunnel-2 /
| | .---=======( WLAN )========/ Flow-2
| | (_ _) Flow-3
| | '----' Flow-4
|Flow-3
|
Flow0=-4
Figure 1: Multihomed MAG using Proxy Mobile IPv6
Current version of Proxy Mobile IPv6 does not allow a MAG to register
more than one proxy Care-of-Adresse to the LMA. In other words, only
one MAG/LMA link, i.e. IP-in-IP tunnel, tunnel can be used at the
same time. This document overcome this limitation by defining the
multiple proxy Care-of Addresses (pCoAs) extension for Proxy Mobile
IPv6.
2. Conventions and 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 mobility related terms used in this document are to be
interpreted as defined in [RFC5213], [RFC5844] and [RFC7148].
Additionally, this document uses the following terms:
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IP-in-IP
IP-within-IP encapsulation [RFC2473], [RFC4213]
3. Overview
3.1. Example Call Flow
Figure 2 is the callflow detailing multi-access support with PMIPv6.
The MAG in this example scenario is equipped with both WLAN and LTE
interfaces and is also configured with the MAG functionality. A
logical-NAI with ALWAYS-ON configuration is enabled on the MAG. The
mobility session that is created on the LMA is for the logical-NAI.
The IP hosts MN_1 and MN_2 are assigned IP addresses from the
delegated mobile network prefix.
+=====+ +=====+ +=====+ +=====+ +=====+ +=====+
| MN_1| | MN_2| | MAG | | WLAN| | LTE | | LMA |
+=====+ +=====+ +=====+ +=====+ +=====+ +=====+
| | | | | |
| | | | | |
| | | (1) ATTACH | | |
| | | <--------> | | |
| | | (2) ATTACH | |
| | | <---------------------->| |
| | | (3) PBU (NAI, MAG-NAI, DMNP, MMB) |
| | | ------------------------*----------> |
| | | (4) PBA (NAI, DMNP) |
| | | <-----------------------*----------- |
| | | (5) TUNNEL INTERFACE CREATION |
| | |-============== TUNNEL ==*===========-|
| | | |
| | | (6) PBU (NAI, MAG-NAI, DMNP, MMB) |
| | | -----------*-----------------------> |
| | | (7) PBA (NAI, DMNP) |
| | | <----------*------------------------ |
| | | (8) TUNNEL INTERFACE CREATION |
| | |-===========*== TUNNEL ==============-|
| (9) | |
| <------------------> | |
| | (10) | |
| |<-----------> | |
Figure 2: Functional Separation of the Control and User Plane
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3.2. Traffic distribution schemes
IP mobility protocols allow to establish the forwarding plane over
the WAN interfaces of a multihomed MAG. Then, traffic distribution
schemes define the way to distribute data packets over these paths
(i.e. IP tunnels). Traffic distribution can be managed either on a
per-flow or on a per-packet basis:
o per-flow traffic management: each IP flow (both upstream and
downstream) is mapped to a given mobile IP tunnel, corresponding
to a given WAN interface. This scenario is based on IP flow
mobility mechanism using the Flow binding extension [RFC6089].
The mobility anchor provides IP session continuity when an IP flow
is moved from one WAN interfaces to another. The flow binding
extension allows the IP mobility anchor and the MAG to exchange,
and synchronize, IP flow management policies (i.e. policy routing
rules associating traffic selectors [RFC6088] to mobility
bindings).
o Per-packet management: distribute the IP packets of a same IP
flow, or of a group of IP flows, over more than one WAN interface.
In this scenario, traffic management slightly differs from the
default mobile IP behaviour; the mobility entities (mobility
anchor and client) distribute packets, belonging to a same IP
flow, over more than one bindings simultaneously. The definition
of control algorithm of a Per-packet distribution scheme (how to
distribute packets) is out the scope of this document. When
operating at the packet level, traffic distribution scheme may
introduce packet latency and out-of-order delivery. It may
require the mobility entities (MAG and mobility anchor) to be able
to reorder (ans thus, to buffer) received packets before
delivering. A possible implementation is to use GRE as mobile
tunnelling mechanism, together with the GRE KEY option [RFC5845]
to add sequence number to GRE packets, and so, to allow the
receiver to perform reordering. However, more detailed buffering
and reordering considerations are out of the scope of this
document.
The traffic distribution scheme may require the MAG and the to
exchange interface metrics to make traffic steering decision.For
example, the MAG may send it link bandwidth to the mobility anchor,
so that the latter can make traffic forwarding decision accordingly.
In this case, the vendor specific mobility option [RFC5094] can be
used for that purpose.
Per-flow and per-packet distribution schemes are not exclusive
mechanisms; they can cohabit in the same multi-access system. For
example, High throughput services (e.g. video streaming) may benefit
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from per-packet distribution scheme, while some other may not.
Typically VoIP application are sensitive to latency and thus should
not be split over different WAN paths. In this situation, the
mobility entities (MAG and mobility anchor) must exchange traffic
management policies to associate distribution scheme, traffic and WAN
interface (physical or virtual). [RFC6088] and [RFC6089] define
traffic management on a flow basis but there is no such policy on a
per packet basis.
4. Protocol Extensions
4.1. MAG Multipath-Binding Option
The MAG Multipath-Binding option is a new mobility header option
defined for use with Proxy Binding Update and Proxy Binding
Acknowledgement messages exchanged between the local mobility anchor
and the mobile access gateway.
This mobility header option is used for requesting multipath support.
It indicates that the mobile access gateway is requesting the local
mobility anchor to register the current care-of address associated
with the request as one of the many care-addresses through which the
mobile access gateway can be reached. It is also for carrying the
information related to the access network associated with the care-of
address.
The MAG Multipath-Binding option has an alignment requirement of
8n+2. Its format is as shown in Figure 3:
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 | If-ATT | If-Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Binding-Id |B|O| RESERVED |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: MAG Multipath Binding Option
Type
<IANA-1> To be assigned by IANA.
Length
8-bit unsigned integer indicating the length of the option in
octets, excluding the type and length fields.
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This 8-bit field identifies the Access-Technology type of the
interface through which the mobile node is connected. The permitted
values for this are from the Access Technology Type registry defined
in [RFC5213].
This 8-bit field represents the interface label represented as an
unsigned integer. The mobile node identifies the label for each of
the interfaces through which it registers a CoA with the home agent.
When using static traffic flow policies on the mobile node and the
home agent, the label can be used for generating forwarding policies.
For example, the operator may have policy which binds traffic for
Application "X" needs to interface with Label "Y". When a
registration through an interface matching Label "Y" gets activated,
the home agent and the mobile node can dynamically generate a
forwarding policy for forwarding traffic for Application "X" through
mobile IP tunnel matching Label "Y". Both the home agent and the
mobile node can route the Application-X traffic through that
interface. The permitted values for If-Label are 1 through 255.
This 8-bit field is used for carrying the binding identifier. It
uniquely identifies a specific binding of the mobile node, to which
this request can be associated. Each binding identifier is
represented as an unsigned integer. The permitted values are 1
through 254. The BID value of 0 and 255 are reserved. The mobile
access gateway assigns a unique value for each of its interfaces and
includes them in the message.
This flag, if set to a value of (1), is to notify the local mobility
anchor to consider this request as a request to update the binding
lifetime of all the mobile node's bindings, upon accepting this
specific request. This flag MUST NOT be set to a value of (1), if
the value of the Registration Overwrite Flag (O) flag is set to a
value of (1).
This flag, if set to a value of (1), notifies the local mobility
anchor that upon accepting this request, it should replace all of the
mobile node's existing bindings with this binding. This flag MUST
NOT be set to a value of (1), if the value of the Bulk Re-
registration Flag (B) is set to a value of (1). This flag MUST be
set to a value of (0), in de-registration requests.
Reserved
This field is unused in this specification. The value MUST be set
to zero (0) by the sender and MUST be ignored by the receiver.
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4.2. MAG Identifier Option
The MAG Identifier option is a new mobility header option defined for
use with Proxy Binding Update and Proxy Binding Acknowledgement
messages exchanged between the local mobility anchor and the mobile
access gateway. This mobility header option is used for conveying
the MAG's identity.
This option does not have any alignment requirements.
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 | Subtype | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identifier ... ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: MAG Identifier Option
Type
<IANA-2> To be assigned by IANA.
Length
8-bit unsigned integer indicating the length of the option in
octets, excluding the type and length fields.
Subtype
One byte unsigned integer used for identifying the type of the
Identifier field. Accepted values for this field are the
registered type values from the Mobile Node Identifier Option
Subtypes registry.
Reserved
This field is unused in this specification. The value MUST be set
to zero (0) by the sender and MUST be ignored by the receiver.
Identifier
A variable length identifier of type indicated in the Subtype
field.
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4.3. New Status Code for Proxy Binding Acknowledgement
This document defines the following new Status Code value for use in
Proxy Binding Acknowledgement message.
CANNOT_SUPPORT_MULTIPATH_BINDING (Cannot Support Multipath Binding):
<IANA-4>
5. IANA Considerations
This document requires the following IANA actions.
o Action-1: This specification defines a new mobility option, the
MAG Multipath-Binding option. The format of this option is
described in Section 4.1. The type value <IANA-1> for this
mobility option needs to be allocated from the Mobility Options
registry at <http://www.iana.org/assignments/mobility-parameters>.
RFC Editor: Please replace <IANA-1> in Section 4.1 with the
assigned value and update this section accordingly.
o Action-2: This specification defines a new mobility option, the
MAG Identifier option. The format of this option is described in
Section 4.2. The type value <IANA-2> for this mobility option
needs to be allocated from the Mobility Options registry at
<http://www.iana.org/assignments/mobility-parameters>. RFC
Editor: Please replace <IANA-2> in Section 4.2 with the assigned
value and update this section accordingly.
o Action-4: This document defines a new status value,
CANNOT_SUPPORT_MULTIPATH_BINDING (<IANA-4>) for use in Proxy
Binding Acknowledgement message, as described in Section 4.3.
This value is to be assigned from the "Status Codes" registry at
<http://www.iana.org/assignments/mobility-parameters>. The
allocated value has to be greater than 127. RFC Editor: Please
replace <IANA-4> in Section 4.3 with the assigned value and update
this section accordingly.
6. Security Considerations
This specification allows a mobile access gateway to establish
multiple Proxy Mobile IPv6 tunnels with a local mobility anchor, by
registering a care-of address for each of its connected access
networks. This essentially allows the mobile node's IP traffic to be
routed through any of the tunnel paths and either based on a static
or a dynamically negotiated flow policy. This new capability has no
impact on the protocol security. Furthermore, this specification
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defines two new mobility header options, MAG Multipath-Binding option
and the MAG Identifier option. These options are carried like any
other mobility header option as specified in [RFC5213]. Therefore,
it inherits security guidelines from [RFC5213]. Thus, this
specification does not weaken the security of Proxy Mobile IPv6
Protocol, and does not introduce any new security vulnerabilities.
7. Acknowledgements
The authors of this draft would like to acknowledge the discussions
and feedback on this topic from the members of the DMM working group.
8. References
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>.
[RFC3963] Devarapalli, V., Wakikawa, R., Petrescu, A., and P.
Thubert, "Network Mobility (NEMO) Basic Support Protocol",
RFC 3963, DOI 10.17487/RFC3963, January 2005,
<http://www.rfc-editor.org/info/rfc3963>.
[RFC5094] Devarapalli, V., Patel, A., and K. Leung, "Mobile IPv6
Vendor Specific Option", RFC 5094, DOI 10.17487/RFC5094,
December 2007, <http://www.rfc-editor.org/info/rfc5094>.
[RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V.,
Chowdhury, K., and B. Patil, "Proxy Mobile IPv6",
RFC 5213, DOI 10.17487/RFC5213, August 2008,
<http://www.rfc-editor.org/info/rfc5213>.
[RFC5648] Wakikawa, R., Ed., Devarapalli, V., Tsirtsis, G., Ernst,
T., and K. Nagami, "Multiple Care-of Addresses
Registration", RFC 5648, DOI 10.17487/RFC5648,
October 2009, <http://www.rfc-editor.org/info/rfc5648>.
[RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", RFC 5844, DOI 10.17487/RFC5844, May 2010,
<http://www.rfc-editor.org/info/rfc5844>.
[RFC5845] Muhanna, A., Khalil, M., Gundavelli, S., and K. Leung,
"Generic Routing Encapsulation (GRE) Key Option for Proxy
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Mobile IPv6", RFC 5845, DOI 10.17487/RFC5845, June 2010,
<http://www.rfc-editor.org/info/rfc5845>.
[RFC6088] Tsirtsis, G., Giarreta, G., Soliman, H., and N. Montavont,
"Traffic Selectors for Flow Bindings", RFC 6088,
DOI 10.17487/RFC6088, January 2011,
<http://www.rfc-editor.org/info/rfc6088>.
[RFC6089] Tsirtsis, G., Soliman, H., Montavont, N., Giaretta, G.,
and K. Kuladinithi, "Flow Bindings in Mobile IPv6 and
Network Mobility (NEMO) Basic Support", RFC 6089,
DOI 10.17487/RFC6089, January 2011,
<http://www.rfc-editor.org/info/rfc6089>.
[RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
Support in IPv6", RFC 6275, DOI 10.17487/RFC6275,
July 2011, <http://www.rfc-editor.org/info/rfc6275>.
[RFC7148] Zhou, X., Korhonen, J., Williams, C., Gundavelli, S., and
CJ. Bernardos, "Prefix Delegation Support for Proxy Mobile
IPv6", RFC 7148, DOI 10.17487/RFC7148, March 2014,
<http://www.rfc-editor.org/info/rfc7148>.
8.2. Informative References
[RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in
IPv6 Specification", RFC 2473, DOI 10.17487/RFC2473,
December 1998, <http://www.rfc-editor.org/info/rfc2473>.
[RFC4213] Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms
for IPv6 Hosts and Routers", RFC 4213, DOI 10.17487/
RFC4213, October 2005,
<http://www.rfc-editor.org/info/rfc4213>.
[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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Authors' Addresses
Pierrick Seite
Orange
4, rue du Clos Courtel, BP 91226
Cesson-Sevigne 35512
France
Email: pierrick.seite@orange.com
Alper Yegin
Samsung
Istanbul
Turkey
Email: alper.yegin@partner.samsung.com
Sri Gundavelli
Cisco
170 West Tasman Drive
San Jose, CA 95134
USA
Email: sgundave@cisco.com
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