Internet DRAFT - draft-wakikawa-netext-pmip-cp-up-separation
draft-wakikawa-netext-pmip-cp-up-separation
NETEXT WG R. Wakikawa
Internet-Draft Softbank Mobile
Intended status: Standards Track R. Pazhyannur
Expires: January 17, 2014 S. Gundavelli
Cisco
July 16, 2013
Separation of Control and User Plane for Proxy Mobile IPv6
draft-wakikawa-netext-pmip-cp-up-separation-00.txt
Abstract
This document describes splitting of Control Plane (CP) and User
Plane (UP) for a Proxy Mobile IPv6 based network infrastructure.
Existing specifications allow a MAG to perform splitting of its
control and user plane using Alternate Care of address mobility
option for IPv6, or Alternate IPv4 Care of Address option for IPv4.
However, the current specification does not have semantics for
allowing the LMA to perform such functional split. To realize this
requirement, this specification defines a mobility option that
enables a local mobility anchor to provide an alternate LMA address
to be used for the bi-directional tunnel between the MAG and LMA.
With this extension, a local mobility anchor will be able to use an
IP address for its user plane which is different than what is used
for the control plane.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 17, 2014.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions and Terminology . . . . . . . . . . . . . . . . . 4
2.1. Conventions . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
3. LMA User Plane Address Mobility Option . . . . . . . . . . . 5
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.1. Normative References . . . . . . . . . . . . . . . . . . 6
7.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
Widely deployed mobility management systems for wireless
communications have isolated the path for forwarding data packets
from the control plane signaling for mobility management. To realize
this requirement, Proxy Mobile IPv6 requires that the control plane
functions of the local mobility anchor to be addressable at a
different IP address than the IP address used for the user plane.
However, the current specification does not have semantics for
allowing the LMA to perform such functional split. The local
mobility anchor is required to associate the IP address of the tunnel
source with the target IP address of the control messages received
from the MAG. Note that the concept of control- and user- planes are
well established and understood in cellular networks.
A PMIPv6 infrastructure contains of two primary entities: MAG and
LMA. The interface between MAG and LMA consists of two components:
control plane and user plane. The control plane is responsible for
signaling messages between MAG and LMA such as the Proxy Binding
Update and Proxy Binding Acknowledge messages to establish a mobility
binding. In addition, the control plane components in the MAG and
LMA are also responsible for setting up and tearing down of the bi-
directional tunnel between the MAG and LMA. The user plane is
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responsible for forwarding the mobile node's IP packets between the
MAG and the LMA over the bi-directional tunnel.
In most deployments, the control plane and user plane components (of
the MAG and LMA) are co-located in the same physical entity.
However, there are deployments where it is desirable to have the
control and user plane of the MAG and LMA in separate physical
entities. For example, in a WLAN (Wireless LAN) deployment, it may
be desirable to have the control plane component of the MAG to be on
Access Controller (also sometimes referred to as Wireless LAN
Controller) while the user plane component of the MAG on the WLAN
Access Point. This would enable all the signaling messages to the
LMA to be centralized while the user plane would be distributed
across the multiple Access Points. Similarly there is a case to
split the control and user plane component of the LMA motivated by
different scaling requirements on the control and user plane
components or need to centralize the control plane in one geo-
location while distributing the user plane component across multiple
geo-locations
[RFC6463] and [RFC6275] contains a mechanism of splitting the control
and user plane in MAG. Specifically, [RFC6463] defines an Alternate
IPv4 Proxy Care of Address Option while [RFC6275] defines an
Alternate Care of Address for IPv6 address. The MAG can provide an
Alternate Care of Address in the Proxy Binding Update (PBU) and if
the LMA supports this option then a bidirectional tunnel is setup
between the LMA address and the MAG's alternate Care of address.
However, there is no corresponding option for the LMA to provide an
alternate address to the MAG.
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CP: Control Plane
UP: User Plane
+------------+ +------------+
| MAG | | LMA |
| +--------+ | | +--------+ |
+------+ | | MAG-CP |-|-------------|-| LMA-CP | | _----_
| MN | | | | | PMIPv6 | | | | _( )_
| |-----| +--------+ | | +--------+ |===( Internet )
+------+ | : | | : | (_ _)
| +--------+ | | +--------+ | '----'
| | MAG-UP |-|-------------|-| LMA-UP | |
| | | |GRE/IP-in-IP | | | |
| +--------+ | | +--------+ |
+------------+ +------------+
Figure 1: Functional Split of the Control and User Plane
This specification therefore defines a new mobility option that
enables a local mobility anchor to provide an alternate LMA address
to be used for the bi-directional tunnel between the MAG and LMA.
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 the mobility related terms used in this document are to be
interpreted as defined in [RFC5213] and [RFC5844]. 3GPP terms can be
found at [RFC6459]. Additionally, this document uses the following
terms:
LMA User Plane Address (LMA-UPA)
The IP address on the LMA that is used for establishing tunnels
with the mobile access gateway.
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3. LMA User Plane Address Mobility Option
A new mobility header option, LMA User Plane Address mobility option
is defined for use with Proxy Binding Acknowledgment message sent
from the local mobility anchor to the mobile access gateway. This
option is used for notifying the LMA's user plane IPv4/IPv6 address.
There can be multiple instances of the LMA User Plane Address
mobility option present in the message, one for IPv4 and the other
for IPv6 transport.
The LMA User Plane Address mobility option has an alignment
requirement of 8n+2. Its format is as follows:
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 | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
. .
+ LMA User Plane Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
To be assigned by IANA.
Length
8-bit unsigned integer indicating the length of the option in
octets, excluding the type and length fields.
Reserved
This field is unused for now. The value MUST be initialized to 0
by the sender and MUST be ignored by the receiver.
LMA User Plane Address
Contains the IPv4/IPv6 user plane address of the LMA.
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4. IANA Considerations
This document requires the following IANA action.
o Action-1: This specification defines a new Mobility Header option,
LMA User Plane Address mobility option. This mobility option is
described in Section 3. The type value <IANA-1> for this message
needs to be allocated from the Mobility Header Types registry at
http://www.iana.org/assignments/mobility-parameters. RFC Editor:
Please replace <IANA-1> in Section 3 with the assigned value, and
update this section accordingly.
5. Security Considerations
The LMA User Plane Address mobility Option defined in this
specification is for use in Proxy Binding Acknowledgement message.
This option is carried like any other mobility header option as
specified in [RFC5213]. Therefore, it inherits from [RFC5213] its
security guidelines and does not require any additional security
considerations.
6. Acknowledgements
Authors would like Acknowledge all the discussions on this topic in
the NETLMM Working group.
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.
[RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", RFC 5844, May 2010.
7.2. Informative References
[RFC6275] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support
in IPv6", RFC 6275, July 2011.
[RFC6459] Korhonen, J., Soininen, J., Patil, B., Savolainen, T.,
Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation
Partnership Project (3GPP) Evolved Packet System (EPS)",
RFC 6459, January 2012.
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[RFC6463] Korhonen, J., Gundavelli, S., Yokota, H., and X. Cui,
"Runtime Local Mobility Anchor (LMA) Assignment Support
for Proxy Mobile IPv6", RFC 6463, February 2012.
Authors' Addresses
Ryuji Wakikawa
Softbank Mobile
1-9-1,Higashi-Shimbashi,Minato-Ku
Tokyo 105-7322
Japan
Email: ryuji.wakikawa@gmail.com
Rajesh S. Pazhyannur
Cisco
170 West Tasman Drive
San Jose, CA 95134
USA
Email: rpazhyan@cisco.com
Sri Gundavelli
Cisco
170 West Tasman Drive
San Jose, CA 95134
USA
Email: sgundave@cisco.com
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