Internet DRAFT - draft-ietf-dmm-deployment-models
draft-ietf-dmm-deployment-models
DMM WG S. Gundavelli
Internet-Draft Cisco
Intended status: Informational S. Jeon
Expires: November 17, 2018 Sungkyunkwan University
May 16, 2018
DMM Deployment Models and Architectural Considerations
draft-ietf-dmm-deployment-models-04.txt
Abstract
This document identifies the deployment models for Distributed
Mobility Management architecture.
Status of This Memo
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This Internet-Draft will expire on November 17, 2018.
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Table of Contents
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions and Terminology . . . . . . . . . . . . . . . . . 3
2.1. Conventions . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
3. DMM Architectural Overview . . . . . . . . . . . . . . . . . 4
3.1. DMM Service Primitives . . . . . . . . . . . . . . . . . 4
3.2. DMM Functions and Interfaces . . . . . . . . . . . . . . 5
3.2.1. Home Control-Plane Anchor (Home-CPA): . . . . . . . . 5
3.2.2. Home Data-Plane Anchor (Home-DPA): . . . . . . . . . 6
3.2.3. Access Control Plane Node (Access-CPN) . . . . . . . 6
3.2.4. Access Data Plane Node (Access-DPN) . . . . . . . . . 6
3.2.5. DMM Functions Mapping to Other Architectures . . . . 6
4. Deployment Models . . . . . . . . . . . . . . . . . . . . . . 8
4.1. Model-1: Split Home Anchor Mode . . . . . . . . . . . . . 8
4.2. Model-2: Separated Control and User Plane Mode . . . . . 9
4.3. Model-3: Centralized Control Plane Mode . . . . . . . . . 10
4.4. Model-4: Data Plane Abstraction Mode . . . . . . . . . . 10
4.5. Model-5: On-Demand Control Plane Orchestration Mode . . . 11
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
6. Security Considerations . . . . . . . . . . . . . . . . . . . 13
7. Work Team . . . . . . . . . . . . . . . . . . . . . . . . . . 13
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
9.1. Normative References . . . . . . . . . . . . . . . . . . 14
9.2. Informative References . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Overview
One of the key aspects of the Distributed Mobility Management (DMM)
architecture is the separation of control plane (CP) and data plane
(DP) functions of a network element. While data plane elements
continue to reside on customized networking hardware, the control
plane resides as a software element in the cloud. This is usually
referred to as CP-DP separation and is the basis for the IETF's DMM
Architecture. This approach of centralized control plane and
distributed data plane allows elastic scaling of control plane and
efficient use of common data plane that is agnostic to access
architectures.
This document identifies the functions in the DMM architecture and
the supported deployment models.
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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 are to interpreted as defined in
[RFC6275], [RFC5213], [RFC5844], [RFC7333], [RFC7665], [RFC7429],
[RFC8300] and [I-D.ietf-dmm-fpc-cpdp]. Additionally, this document
uses the following terms:
Home Control-Plane Anchor (Home-CPA or H-CPA)
The Home-CPA function hosts the mobile node (MN)'s mobility
session. There can be more than one mobility session for a mobile
node and those sessions may be anchored on the same or different
Home-CPA's. The home-CPA will interface with the home-DPA for
managing the forwarding state.
Home Data Plane Anchor (Home-DPA or H-DPA)
The Home-DPA is the topological anchor for the MN's IP address/
prefix(es). The Home-DPA is chosen by the Home-CPA on a session-
basis. The Home-DPA is in the forwarding path for all the mobile
node's IP traffic.
Access Control Plane Node (Access-CPN or A-CPN)
The Access-CPN is responsible for interfacing with the mobile
node's Home-CPA and with the Access-DPN. The Access-CPN has a
protocol interface to the Home-CPA.
Access Data Plane Node (Access-DPN or A-DPN)
The Access-DPN function is hosted on the first-hop router where
the mobile node is attached. This function is not hosted on a
layer-2 bridging device such as a eNode(B) or Access Point.
Routing Controller (RC)
The Routing Controller is a centralized control entity, which is
able to instruct the forwarding behavior for mobility management
in Home-DPA and Access-DPN.
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Mobility Controller (MC)
The Mobility Controller is a function entity, which is able to
manage the orchestration of Home-CPA and Access-CPN functions.
3. DMM Architectural Overview
Following are the key goals of the Distributed Mobility Management
architecture.
1. Separation of control and data Plane
2. Aggregation of control plane for elastic scaling
3. Distribution of the data plane for efficient network usage
4. Elimination of mobility state from the data plane
5. Dynamic selection of control and data plane nodes
6. Enabling the mobile node with network properties
7. Relocation of anchor functions for efficient network usage
3.1. DMM Service Primitives
The functions in the DMM architecture support a set of service
primitives. Each of these service primitives identifies a specific
service capability with the exact service definition. The functions
in the DMM architecture are required to support a specific set of
service primitives that are mandatory for that service function. Not
all service primitives are applicable to all DMM functions. The
below table as shown in Fig. 1 identifies the service primitives that
each of the DMM function SHOULD support. The marking "X" indicates
the service primitive on that row needs to be supported by the
identified DMM function on the corresponding column; for example, the
IP address management MUST be supported by Home-CPA function. The
NSH Classifier denotes the SFC entity that performs the
classification of a service flow, defined in [RFC7665].
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+=================+=======+=======+=======+=======+=======+=======+
| Service | H-CPA | H-DPA | A-CPN | A-DPN | MC | RC |
| Primitive | | | | | | |
+=================+=======+=======+=======+=======+=======+=======+
| IP Management | X | | | | X | |
+-----------------+-------+-------+-------+-------+-------+-------+
| IP Anchoring | | X | | | | |
+-----------------+-------+-------+-------+-------+-------+-------+
| MN Detection | | | X | X | | |
+-----------------+-------+-------+-------+-------+-------+-------+
| Routing | | X | | X | | |
+-----------------+-------+-------+-------+-------+-------+-------+
| Tunneling | | X | | X | | |
+-----------------+-------+-------+-------+-------+-------+-------+
| QoS Enforcement | | X | | X | | |
+-----------------+-------+-------+-------+-------+-------+-------+
| FPC Client | X | | X | | X | |
+-----------------+-------+-------+-------+-------+-------+-------+
| FPC Agent | | X | | X | | X |
+-----------------+-------+-------+-------+-------+-------+-------+
| NSH Classifier | | X | | X | | |
+-----------------+-------+-------+-------+-------+-------+-------+
Figure 1: Role or capability of DMM functions
3.2. DMM Functions and Interfaces
3.2.1. Home Control-Plane Anchor (Home-CPA):
The Home-CPA function hosts the mobile node's mobility session.
There can be more than one mobility session for a mobile node and
those sessions may be anchored on the same or different Home-CPA's.
The home-CPA will interface with the home-dpa for managing the
forwarding state.
There can be more than one Home-CPA serving the same mobile node at a
given point of time, each hosting a different control plane session.
The Home-CPA is responsible for life cycle management of the session,
interfacing with the policy infrastructure, policy control and
interfacing with the Home-DPA functions.
The Home-CPA function typically stays on the same node. In some
special use-cases (Ex: Geo-Redundancy), the session may be migrated
to a different node and with the new node assuming the Home-CPA role
for that session.
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3.2.2. Home Data-Plane Anchor (Home-DPA):
The Home-DPA is the topological anchor for the mobile node's IP
address/prefix(es). The Home-DPA is chosen by the Home-CPA/MC on a
session-basis. The Home-DPA is in the forwarding path for all the
mobile node's IP traffic.
As the mobile node roams in the mobile network, the mobile node's
access-DPN may change, however, the Home-DPA does not change, unless
the session is migrated to a new node.
The Home-DPA interfaces with the Home-CPA/MC for all IP forwarding
and QoS rules enforcement.
The Home-DPA and the Access-DPN functions may be collocated on the
same node.
3.2.3. Access Control Plane Node (Access-CPN)
The Access-CPN is responsible for interfacing with the mobile node's
Home-CPA and with the Access-DPN. The Access-CPN has a protocol
interface to the Home-CPA.
The Access-CPN is responsible for the mobile node's Home-CPA
selection based on: Mobile Node's Attach Preferences, Access and
Subscription Policy, Topological Proximity and Other Considerations.
The Access-CPN function is responsible for MN's service
authorization. It will interface with the access network
authorization functions.
3.2.4. Access Data Plane Node (Access-DPN)
The Access-DPN function is hosted on the first-hop router where the
mobile node is attached. This function is not hosted on a layer-2
bridging device such as a eNode(B) or Access Point.
The Access-DPA will have a protocol interface to the Access-CPA.
The Access-DPN and the Home-DPA functions may be collocated on the
same node.
3.2.5. DMM Functions Mapping to Other Architectures
Following table identifies the potential mapping of DMM functions to
protocol functions in other system architectures.
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+=======+=========+========+=========+=============+==========+=======+
| Func. | PMIPv6 | MIPv6 | IPsec | 3GPP-SAE | BBF | 5GC |
+=======+=========+========+=========+=============+==========+=======+
| H-CPA | LMA-CPA | HA-CPA | IKE-CPA | PGW-CPA/MME | BNG-CPA |AMF/SMF|
+-------+---------+--------+---------+-------------+----------+-------+
| H-DPA | LMA-DPA | HA-DPA | IKE-DPA | PGW-DPA | BNG-DPA | UPF |
+-------+---------+--------+---------+-------------+----------+-------+
| A-CPN | MAG-CPN | - | - | SGW-CPN | RG-CPN | SMF |
+-------+---------+--------+---------+-------------+----------+-------+
| A-DPN | MAG-DPN | - | - | SGW-DPN | RG-DPN | UPF |
+-------+---------+--------+---------+-------------+----------+-------+
Figure 2: Mapping of DMM functions in other system architectures
Mapping from the DMM functions to network components in PMIPv6,
MIPv6, IPsec, Broadband Forum (BBF) can be given straight-forward.
In the 3GPP System Architecture Evolution (SAE), H-CPA functionality
is charged by PGW-CPA and Mobility Management Entity (MME), as MME is
the key control-plane node involving in such as location management,
handoff management, selection of SGW/PGW as well as authorization of
UEs. But PGW-CPA is in charge of tunnel control based on UE's
subscription and policy between SGW and PGW. The rest of the 3GPP
SAE network components are as given in Fig. 2.
The 3GPP Release 15 introduces the Service-Based Architecture (SBA)
for 5G networks. The 3GPP 5G architecture can be represented by
reference point or service-based interfaces [_3GPP.23.501]. Allowing
the service-based interface provides greater flexibility for updates
and extensions of the 5G control plane system by operator's need or
request. The architecture introduces various kinds of network
functions granularized in the CP/DP separation concept. In Fig. 2,
Access and Mobility Management Function (AMF), Session Management
Function (SMF), and User Plane Function (UPF) are picked up among all
the network functions introduced in the 5G SBA for mapping to the DMM
functions.
AMF and SMF take major roles for mobility management in control
plane. AMF manages access control and mobility and includes network
slice selection functionality. SMF manages sessions based on UE's
subscription and network policy and is in charge of IP address
allocation management. UPF is the data plane node, which works for
data packet handling based on forwarding policy regulated by control
plane nodes such as AMF and SMF, etc.
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4. Deployment Models
This section identifies the key deployment models for the DMM
architecture.
4.1. Model-1: Split Home Anchor Mode
In this model, the control and the data plane functions of the home
anchor are separated and deployed on different nodes. The control
plane function of the Home anchor is handled by the Home-CPA and
where as the data plane function is handled by the Home-DPA. In this
model, the access node operates in the legacy mode with the
integrated control and user plane functions.
The FPC interface defined in [I-D.ietf-dmm-fpc-cpdp] allows the
control plane functions to interact with the data plane for the
subscriber's forwarding state management.
+============+
| Policy |
. . . . . . .| Function |. . . . . . .
. +============+ .
. .
. .
+============+ {PMIPv6/GTP} +============+
| |- - - - - - - - - - - - -| Home-CPA |
| | +============+
| | .
| | . FPC
| Access Node| .
| | .
| (CPN + DPN)| .
| | +============+
| Legacy |. . . . . . . . . . . . .| Home-DPA |
+============+ UP {Tunnel/Route} +============+
.
.
+--+
|MN|
+--+
Figure 3: Split Home Anchor Mode
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4.2. Model-2: Separated Control and User Plane Mode
In this model, the control and the data plane functions on both the
home anchor and the access node are seperated and deployed on
different nodes. The control plane function of the Home anchor is
handled by the Home-CPA whereas the data plane function is handled by
the Home-DPA. The control plane function of the access node is
handled by the Access-CPN and where as the data plane function is
handled by the Access-DPN.
The FPC interface defined in [I-D.ietf-dmm-fpc-cpdp] allows the
control plane functions of the home and access nodes to interact with
the respective data plane functions for the subscriber's forwarding
state management.
+============+
| Policy |
. . . . . . .| Function |. . . . . . .
. +============+ .
. .
. .
. .
. .
+============+ {PMIPv6/GTP} +============+
| Access-CPN |- - - - - - - - - - - - | Home-CPA |
+============+ +============+
. .
. FPC . FPC
. .
. .
. .
+============+ +============+
| Access-DPN |. . . . . . . . . . . | Home-DPA |
+============+ UP {Tunnel/Route} +============+
.
.
+--+
|MN|
+--+
Figure 4: Seperated Control and User Plane Mode
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4.3. Model-3: Centralized Control Plane Mode
In this model, the control-plane functions of the home and the access
nodes are collapsed. This is a flat architecture with no signaling
protocol between the access node and home anchors. The interface
between the Home-CPA and the Access-DPN is internal to the system.
The FPC interface defined in [I-D.ietf-dmm-fpc-cpdp] allows the
mobility controller to interact with the respective data plane
functions for the subscriber's forwarding state management.
+=======================+ +============+
| Home-CPA + Access-CPN | | Policy |
| |-----| Function |
+=======================+ +============+
.
. .
. .
FPC . . FPC
. .
. .
+============+ +============+
| Access-DPN |. . . . . . . . . .| Home-DPA |
+============+ UP {Tunnel/Route} +============+
.
.
+--+
|MN|
+--+
Figure 5: Centralized Control Plane Mode
4.4. Model-4: Data Plane Abstraction Mode
In this model, the data plane network is completely abstracted from
the control plane. There is a new network element, Routing
Controller which abstracts the entire data plane network and offers
data plane services to the control plane functions. The control
plane functions, Home-CPA and the Access-CPN interface with the
Routing Controller for the forwarding state management.
The FPC interface defined in [I-D.ietf-dmm-fpc-cpdp] allows the Home-
CPA and Access-CPN functions to interface with the Routing Controller
for subscriber's forwarding state management.
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+============+
| Policy |
. . . . . . .| Function |. . . . . . .
. +============+ .
. .
. .
. .
+============+ {PMIPv6/GTP} +============+
| Access-CPN |- - - - - - - - - - - - | Home-CPA |
+============+ +============+
. .
. .
. .
. +============+ .
. . . . . . | Routing | . . . . . . .
| Controller |
+============+
.
. .
. . BGP/Others
. .
. .
. .
+============+ +============+
| Access-DPN |. . . . . . . . . .| Home-DPA |
+============+ UP {Tunnel/Route} +============+
.
.
+--+
|MN|
+--+
Figure 6: Data Plane Abstraction Mode
4.5. Model-5: On-Demand Control Plane Orchestration Mode
In this model, there is a new function Mobility Controller which
manages the orchestration of Access-CPN and Home-CPA functions. The
Mobility Controller allocates the Home-CPA and Access-DPN
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+ - - - - - - - - - - - - - - - - - - - - - - - - - - -+
| +----------+ +----------+ +----------+ |
|Access-CPN| |Access-CPN| |Access-CPN|
| +----------+ +----------+ +----------+ |
| +----------+ +----------+ +----------+ |
| Home-CPA | | Home-CPA | | Home-CPA |
| +----------+ +----------+ +----------+ |
+ - - - - - - - - - - - - - - - - - - - - - - - - - - -+
. .
. .
. .
. +============+ +============+
. | Mobility | | Policy |
. | Controller |-----| Function |
. +============+ +============+
.
.
.
. +============+
. . . . . .| Routing |
| Controller |
+============+
.
.
.
+ - - - - - - - - - - - - - - - - - - - - - - - - - - -+
| +----------+ +----------+ +----------+ |
|Access-DPN| |Access-DPN| |Access-DPN|
| +----------+ +----------+ +----------+ |
| +----------+ +----------+ +----------+ |
| Home-DPA | | Home-DPA | | Home-DPA |
| +----------+ +----------+ +----------+ |
+ - - - - - - - - - - - - - - - - - - - - - - - - - - -+
Figure 7: On-Demand CP Orchestration Mode
5. IANA Considerations
This document does not require any IANA actions.
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6. Security Considerations
The control-plane messages exchanged between a Home-CPA and the Home-
DPA must be protected using end-to-end security associations with
data-integrity and data-origination capabilities.
IPsec ESP in transport mode with mandatory integrity protection
should be used for protecting the signaling messages. IKEv2 should
be used to set up security associations between the Home-CPA and
Home-DPA.
There are no additional security considerations other than what is
presented in the document.
7. Work Team
This document reflects contributions from the following work team
members:
Younghan Kim
younghak@ssu.ac.kr
Vic Liu
liuzhiheng@chinamobile.com
Danny S Moses
danny.moses@intel.com
Marco Liebsch
liebsch@neclab.eu
Carlos Jesus Bernardos Cano
cjbc@it.uc3m.es
8. Acknowledgements
This document is a result of DMM WT#4 team discussions and ideas
taken from several DMM WG presentations and documents including,
draft-sijeon-dmm-deployment-models, draft-liu-dmm-deployment-scenario
and others. The work teams would like to thank the authors of these
documents and additionally the discussions in DMM Working group that
helped shape this document.
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9. References
9.1. 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,
<https://www.rfc-editor.org/info/rfc2119>.
9.2. Informative References
[_3GPP.23.501]
3GPP, "System Architecture for the 5G System", 3GPP
TS 23.501 15.0.0, December 2018,
<http://www.3gpp.org/ftp/Specs/html-info/23501.htm>.
[I-D.ietf-dmm-fpc-cpdp]
Matsushima, S., Bertz, L., Liebsch, M., Gundavelli, S.,
Moses, D., and C. Perkins, "Protocol for Forwarding Policy
Configuration (FPC) in DMM", draft-ietf-dmm-fpc-cpdp-10
(work in progress), March 2018.
[RFC5213] Gundavelli, S., Ed., Leung, K., Devarapalli, V.,
Chowdhury, K., and B. Patil, "Proxy Mobile IPv6",
RFC 5213, DOI 10.17487/RFC5213, August 2008,
<https://www.rfc-editor.org/info/rfc5213>.
[RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", RFC 5844, DOI 10.17487/RFC5844, May 2010,
<https://www.rfc-editor.org/info/rfc5844>.
[RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
2011, <https://www.rfc-editor.org/info/rfc6275>.
[RFC7333] Chan, H., Ed., Liu, D., Seite, P., Yokota, H., and J.
Korhonen, "Requirements for Distributed Mobility
Management", RFC 7333, DOI 10.17487/RFC7333, August 2014,
<https://www.rfc-editor.org/info/rfc7333>.
[RFC7429] Liu, D., Ed., Zuniga, JC., Ed., Seite, P., Chan, H., and
CJ. Bernardos, "Distributed Mobility Management: Current
Practices and Gap Analysis", RFC 7429,
DOI 10.17487/RFC7429, January 2015,
<https://www.rfc-editor.org/info/rfc7429>.
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[RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function
Chaining (SFC) Architecture", RFC 7665,
DOI 10.17487/RFC7665, October 2015,
<https://www.rfc-editor.org/info/rfc7665>.
[RFC8300] Quinn, P., Ed., Elzur, U., Ed., and C. Pignataro, Ed.,
"Network Service Header (NSH)", RFC 8300,
DOI 10.17487/RFC8300, January 2018,
<https://www.rfc-editor.org/info/rfc8300>.
Authors' Addresses
Sri Gundavelli
Cisco
170 West Tasman Drive
San Jose, CA 95134
USA
Email: sgundave@cisco.com
Seil Jeon
Sungkyunkwan University
2066 Seobu-ro, Jangan-gu
Suwon, Gyeonggi-do
Korea
Email: seiljeon@skku.edu
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