Internet DRAFT - draft-sijeon-dmm-stateless-mobility-function
draft-sijeon-dmm-stateless-mobility-function
DMM Working Group S. Jeon
Internet-Draft Sungkyunkwan University
Intended status: Standards Track September 11, 2017
Expires: March 15, 2018
Stateless mobility functions
draft-sijeon-dmm-stateless-mobility-function-01.txt
Abstract
This draft presents two use cases to start a talk of stateless
mobility function architecture in IETF DMM WG.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Mobility function architecture . . . . . . . . . . . . . . . 3
2.1. Integrated state with mobility function . . . . . . . . . 3
2.2. Separated state from mobility function . . . . . . . . . 3
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. Informative References . . . . . . . . . . . . . . . . . . . 4
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
A mobility function could be categorized stateful function and
stateless function. The stateful function maintains the state
information associated with a terminal or network situation while the
stateless function does not keep the state information but only
focusing on processing received signaling messages or data packets,
as a worker.
Combing the state with the worker in the mobility function has
basically been considered in many network architectures for easier
implementation and negligible latency for accessing the state
database without external signaling messages. However, it is
nowadays challenging as it tackles the flexibility for network
scaling and other enhanced operation support.
Separating the control-plane and user-plane makes a progress for the
flexible network control and provisioning. That is, a routing
controller with holistic view can take a decision of forwarding
behavior in the network entities. Stateless user-plane architecture
is proposed in [I-D.matsushima-stateless-uplane-vepc], suggesting a
mobile architecture that the user-plane network is governed by
virtualized EPC decorated with mobility control-plane functions only.
The state information the vEPC is holding is transferred by BGP
routing to the user-plane architecture. Therefore, the user-plane
architecture is totally abstracted and becomes state free, supporting
high flexibility in network scaling.
Mobility architecture is composed of many control-plane functions.
Scale-in/scale-out of those functions is of importance for elastic
function resource handling and management (e.g., load balancing).
User-plane functions does not generically hold the state information
much, so it is relatively easier to do scaling but it is challenging
to scale with mobility control-plane functions. Separating the state
information from the control-plane functions could facilitate
flexible function resource provisioning and expect further enhanced
scenarios such as VNF mobility and migration procedure easier.
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The main objective of this draft is to bring a broad discussion in
IETF DMM WG, identifying what needs and requirements for the state
separation from a mobility function are existing and what use cases
could be meaningful, finally bearing a work item. In this draft, we
start with two cases; i) mobility control-plane function integrated
with the state information and ii) mobility control-plane function
separated from the state information. From the two cases, we check
the mentioned aspects.
2. Mobility function architecture
2.1. Integrated state with mobility function
Fig. 1 shows the state information is integrated in the mobility
control-plane function. Suppose that the mobility control-plane
function is composed of state and worker where the work is dedicated
to the processing of signaling messages or data packets without
concerning or maintaining the state. When the function is
instantiated, the state is also initialized within the function. On
the other hand, the function needs to be shut down due to some
maintenance purpose and the same kinds of a new function is supposed
to be initiated, the managed mobility state associated with mobile
terminals should be moved to the newly initiated mobility control-
plane function through a migration procedure in this case.
+-------------+ +-------------+
| State info. | | State info. |
+-------------+ +-------------+
| Worker for | | Worker for |
| MCP function| | MCP function|
+-------------+ +-------------+
Fig. 1. The mobility function integrated with the state information
2.2. Separated state from mobility function
Fig. 2 shows the state information is separated from the mobility
control-plane function, thus the worker for mobility control-plane
function remains in the function. The relationship between the state
database and worker can be defined by internal interface or external
interface. Following the same scenario described in 2.1, for a need
of replacing with a new worker or for scaling out/in, maintaining the
state is not constrained, so facilitating various flexibility
scenarios.
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+-------------+
| State info. |
+-------------+
| ^ ^ |
| | | |
v | | v
+-------------+ +-------------+
| Worker for | | Worker for |
| MCP function| | MCP function|
+-------------+ +-------------+
Fig. 2. The mobility function separated from the state information
3. IANA Considerations
This document currently makes no request of IANA.
4. Security Considerations
5. Informative References
[ETSI.NFV-VNFA]
"Network Functions Virtualisation (NFV); Virtual Network
Functions Architecture, ETSI GS NFV-SWA 001, v1.1.1",
December 2014.
[I-D.matsushima-stateless-uplane-vepc]
Matsushima, S. and R. Wakikawa, "Stateless user-plane
architecture for virtualized EPC (vEPC)", draft-
matsushima-stateless-uplane-vepc-06 (work in progress),
March 2016.
Author's Address
Seil Jeon
Sungkyunkwan University
2066 Seobu-ro, Jangan-gu
Suwon, Gyeonggi-do
Korea
Email: seiljeon@skku.edu
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