Network Working Group J. Shin
R. Hwang
J. Lee
Internet Draft SK Telecom
Intended status: Informational
June 30, 2014
ACTN Use-case for Mobile Virtual Network Operation for Multiple
Domains in a Single Operator Network
draft-shin-actn-mvno-multi-domain-00.txt
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Abstract
This document provides a use-case that addresses the need for
virtual network operation for mobile operators, which is facilitated
by the application of network abstraction. These abstractions shall
create a virtual network operation environment supporting mobile
operators in viewing, managing and operating multi-domains of many
dimensions (e.g., radio access, backhaul transport, mobile DC edge,
mobile DC core, packet/optical transport for DC interconnect, etc.)
as a single virtualized network.
This use-case considers the application of these abstractions and
the need for the associated operational mechanisms within the
network of a single operator.
Table of Contents
1. Introduction...................................................2
2. Operational Challenges and Issues in Mobile Operator's Multi-
domain Networks...................................................4
3. Virtual Network Operations for Mobile Operators' Networks......7
4. References.....................................................8
5. Contributors...................................................8
Author's Addresses................................................8
Intellectual Property Statement...................................9
Disclaimer of Validity............................................9
1. Introduction
Mobile network operators build and operate their network using
multiple domains in different dimensions. From a network
domain/technology point of view, mobile services/applications
traverse many different domains such as radio access, backhaul
transport, mobile DC edge, packet/optical backbone transport for DC
interconnect, mobile DC core, etc. Due to this diversity of
technology domains (e.g., radio, packet, optical, etc.) and the
complex organizational boundaries for operations (e.g., access,
backhaul, core transport, data center, etc.), the efficient
operation of the services/applications spanning several of these
domains has been a challenge for mobile operators.
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In addition, multi-vendor issue adds another dimension of
complexity. Both interoperability and operational concerns at the
control and data planes have increased operational complexity and
the OpEx.
Moreover, the widespread deployment of middle boxes (e.g. edge cache,
firewall etc.) inside the DC edge and core edge will be achieved due
to tightly-coupled interaction with higher layer protocols and
transport control protocols (i.e. GMPLS, RSVP, etc.)
With the aforementioned situations, the introduction of new services
and applications, often requiring connections that traverse multiple
domains, necessitates significant planning, and several manual
operations to interface different administrative zones, vendor
equipment and transport technology.
This document provides a use-case that addresses the need for
facilitating the application of virtual network abstractions to
mobile network operators. These abstractions shall create a
virtualized network operation environment supporting mobile
operators in viewing and controlling multi-domains of many
dimensions (e.g., radio access, backhaul transport, mobile DC edge,
mobile DC core, packet/optical transport for DC interconnect, etc.)
as a single virtualized network. This use-case considers the
application of these abstractions within the network of a single
operator.
This use-case is a part of the overarching work, called Abstraction
and Control of Transport Networks (ACTN). The goal of ACTN is to
facilitate virtual network operation by:
. The creation of a virtualized environment allowing operators to
view the abstraction of the underlying multi-admin, multi-
vendor, multi-technology networks and
. The operation and control/management of these multiple networks
as a single virtualized network.
This will accelerate rapid service deployment of new services,
including more dynamic and elastic services, and improve overall
network operations and scaling of existing services.
Related documents are the ACTN-framework [ACTN-Frame] and the
problem statement [ACTN-PS].
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2. Operational Challenges and Issues in Mobile Operator's Multi-domain
Networks
Figure 1 depicts an illustrative example for mobile operator's
multi-domain networks.
+--------------+
| Internet |
| Core |
| Network |
| Domain 6 |
| (Vendor G) |
+--------------+
*
+----------+ +----------+ +----------+ +--------------+ +----------+
| | | | | | | +----------+ | | |
| | | | | | | | Packet | | | |
| | | | | | | | Network | | | |
| | | | | | | |(Vendor E)| | | |
| Radio | | Transport| | Mobile | | +----------+ | | Mobile |
| Access | | Network | | Edge DC | | * | | Core DC |
| Network |**| Domain 2 |**| Domain 3 |**| +----------+ |**| Domain 5 |
| Domain 1 | |(Vendor B)| |(Vendor C)| | | Optical | | |(Vendor F)|
|(Vendor A)| | | | | | | Transport| | | |
| | | | | | | | Network | | | |
| | | | | | | |(Vendor D)| | | |
| | | | | | | +----------+ | | |
| | | | | | | Domain 4 | | |
+----------+ +----------+ +----------+ +--------------+ +----------+
Figure 1: Multi-domains in Mobile Operator's Network
It consists of six domains:
1. Radio Access Network Domain
2. Mobile Backhaul Transport Network Domain
3. Mobile Edge Data Center Network Domain
4. Core Packet/Optical Transport Network Domain for Data Center
interconnect (this domain typically consists of multi-layer)
5. Mobile Core Data Center Network Domain
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6. Internet Core Network Domain
Mobile data application may find its servers hosted by the Mobile
Edge DC (Domain 3) while some other applications hosted by servers
in the Mobile Core DC (Domain 5). For the former case, the
connectivity starts from a RAN edge and terminates at a Mobile Edge
Data Center. For the latter case, the connectivity is extended
beyond the Mobile Edge Data Center and traverses the Mobile Backhaul
Transport Network domain and the Core Transport Network domain.
There are several issues that are relevant in the ACTN context:
1. Transport from RAN to Mobile Edge DC
From RAN to mobile edge DC, there is mobile backhaul transport
network that provides connectivity between a client data device and
one of the edge nodes in the Mobile Edge DC Domain. The backhaul
transport networks provide tunnels for data transport for mobile
applications. These tunnels are typically provisioned statically.
This mobile backhaul transport network can be a resource bottle
neck. Operators typically overprovision this backhaul network to
accommodate unpredicted serge of data traffic.
Resource abstraction is one of the missing operational mechanisms in
mobile backhaul network. Resource abstraction will give the current
network usage information to the operators and will help dynamic and
elastic applications be provisioned dynamically with QoS guarantee.
2. Transport from Mobile Edge DC to Mobile Core DC
From Mobile Edge DC domain to Mobile Core DC domain, there is core
transport network that provides connectivity between edges to core.
As Mobile Core DC servers may be geographically spread for load
balancing or for recovery, the selection of core DC location from
edge constitutes a data center selection problem.
To support dynamic and flexible connection setup for applications
that are of dynamic nature with flexible bandwidth, network resource
abstraction is needed to facilitate this operation.
3. Transport from Mobile Edge DC to Internet Core Network
From Mobile Edge DC domain to Internet Core Network, there is also
core transport network that provides connectivity between edges to
Internet core for Local traffic breakout (e.g. LIPA and SIPTO). As
Mobile Edge DC servers may be geographically spread at the network
edge side for load balancing, the selection of traffic from edge to
Internet core is required to be controlled. See [3GPP TR 23.859] for
related discussion.
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4. Multi-layer Integration/Coordination (aka., POI)
Within the core transport network domain, there is also a multi-
layer issue between packet networks and optical transport networks.
To support multi-layer routing and optimization, coordination
between these two layers are necessary. Network abstraction of both
packet and optical networks will be very useful to support different
applications flexibly and efficiently. See [ACTN-POI] for related
discussion.
5. End-to-end tunnel/transport operations/management from RAN to
Mobile Core DCN:
As there are multiple transport domains (namely, Mobile backhaul and
Core transport networks) involved for an end-to-end connectivity
within an operator's network, the coordination between these domains
are crucial for operation. Static provisioning with stitching
tunnels are inadequate for many applications/services requiring
strict QoS such as a guaranteed bandwidth and latency.
In the current network environments, these two domains are not well
coordinated due to various reasons including the lack of a global
resource view, a domain administrative boundary, and the differences
in transport technology and vendor equipment.
In summary, due to complexity in mobile operator's network in terms
of heterogeneous transport technology, organizational boundaries
between domains, multi-vendor issues and others, facilitating
connectivity that traverse the aforementioned multi-domains is not
readily achieved.
Each domain control establishing other domain control in a peer to
peer level creates permutation issues for the end-to-end control.
Besides, these domain controls are optimized for its local operation
and in most cases not suited for controlling the end-to-end
connectivity services.
Moreover, the path computation for any end-to-end connection would
need abstraction of network resources and ways to find an optimal
path that meets the connection's service requirements. This would
require knowledge of network abstraction and topology for all
domains through which a connection traverses.
For mobile networks, signaling is a complex issue as it involves not
only a session control but also a connection control. The
coordination between the session control and the connection control
has to be worked out for a seamless operation.
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From a network connectivity management perspective, it would require
a mechanism to disseminate any connectivity issues from the local
domain to the other domains whenever the local domain cannot resolve
a connectivity issues.
3. Virtual Network Operations for Mobile Operators' Networks
Based on the issues discussed in the previous section in regard to
the operations for mobile multi-domain networks, there is a need to
support a coordination that facilitates virtual network operation,
the creation of a virtualized environment allowing operators to view
the underlying radio access network, backhaul transport network,
mobile DC edge, mobile DC core, packet/optical transport network for
DC interconnect networks and their operation and management as a
single, virtualized network.
The basic premise of this virtual network operation is to create a
hierarchy of operations in which to separate virtual network
operations from physical network operations. This helps operators
build virtual network operations infrastructure on top of physical
network operations. Figure 2 shows a hierarchical structure of
operations.
+----------------------+
| MVNO Coordinator |
+----------------------+
|
| VNO-I
.------------------------------------------------------.
| | | | |
+----------+ +----------+ +----------+ +----------+ +---------+
| RAN | | Mobile | | Mobile | | Core | | Mobile |
| | | Backhaul | | Edge DCN | | TN | | Core DCN|
| Control | | Control | | Control | | Control | | Control |
+----------+ +----------+ +----------+ +----------+ +---------+
Figure 2. Mobile VN Operation Hierarchy
Figure 2 shows operations hierarchy based on Figure 1. The two main
ideas are:
1. Domain control/management entities (e.g., RAN Control, Mobile
Backhaul Network Control, Mobile Edge Data Center Network Control,
Core Transport Network Control, Mobile Core Data Center Network
Control) are kept intact to continue its domain operations with
its technology choice and policy, etc. As discussed before domain
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control/management entities can be a form of various types (e.g.,
SDN-controller, NMS/EMS, Control Plane, or a combination of these
entities, etc.) that is responsible for domain-specific network
operations.
2. The VNO Coordinator establishes a standard-based API (which is
termed as the Virtual Network Operations Interface (VNO-I) in
Figure 2) with each of the domain control/management entities. The
VNO coordination takes place via the VNO-I's.
4. References
[ACTN-Frame] D. Ceccarelli, L. Fang, Y. Lee and D. Lopez, "Framework
for Abstraction and Control of Transport Networks," draft-
ceccarelli-actn-framework, work in progress.
[ACTN-PS] Y. Lee, D. King, M. Boucadair, and R. Jing, "Problem
Statement for the Abstraction and Control of Transport
Networks," draft-leeking-actn-problem-statement, work in
progress.
[ACTN-POI] D. Dhody, et. al., "Packet Optical Integration (POI) Use
Cases for Abstraction and Control of Transport Networks
(ACTN)," draft-dhody-actn-poi-use-case, work in progress.
[3GPP TR 23.859] Local IP access (LIPA) mobility and Selected IP
Traffic Offload (SIPTO) at the local network.
5. Contributors
Author's Addresses
Jongyoon Shin
SK Telecom
6 Hwangsaeul-ro, 258 beon-gil, Bundang-gu, Seongnam-si,
Gyeonggi-do, 463-784, Republic of Korea
Email : jongyoon.shin@sk.com
Rod Hwang
SK Telecom
6 Hwangsaeul-ro, 258 beon-gil, Bundang-gu, Seongnam-si,
Gyeonggi-do, 463-784, Republic of Korea
Email : rod.hwang@sk.com
Jongmin Lee
SK Telecom
6 Hwangsaeul-ro, 258 beon-gil, Bundang-gu, Seongnam-si,
Gyeonggi-do, 463-784, Republic of Korea
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Email : jminlee@sk.com
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