One document matched: draft-cheng-supa-ddc-use-cases-05.txt
Differences from draft-cheng-supa-ddc-use-cases-04.txt
Network Working Group Y. Cheng
Internet-Draft China Unicom
Intended status: Informational JF. Tremblay
Expires: August 10, 2015 Viagenie
J. Bi
Tsinghua University
February 6, 2015
Use Case for Distributed Data Center in SUPA
draft-cheng-supa-ddc-use-cases-05
Abstract
Large scale DCs can provide various services and usually have a lot
of internal and external links, and these links are usually VPNs.
The Service provisioning and network connectivity configurations are
complex and sometimes dynamic, for which manual configuration is not
suitable. This draft analyzes the use case in Distributed Data
Centers (DDC), in which some VPN scenarios are covered, and the
applicability of SUPA data models which can be used for better
resource usage and easy service/network configuration.
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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Drafts is at http://datatracker.ietf.org/drafts/current/.
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and may be updated, replaced, or obsoleted by other documents at any
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This Internet-Draft will expire on August 10, 2015.
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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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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Challenges Faced by Data Center ISPs . . . . . . . . . . . . . 4
5. SUPA Benefits . . . . . . . . . . . . . . . . . . . . . . . . 4
6. Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Scenario - Inter DC Connectivity . . . . . . . . . . . . . 6
6.2. Scenario - vDC Connectivity . . . . . . . . . . . . . . . 7
6.3. Scenario - Dynamic Link Configuration for DC . . . . . . . 8
6.4. Scenario - VPC to DC Connectivity . . . . . . . . . . . . 8
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
10.1. Normative References . . . . . . . . . . . . . . . . . . . 10
10.2. informative References . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10
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1. Introduction
The SUPA (Simplified Use of Policy Abstractions) work aims at
providing data models, including topology data models, network
service specific data models, policy data models, to easily,
accurately, and efficiently select and use the available
communication network capabilities. An example of the data model can
be found in [I-D.zaalouk-supa-configuration-model]. Service
Management (SM) is used by an a communications service provider
and/or operator to deploy and manage a communication network. An
example of SM is a set of applications used by an Operational Support
System (OSS) entity to perform network configuration. Several SUPA
use cases have been introduced in the problem statement document.
This document reviews various scenarios for Distributed Data Center
(DDC) use case.
Take a large-scale Internet Data Center (IDC) operator as an example,
it provides server hosting, leased line, value-added services to
enterprises and ISPs, and has more than 10 data centers using over
one Tbps of bandwidth in a capital city. In this IDC network,
traffic at each site is routed via configuring policy routes and
adjusting routes prioritization to choose an outgoing link. This
type of static provisioning comes with high costs and poor
operability. Furthermore, the link bandwidth resources in the data
centers are not efficiently utilized.
In quite some of the scenarios, the links between DCs are VPNs,
including L2VPN, L3VPN, etc. SUPA will be mainly used for those VPN
configurations. Althouth there may be some cases where physical
links are used, but those are out of the scope of this draft.
DC and network may belong to different operators. If a DC operator
needs to configure network connecivity for DCs, they may need to
coperate with network oprators. Network operators can define and
provide data models to enable this.
This document illustrates several distributed datacenter (DDC)
applications and explains how an operator could use SUPA to provide
these applications.
2. Requirements Language
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 [RFC2119].
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3. Terminology
The terminology used in the SUPA problem statement draft
[I-D.zhou-supa-framework] and
[I-D.karagiannis-supa-problem-statement] apply also to this draft.
DDC Distributed Data Center
IDC Internet Data Center
NM/NC Network Manager / Controller
SM Service Management
vDC virtual Data Center
VPC Virtual Private Cloud (PC)
4. Challenges Faced by Data Center ISPs
There are many challenges in traditional data centers: 1)
infrastructure and network link is usually leased, depending on
manual planning and design, which leads to low resource usage and
high cost; 2) Service expansion is limited in a single physical DC.
Each DC resource is isolated, so service and resource can only be
deployed in one single DC; 3) VAS (Value Added Service) is
provisioned via static configuration, which brings complex training,
long service TTM time and poor flexibility. This could not meet the
requirements of complex use cases, e.g., lot of VAS devices,
significant differences between various services.
5. SUPA Benefits
To solve the above challenges for data center ISPs, SUPA could be
applied in the following ways:
o SUPA supports an open network architecture: Open architecture,
unified architecture and unified planning, fast interconnection
with third party cloud platform, support fast service innovation.
o SUPA supports overall DC resource integration: Network resource
virtualization, inter-DC resource integration, virtual DC (vDC)
service provisioning, unified inter-DC service, which reduces
OPEX.
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o SUPA supports automatic E2E service delivery: Network (including
virtual network), computing, inter-DC management of storage
resource, automatic service delivery, which improves operation
efficiency.
o SUPA contributes to improve DDC network usage: Intelligent
scheduling of DDC traffic, improving link usage.
o SUPA supports VAS service on-demand provisioning automatically:
Create or delete VAS nodes on-demand, based on various service
requirements; network forwarding policy based on the VAS routing,
to achieve automatic draining and automatic configuration of VAS
device policy.
The following sections will illustrate three typical cases in
distributed data center which could benefit from SUPA architecture.
6. Scenarios
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6.1. Scenario - Inter DC Connectivity
+--------------------------+
| Service Management |
+--------------------------+
^
| Inter DC connectivity
| and policy
| data models
v
+--------------------------+
| Network |
| Manager / Controller |
+--------------------------+
/ \
/ \
+---------+ \
/| DC1 |\ \
/ +---------+ \ +-----------+
| | d1 \___a1________| DC-A |
| | | |
| +---------+ +-----------+
d3 | | DC2 |\
| +---------+ \ +-----------+
| | d2 \___a2________| DC-B |
| | ____a3________| |
\ +---------+ / +-----------+
\| DC3 |/
+---------+
Figure 1: Scenario - Inter DC Connectivity
There can be a lot of links between data centers. Configuration of
these links is complex. As shown in Figure 1, connectivity data
models and policy data models can be defined to automate the
configuration procedures. The service data model for connectivity
will specify attributes of links, e.g. the end points of links,
bandwidth and QoS, etc. The policy model can specify some high level
requirements to the links, like routing strategy and price/cost
stragety.
Inter DC connections can be classified into to types: connections
within a single administrative domain and connections across multiple
administrative domains. Links d1, d2 and d3 are within an
administrative domain; and links a1, a2 and 3 are across domains.
The difference between them is, connections across multiple
administrative domain require extra negotiation and authentication/
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authorization, which can be achieved via communications between MAs.
Data models for this purpose should also be defined.
6.2. Scenario - vDC Connectivity
+--------------------------+
| Service Management |
+--------------------------+
^
| vDC connectivity
| and policy
| data models
v
+--------------------------+
| Network |
| Manager / Controller |
+--------------------------+
/ \
/ \
/ \
+-------------------+ +-------------------+
| DC1 | | DC2 |
| +---------------+ | vDC link | +---------------+ |
| | Tenant1 (vDC) |<----------------->| Tenant1 (vDC) | |
| +---------------+ | | +---------------+ |
| | | |
| +---------------+ | | +---------------+ |
| | Tenantk (VDC) | | | | Tenantn (vDC) | |
| +---------------+ | | +---------------+ |
+-------------------+ +-------------------+
Figure 2: Scenario - vDC Connectivity
A DC tenant may have resources, e.g. network, computing, storage,
etc, in multiple physical DCs. DC operators will provide internal
network connections for these distributed resources, and make it look
like one seamless entity, which can be called as virtual DC (vDC).
The internal links for vDC can be implemented via tunneling
technologies, e.g. VPN or VxLAN, etc.
As show in Figure 2, connectivity data model and policy can be
defined to automate the links configuration for vDCs. A policy model
may contain information like user's grade which will be use to derive
service level parameters, including bandwidth, QoS, etc. The
connectivity data model may provide the information about the
resource location for tunnel setup.
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6.3. Scenario - Dynamic Link Configuration for DC
Static and over provisioning for DC links is not always a good
solution. Sometimes dynamic configuration is necessary.
One case is virtual machine migration and large amount of data
transfer between DCs. But this kind of activity does not happen
frequently. A dedicated link with constant bandwidth for this
purpose is too expensive. The network operator should allow the DC
operator to create a link on demand when necessary. This link may
have large bandwidth but last for a limit time period. An
alternative is to have a static link but with limited bandwidth; and
the bandwidth can be increased on demand for a short period.
Data models can help to automate these kind of configurations. These
data models will help DC operators to add and remove links, change
the attributes of links.
6.4. Scenario - VPC to DC Connectivity
+--------------------------+
| Service Management |
+--------------------------+
^
| VPC to DC connectivity
| and policy
| data models
v
+--------------------------+
| Network |
| Manager / Controller |______________
+--------------------------+ \
/ \ \
/ \ \
/ \ |
+-------------------+ +-------------------+ |
| Cloud for VPCs | | | |
| +---------------+ | VPC link | DC1 (Database) | |
| | VPC1 |-----------------| | |
| +---------------+ \ +-------------------+ |
| +---------------+ |\ |
| | VPC2 | | \ |
| +---------------+ | \ +-------------------+ |
| +---------------+ | \ VPC link | | /
| | ...... | | \__________| DC2 (Storage) |/
| +---------------+ | | |
+-------------------+ +-------------------+
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Figure 3: Scenario - VPC to DC Connectivity
As virtualization technology becomes more and more popular, some
organizations and companies now begin to use cloud platform to
support their computer desktop, rather than using physical personal
computers and workstations. The kind of cloud platform can be a
commercial solution, e.g. Amazon's cloud platform. VPCs at cloud
service providers' DC may keep on running for a long time even if no
user is actually accessing it; but the cloud platform may bring VPCs
into power saving mode when there is little or no load in it.
The organizations and companies, e.g. a university, sometimes provide
some internal services like database which is only available to the
VPC but not available to users in the public network. These kind of
services can be located in an cloud operator's DC.
The VPC and the internal services sometimes are located in different
DCs, or even provided by different vendors. VPNs are configured for
the VPCs to provide connection to the DCs where services are hosted.
As shown in Figure 3, connectivity data models and policy data models
can be defined to automate the configurations of links between VPC
and DC where service is located. In the data models, the location
where internal service is located should be specified; a user/VPC's
access rights can also be specified.
7. Security Considerations
Security is a key aspect of any protocol that allows state
installation and extracting of detailed configuration states. More
investigation remains to fully define the security requirements, such
as authorization and authentication levels.
8. IANA Considerations
Not applicable.
9. Acknowledgements
The authors of this draft would like to thank the following persons
for the provided valuable feedback: Cathy Zhou, Georgios Karagiannis,
Scott O. Bradner, James Huang.
10. References
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10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
10.2. informative References
[I-D.karagiannis-supa-problem-statement]
Karagiannis, G., Will, W., Tsou, T., Qiong, Q., Contreras,
L., and P. Yegani, "Problem Statement for Shared Unified
Policy Automation (SUPA)",
draft-karagiannis-supa-problem-statement-02 (work in
progress), October 2014.
[I-D.zaalouk-supa-configuration-model]
Zaalouk, A., Pentikousis, K., and W. Will, "YANG Data
Model for Configuration of Shared Unified Policy
Automation (SUPA)",
draft-zaalouk-supa-configuration-model-01 (work in
progress), October 2014.
[I-D.zhou-supa-framework]
Zhou, C., Contreras, L., Qiong, Q., and P. Yegani, "The
Framework of Shared Unified Policy Automation (SUPA)",
draft-zhou-supa-framework-00 (work in progress),
January 2015.
Authors' Addresses
Ying Cheng
China Unicom
P.R. China
Email: chengying10@chinaunicom.cn
JF Tremblay
Viagenie
Email: jean-francois.tremblay@viagenie.ca
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Jun Bi
Tsinghua University
Bei Jing
China
Email: junbi@cernet.edu.cn
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