GNA – Global Network Architecture
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Describing A Reference Architecture for a Global R&E
Network
Dale Finkelson
GNA Technical Group
26 October 2015
0.9P
Describing A Reference Architecture
for a
Global R&E Network
1. Introduction
In 2013, the members of the Global R&E Network CEO Forum embarked on a project
to define a reference architecture for an intercontinental R&E Networking. The aim
of this project is to define a blueprint that R&E Networks and funding agencies
around the globe can use to align their investments in intercontinental circuits to
serve Research & Education, with the goal of coming to a more consistent and
effective high-performance global network for R&E.
In order to create this reference architecture it is important to understand what the
components of this Architecture, called the GNA (Global Network Architecture), will
be and how they will be described. The purpose of this document is to provide
guidance for people new to the GNA activity, as well as provide an overview of the
components of that work.
2. A Global Network Architecture
To fully develop the Global Network Architecture it is important to look at what is
meant by “Architecture” in this context. Equally it is important to understand and
explain what it takes to be an “effective” architecture.
Fundamental to this discussion is the understanding that the GNA is not a network;
it is rather a reference architecture or a blueprint that can be used by organizations
or consortia that are investing in global infrastructure to determine if that
infrastructure is consistent with the view of global connectivity that the
Architecture defines.
At one, fairly straightforward level, the Global Network Architecture is described as
a set of transoceanic circuits that are terminated at Open Exchange Points where
participant networks interconnect. For this to be an effective infrastructure there
would need to be sufficient interconnects to ensure resilient, physically redundant
and operationally stable facilities.
Were it the case that one organization was building, configuring and operating a
global network infrastructure that any R&E Network or R&E organization could
participate in the above description would be sufficient. Instantiating the network
would be a simple matter of procuring sufficient circuits and building adequate
exchange points. But of course this is not how this activity will progress, as the set of
R&E Networks around the globe are not organized, funded or operated in this
manner.
No single organization will have the resources to create this network. It will rather
be a series of cooperative efforts between national and regional R&E Networks
working to build a shared infrastructure that serves their needs as well as making
resources available to other organizations.
3. Ingredients of a GNA
What is meant by “creating a Global Network Architecture“ in this instance is not
this unified traditional approach where the main issues are physical design and cost.
Rather this activity should be thought of as creating a blueprint that lays out the
principles of an effective and useful global infrastructure built and used by multiple
organizations around the globe. As individual components of this infrastructure are
brought into service by R&E Networks, the degree to which those links are a useful
part of the global infrastructure can be determined by how closely they conform to
the blueprint. Rather then a unified network design, the GNA is a multi-faceted
design.
The architecture consists of two related but separate components, a Governance
and Policy (GP) component and a Technical and Operations (TO) component. A
description of the architecture elements in these components follows, along with a
short description of the individual elements.


Governance and policy:
o Governance
o Policy
o AUP
o Economics & cost sharing
o Changing dynamics of circuit costs
o Higher bandwidth (upgrades) and new technologies
o Changing realities of where R&E needs to connect to do its work
o Data Privacy
Technical and Operations:

o Federated operations models
o Network services beyond best effort IP
o Production quality Open Exchange Points able to meet the service
requirements of its participants.
Both GP and TO.
o Location of Content required by the participants
o End-to-end SLAs
o The Commons
3.1 Governance and Policy Components:
The blueprint describes a shared, cooperative activity. As such it is important that
there be adequate governance models for each component and that there be a
methodology for interaction between the governance groups in the overall
infrastructure.
3.2 Policy Considerations in Exchange Points
A critical feature of the participating Exchange Points is that they be open and policy
free. They should not impose restrictions on who is allowed access (assuming fair
and appropriate payments) or who in entitled to establish services with whom. This
does not imply that every organization must talk with every other participant, only
that the Open Exchange Points cannot impose restrictions. More detail on the
Exchanges is documented in a separate paper.
3.3 AUP
The network links and Exchange points that conform to this blueprint have an Open
Acceptable Use Policy (AUP) themselves. All internal or accepted traffic is governed
by the AUPs of the participating organizations.
The Open Exchange Points in use by the network built against this blueprint as well
as the links comprising the networks built against the GNA cannot restrict which
types of traffic are allowed to flow/transit or otherwise limit their use in any way.
Many of the R&E service requirements depend critically on access to services
provided by the commercial Internet, or through dedicated paths to these service
providers. This would include cloud services for both storage and compute. All
traffic that is originating or terminating inside a participant of the GNA will be
eligible to traverse these networks in order to access to such services should that be
necessary.
This of course does not imply that individual organizations cannot have or impose
AUP restrictions within their networks. They are of course free to restrict internal
connections and traffic, as they need.
3.4 End-to-end SLAs
The ability to deliver end-to-end SLAs is critical to the success of the participating
R&E Networks. The goal is seamless service delivery whether it is local or global.
Along with specifying the characteristics of the services delivered, other parameters
within the SLA should be specified. Among these would be:
- Delivery time of a new service
- Time it takes to get feedback on the time needed to set up the service
- Cost to turn up a new service.
A goal of the global activity is for a participating organization to be able to deliver
any service to its users any place and any time with as close to the same
characteristics as local delivery of that service. Some differences may be
unavoidable, for instance latency.
3.5 Economics & cost sharing
By combining and aligning investments of the leading R&E Networks across the
globe we create a more powerful and future proof set of interconnects between
national, regional and international efforts, for the benefit of Research & Education.
3.6 Dynamics of Circuit Costs
Increasingly users require the ability to move flows of greater then 10G; doing so is
frequently achieved through the purchase of 100G circuits. While the costs of 100G
have dropped to between 3-7 times the costs of 10G, they are still fairly expensive.
Sharing these costs is important to being able to implement the level of connectivity
that R&E needs. This trend is expected to continue when we move to speeds beyond
100G, i.e. to 400G, 1T and eventually spectrum.
Also as these costs drop over time building more diverse infrastructures will
become both possible and desirable.
It is also expected there will be another significant step up in bandwidth
requirements, as flows of well over 10G become the norm. This growth will be seen
especially in the big sciences and in cloud access.
3.7 Content
Some version of content management may well enter into this activity. As campus
activities become increasingly global the idea that the best place to locate content is
at the local, regional or national university's machine room will diminish. It will
become increasingly important to locate content in neutral locations much closer to
the consumers of the content. This will require global structures for storing and
managing content. While the GNA working groups will not be directly dealing with
this, work on storage and computing might spin of from this activity.
3.8 Changing realities of where R&E needs to connect to do its work
Given the changes in student populations, the increasing globalization of science
instruments, and the demand for online learning from all locations and the desire to
partner across borders and on a global scale, having a comprehensive global
connectivity strategy is required for campuses and researchers across the globe.
Having connectivity meeting the requirements of this reference architecture will
allow that strategy to develop.
3.9 Data Privacy
All participating organization must have well established and documented policies
on the collection and distribution of traffic data for everything that traverses their
portion of the infrastructure. It is highly encouraged that these policies can be found
online. More detail on privacy considerations can be found in a separate document.
4.0 Technical and Operational Components
There are also significant Technical and Operational elements to consider in this
architecture. The aim is to enable the participants to achieve the service delivery
models they require and to maintain a stable and secure infrastructure. Technical
and Operational elements are described in a separate document.
4.1 Network services beyond best effort IP
The requirements dictated by the financial models for quality of service and other
circuit based connectivity models will continue to drive the need to move beyond
best effort IP. Best effort IP will still be needed, but for much of the other
connectivity needed that model will not be adequate, hence the strive to define
dedicated deterministic services and other service types.
4.2 Federated operation models
The multi-tenant, multi-vendor, multi-participant models being employed dictate
new and differing operational models.
Since this will be a co-operative effort among disparate groups, some of whom may
well not have direct access to the equipment that lands these circuits, different
models are being developed to support this architecture. In particular a Federated
Operations model is being created that addresses the known issues. The details of
that model are being documented in other papers, and are being tested in GNA
Pathfinders.
4.3 Production Quality Open Exchange Points
For this architecture to work there must exist Open Exchange Points. These facilities
must be able to deliver desired services to the organizations participating in the
Exchange Point. These service requirements will frequently extend beyond the
traditional Layer 2 interconnect service.
The details of what the requirements and expectations around these exchange
points are provided in another document.
4.4 The Commons
A critical piece of this architecture is providing a common space that is available to
the community at large, independent of their participation in obtaining circuit
capacity. These common facilities are also available to the collaboration (whatever
that may be for a given link) for bursting. The Commons would in general be best
effort IP, though layer 2 would also be an option.
It is the provisioning of the Commons that to a great extent distinguishes this effort
from the past effort of R&E Networks in creating global connectivity. Providing this
space allows for the growth of the R&E community by allowing the sort of global
connectivity that many small and developing R&E Networks would never otherwise
be able to manage.
Understanding the Commons and how it is used as well as the potential abuse of it
and how that needs to be dealt with will need to be explored in much greater depth,
and is dealt with in another document.
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