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Hybrid networks are intended to provide
a flexible mix of IP routed service and dedicated capacity ÒcircuitsÓ |
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The ÒMulti-LayerÓ is meant to identify
several items regarding how hybrid networks may be built. In this context it includes the
following: |
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Multi-Technology - MPLS, Ethernet,
Ethernet PBB-TE, SONET, NG-SONET, T-MPLS, WDM |
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Multi-Level - domains or network
regions may operate in different routing areas/regions, and maybe be
presented in an abstracted manner across area/region boundaries |
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Multi-Domain indicates that we want to
allow hybrid network service instantiation across multiple domains |
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And of course all this implies that
this will be a Multi-Vendor environment. |
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Currently an early deployment of a
Hybrid Network Control plane on ESnet SDN and Internet2 DCN |
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and some regional's such as DRAGON,
NYSERNet, others |
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This evolved out of collaborations
between several projects including ESNet OSCARS, I2 BRUW, NSF DRAGON, and the
DICE Group |
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It is expected that this will evolve as
standards bodies and other groups work on developing interface
specifications/agreements with the larger community |
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Key features of the current
architecture are noted in the following bullets. |
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One InterDomain Controller (IDC) per
domain which is responsible for inter-domain messaging |
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A ÒDomain ControllerÓ (DC) which takes
care of provisioning inside the domain. |
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The DC is really an internal domain
concern |
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The DC design will vary by domain
(based on technology types, vendor capabilities, etc), and in some instances
may be a very minimal set of functions |
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The IDC/DC combination provides the
basis for a two-level hierarchical network view. Where the DC will have knowledge of the real local
topology and the IDC may have a reduced or abstracted view. |
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Four distinct phases are identified for
IDC communications: User Request, Topology Exchange, Resource Scheduling,
Signaling |
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Topology Exchange: currently based on
abstracted link states, with little to no dynamic information. |
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We are also planning to investigate use
of a path vector style of inter-domain information exchange. |
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Resource Scheduling: multi-domain,
multi-stage path computation process where the specific resources get
identified and reserved for a specific signaling event. |
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The Signaling Phase is where specific
network elements are provisioned.
This phase may be initiated by the user, or by the domains. The Signaling Phase actions are based
on resources identified in the Resource Scheduling phase. |
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User Request Phase provides a message set for users to request
multi-domain circuits |
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Current security and authentication
models are based on signed soap messages and X509 Certificates (User to local
IDC messaging; IDC to IDC messaging) |
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Enhanced Circuit Parameters and User
Request Mechanisms |
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Richer set of flexible circuit request
constraints such as technology type, flexible time period specifications,
latency, jitter, adjustments to in-service circuits, arbitrary business
/administrative/security constraints, flexible user requests mechanisms. |
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Topology Building: combining multiple
individual circuits together into a user specified topology. |
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Network Virtualization - True
Multi-Level, Multi-Technology, Multi-Vendor network control and provisioning |
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Only talking about network resources
here; correlation with application domain resources is considered a separate
activity. |
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A key requirement for the architecture
is to be able to handle the reality that the underlying networks will be very
heterogeneous in terms of technology, control mechanisms, and vendors. |
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In the current architecture this is
abstracted out by the DC to IDC interface. |
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Four types of underlying domain types
have been identified in terms of how the DC interacts with them: |
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GMPLS (I2 DCN is an example, regional
networks based on ethernet switch dynamic provisioning is another example) |
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MPLS (ESNet SDN is an example) |
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Management Plane Controlled (USN is an
example) |
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Vendor Control Plane (I2 DCN also has a
component of this) |
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IntraDomain provisioning requires a
path computation process to determine a path across the local network |
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If the domain consists of multiple
technologies, multiple levels, and multiple vendors this problem can be
complex |
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In order to realize the advanced
control plane features multi-domain path computation needs to be augmented to
operate in these environments.
This will likely include addition of the following constraints to the
path computation process: |
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time domain |
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flexible set of AAA and other user
defined constraints |
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Ability to look for paths as a group in
the context of a entire topology build. |
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These scheduling and flexible policy
processing mechanisms will need to be tightly integrated/coupled with path
computation and selection processes |