Transcript Document

ASTN/ASON and GMPLS
Overview and Comparison
By,
Kishore Kasi Udayashankar
Kaveriappa Muddiyada K
1
Motivations
 Complex process of provisioning of end-to-end transport
service
 Heterogeneous transport networks
 Automation of end-to-end provisioning
 Ability to offer more service
 Directly integrate IP clients over WDM
 How?
 “intelligence” into the control plane of OTN
 automatic and seamless circuit provisioning
 unified control binding technologies
 Benefits?
 cost reduction and better quality of network operation
 simplified and rapid network configuration
 switched services and dynamic bandwidth assignment
ASTN/ASON
 ITU-T Recommendation G.805/G.8080
 Architecture that defines the components and interactions
between components
 Distributed control plane
 Task of control planes
 Call and connection control
 Path control based on network state
 Discovery for self configuration
ASTN/ASON (Continued…)
Protocols must support multi-layer, multi-vendor network
 Layering
 Administrative partitioning
 Operational partitioning
 Types of interfaces in the
control plane
GMPLS
Unified control plane for packet and circuit switching
technologies
 Four interfaces.
 Interface Switching Capability
 No NNIs.
GMPLS (Continued…)
 Extension of routing protocols
 OSPF-TE and ISIS-TE
 Signaling protocols, RSVP-TE and CR-LDP
 Label Switched Paths (LSP)
Multi-layer Resource Model Representation
In GMPLS
 Basic topology abstraction is TE link
 Link interface can support one or more interface switching
types defined
 Interface Switching Capability (ISC)
 ISC descriptor describes related TE properties
 A particular resource on a link is represented by a label
In GMPLS (Continued...)
 Basic service abstraction is a LSP
Concept of hierarchical LSP
 LSP in server region represented as TE link or
Forwarding adjacency in client region
 Client LSP routed over a TE link == tunneled within a
server LSP
Multi-layer Resource Model Representation
In ASON
 ISC concept has been reduced
 Optical part of OTN hierarchy is mapped to LSC
 Digital path layers of OTN and SDH hierarchy is mapped to
TDM
In ASON (Continued…)
In ASON (Continued…)
Transport
networks functional
model G.805
 Client/server
association between
adjacent layers
 Each layer
partitioned to reflect
internal structure
In ASON (Continued…)
 Partitioning concepts
 Starting from the smallest indivisible subnetwork
 Contained and containing subnetwork
 Contained subnetwork cannot provide connectivity not
available in containing subnetwork
 Ports on boundary of containing subnetworks and
interconnection capability are represented by contained
subnetworks
In ASON (Continued…)
 Partitioning concepts (contd…)
In ASON (Continued…)
 Layering concepts
 Layer networks in a client-server model
 Termination and Adaptation Functions
 Topology and connectivity not visible to client
In ASON (Continued…)
Overview of MPLS/GMPLS Concepts
 Forward Equivalence Class
 Label
 LSR
 LSP
Label allocation
 Next Hop Label Forwarding Entry (NHLFE)
 Route selection
From: Dr. Harry Perros, Connection Oriented Networks (CSC 576), Fall ‘06
From: Dr. Harry Perros, Connection Oriented Networks (CSC 576), Fall ‘06
Control Plane Architecture
In GMPLS
 Peer model
 Overlay model
Augmented model
Control Plane Architecture
In ASON
Protocol neutral way
 Support various transport infrastructure
 Applicable irrespective of control plane that has been
subdivided into domains
In ASON (Continued…)
 General model of policy
 System is a collection of
components
 System boundary
 Nested system
boundaries
 Policy port as filters
In ASON (Continued…)
 General model of federation
 Creation, deletion and maintenance of connections
across multiple domains
 Community of domains
 Domains cooperate for connection management
 Joint Federation Model and Cooperative model
In ASON (Continued…)
Joint federation Model
Cooperative Model
In ASON (Continued…)
 Architectural components
 Connection controller (CC) component
 Routing controller (RC) component
 Link resource manager component
 Traffic policing (TP) component
 Call controller component
 Discovery agent (DA)
GMPLS Control Plane, Policy-based
Management and Information Modeling
 Policy based Management (PBM)
 Improve collaboration between management and
GMPLS control plane.
 Extending Policy Core Information models (PCIM) with
policy events.
 Diverse local and global decision logic distributed
among multiple network elements and network layers.
Discussion Items
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Advantages and Features.
Types of GMPLS policies and actions – few examples
Control plane and PBM architecture.
GMPLS managed entities
Two uses cases to explain PBM in GMPLS
Advantages
 Dynamic, flexible and cooperative interworking
 Traffic engineering (TE) capabilities brought by
GMPLS.
 Improve operational efficiency.
 New services requires complex and dynamic
configurations of network resources.
 Avoid configuring node-by-node and consider entire
network domain as a whole.
 Increase automation by using rule sets.
Features
 Standardized operational processes in multi-vendor
environments.
 Policy rule - Network operator has control over state
changes for a given network function.
 Adapting and changing behavior at runtime.
 Translating SLA, network and management areas (eg.
Routing, configuration, fault management) into
policies.
 Adding/deleting/modifying policies in policy
repository.
Features (Continued…)
 PBM Framework
 Policy based admission control.
 Policy Information Models
 “Policies are used to control the
state that a managed object is in at
any given time; the state itself is
modeled using an information
model”.
 Policy core Information Model
(PCIM), MIB, PIB.
 Policy rule – It is a binding of a
set of policy actions to a set of
policy conditions.
Policies and Policy Actions
 Admission Control Policy
 Call/connection admission action, Call/connection Rejection Action.
 Signaling Control Policy
 Signaling recovery action
 TE Routing Policy
 Link State Advertisement action, Manage TE Info action
 Path Computation and Selection Policy
 Path computation action, Link Type selection action
 Load Distribution Policy
 Load distribution action
 Recovery related policies……
Control Plane and PBM Architecture
 Need for a separate Control Plane
(CP)
 Fundamental principles of
GMPLS CP
 Separating protocol generic and
application specific mechanisms.
 TE Link as a unique application
specific entity.
 Two-stage OSPF architecture and
database.
 TE Link – resource aggregates
that are encoded as links with TE
attributes.
 OSPF-TE with opaque LSA
capabilities along with topology
LSA distribution.
GMPLS Managed Entities
 Features of NOBEL Information Model.
 Specifies managed entities and represents control plane (CP)
 Components, capabilities, interworking of CP components.
 CP Element represents a control plane instance hosted
by a CP node.
 Separate instances of managed entities for control plane
and transport plane entities.
Managed entities representing CP Elements
and components
Use Case 1
 Combined call and connection setup via User Network
Interface (UNI).
 Considering circuit switch capable GMPLS network.
 SLA/SLS information installed in policy and service admission
repository.
 Global call admission directives in global Call admission policy
decision point (PDP) downloaded by policy execution point (PEP).
 Local and node specific connection admission policies in global
connection admission PDP.
Call and Connection Setup via UNI
Description
[1] connection request using call setup messages over UNI
[1b] comparing client id and port with call admission
directives, does not match.
[2a] call level parameters translate into network resource
related requirements and evaluated by LPDP.
[2b] requirements verified against general connection
admission policy
[3] May be asked to renegotiate due to network or node
limitation
Continued…
[4] connection setup is delegated to TEC which checks
against path selection policy rules with LPDP
[5] signaling controller (SgC) requests LPDP to check
against signaling control policy rules.
[6] ingress node signals modified call setup request.
Use Case 2
 Event Driven TE Policy action for TE link utilization
threshold crossing event.
 Emits threshold crossing alert (TSA).
 use case example - Predefined percentage (say 85%) of the
current forwarding adjacency (FA) packet switched connection
(PSC) link unreserved bandwidth is consumed.
 TE link utilization thresholds are set.
 TE Control action –
 New FA PSC LSP
 New FA TDM LSP eg. At the server layer.
Event Driven TE Policy Action
Description
[1a] TE link emits TCA to TEC, internal signal.
[1b] TE link emits TCA to Management Plane (MP), CPMP interaction notification.
[2] TEC requests PEP to invoke event policy rule.
[3] PEP forwards decision request to PDP (local, global or
both)
[3a],[3b] LPDP evaluates load-distribution action policy
rule. If it does not succeed, create LSP create action
policy is evaluated with global PDP.
Continued…
[4] LPDP evaluates path computation/selection policy
rules and delegates TEC to enforce policy decisions.
[5] TEC triggers SgC for setup of server layer.
[6] If success, TEC will check LSA update policy and
Information dissemination policy to initiate LSA
update.
[7]. TEC updated TEDB with new FA-LSP and notifies MP
about result of policy decision [8a]
[8b] TE Link emits state change notification to inform MP.
Bibliography
• G.805 ITU-T specification
• G.8080 ITU-T specification
• ASON Current status of standardization work, B.
Zeuner, G. Lehr, Deutsche Telekom
• ASON and GMPLS – The battle of optical control plane
– Data connection limited.
• Control plane for Optical networks: The ASON
Approach, Andrzej Jajszczyk, AGH University of
science and technology, Krakow, Poland
• ASON and GMPLS – Overview and Comparision, S.
Tomic, B. Statovci-Halimi, A. Halimi
• GMPLS Control Plane, policy based management, and
information Modelling, H.Lonsethagen, et. al.