Ason Gmpls
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Transcript of Ason Gmpls
1
ASTN/ASON and GMPLS Overview and Comparison
By,
Kishore Kasi Udayashankar
Kaveriappa Muddiyada K
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
GMPLSUnified 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
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), CP-MP 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.