67th IETF - San Diego, CA, USA
November 8, 2006
PCECP Requirements for support of GlobalConcurrent Optimization
<draft-lee-pce-global-concurrent-optimization>
Y. Lee, Huawei, D. King, Aria Networks, E. Oki, NTT
67th IETF - San Diego, CA, USA
November 8, 2006
What is Global Concurrent Optimization?
An application of path computation in which we computea large number of TE-paths concurrently to meet aglobal objective by looking at the entire set of networkresources and topology.
67th IETF - San Diego, CA, USA
November 8, 2006
Motivation
•Sequential path computation may result in sub-optimaluse of network resources in some applications.
•Efficient utilization of network resources from a globalnetwork perspective that would to translate operationscost saving
•For example, full network re-optimization
•A PCE supporting concurrent path computation wouldhave the ability to consider global network capacitiesand properties, all service requirements and constraints,and then optimally place all services to meet the servicerequirements within the confines of the networkinfrastructure.
67th IETF - San Diego, CA, USA
November 8, 2006
A simple path computation trap problem
Consider a simple network topology
• All links are 5Mbps
• Various link costs
Node 1
Node 2
Node 3
Node 4
Node 5
Node 6
Cost
1
Cost
1
Cost
1
Cost
10
Cost
10
Cost
10
Cost
10
1.Request two least cost paths form Node-1to Node-4 with bandwidth 3Mbps.
2.Sequential computation places first LSPon the path 1-2-3-4.Second LSP cannot be placed.
3.Parallel computation can place both LSPsas 1-5-3-4 and 1-2-6-4.
Many more LSPs, many ingresses and egresses, and a more complex networkmake the problem much harder.
67th IETF - San Diego, CA, USA
November 8, 2006
Application Scenarios
•Greenfield Traffic Engineering
•Re-optimization of Existing Networks
–Traffic Migration
–Catastrophic Failure
•Pre-establishment of the H-LSP in Multi-Layer TrafficEngineering
•Reconfiguration of the VNT
67th IETF - San Diego, CA, USA
November 8, 2006
PCE-based Architecture for PCE GlobalConcurrent Optimization Application
PCE
TED
Head End
Nodes
Adjacent
Nodes
NMS
application
request
PCECP
request/
response
service
requests
Reference: RFC4655 Section 5.5 – Management-Based PCE Usage
67th IETF - San Diego, CA, USA
November 8, 2006
Application-SpecificProtocol Requirements
•Indicator field for global concurrent optimization
•Global objective function field
•Global constraints field
•Global concurrent vector field
•Indicator for failure of global concurrent optimization
•Multi-session indicator
•List of existing LSP to be kept intact
•More to be identified
67th IETF - San Diego, CA, USA
November 8, 2006
Summary & Next Step
•This I-D provides application-specific PCECPrequirements for support of global concurrentoptimization
•This I-D supplements the PCECP generic requirements[RFC4657] and is compliant to PCE-based architecture[RFC4655]
•To be considered as WG document
•Solicit complete set of requirements
•Begin protocol work for this application upon consensus