Transcript PCECP Requirements and Protocol Extensions in Support of Global Concurrent Optimization

PCECP Requirements and
Protocol Extensions in Support of
Global Concurrent Optimization
<draft-lee-pce-global-concurrent-optimization-02.txt>
Young Lee (Huawei)
J-L Le Roux (France Telecom)
Daniel King (Aria Networks)
Eiji Oki (NTT)
68th IETF – Prague, Czech Republic
March 2007
Document Updates
• J-L Le Roux added to co-author list
• Global Concurrent Optimization (GCO) definition
included (per J. Ash)
• Requirements have been refined
– Clarifications in relation to RFC4657 (per J. Ash)
– New Requirements have been added
• PCEP Protocol Extension works included in the new
versions (01 and 02).
68th IETF – Prague, Czech Republic
March 2007
GCO Definition
Global Concurrent Optimization (GCO) is a concurrent path
computation application where a set of TE paths are computed
concurrently in order to efficiently utilize network resources.
A GCO path computation is able to simultaneously consider
the entire topology of the network and the complete set of
existing LSPs, and their respective constraints, and look to
optimize or re-optimize the entire network to satisfy all
constraints for all LSPs. A GCO path computation can also
provide an optimal way to migrate from an existing set of
LSPs to a reoptimized set (Morphing Problem).
68th IETF – Prague, Czech Republic
March 2007
Requirements Updates (Existing)
• GCO path computation indicator
• Global Objective Function (GOF)
– "synchronized objective functions" in section 5.1.7 [RFC4657].
– Three code points requested in the PCE OF Registry (defined in draftleroux-pce-of).
• Global Constraints (GC) field
– Max Link Util, Min Link Util, Max Hop, Exclusion of links/nodes
• Global Concurrent Vector (GCV) – use of SVEC object [PCEP]
• GCO related Error Indicators
• Multi-Session
– Indicator, session sequence number, final session indicator
68th IETF – Prague, Czech Republic
March 2007
Requirements Updates (New)
• Overbooking Factor added in the Global Constraint Field
(Ning So, Verizon)
• Disruption Minimization Mechanism in Bulk Reoptimization/Migration
– The Request for the Order in which LSPs should be re-optimized (i.e.,
migration path)
– In response to “ordering” request from the PCC, the PCE MUST
indicate the order in which LSPs should be re-optimized: setup order
and removal order
– Inclusion of the set of previously computed paths to avoid double
bandwidth accounting
– Make-before-Break indicator
68th IETF – Prague, Czech Republic
March 2007
PCEP Protocol Extensions
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GCO Indicator – a new flag (C flag) in the SVEC object
GOF (Global Objective Function) - three code points requested in the PCE OF
Registry
Request for the order of LSP to minimize disruption in case of bulk provisioning
– a new flag (D flag) in the RP object
Make-before-break Indicator – a new flag (M bit) in the RP object
The Order Response TLV defined in the RP object in the PCRep Message: Setup
Order and Delete Order
Global Constraints (GC) Object defined: MU, mU, OB, MH, XRO
Multi-Session (MS) Object is defined: F bit, M-Session ID, Sequence Number
Two new flags added to NO-PATH-VECTOR TLV in the NO-PATH object: 0x03:
no migration path found; 0x04: no feasible solution found
New Error-Type (14) and two new Error-values are defined to indicate errors
associated with GCO: memory overflow, GCO not capable
A new Error-Value (3) is defined in the existing Error-Type (5) to indicate “GCO
not allowed under policy.”
68th IETF – Prague, Czech Republic
March 2007
Summary & Next Steps
• GCO application is within Working Group charter.
– WG charter: Functional specification of MPLS and GMPLS Traffic
Engineered LSP path computation models involving Path Computation
Element(s). This includes the case of computing the paths of intra and
inter-domain TE LSPs. Such path computation includes the generation
of primary, protection and recovery paths, as well as computations for
(local/global) reoptimization and load balancing.
– RFC 4657 Section 5.1.17 – “Synchronized Objective Functions”
(Global objective); Section 5.1.7 – “correlated multiple requests”
• We have made significant progresses since 67th IETF
– Complete Set of Requirements
– Protocol Extensions in Good Progress
• Request to be accepted as WG draft when WG is ready
68th IETF – Prague, Czech Republic
March 2007