Constraint-based LSP Setup using LDP

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Constraint-based LSP Setup using LDP

• Bilel Jamoussi
• jamoussi_at_nortelnetworks.com

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Agenda

• Overview MPLS Values
• Traffic Engineering Requirements
• Constraint-based LSP setup using LDP
• CRLSP Setup
• Progress in IETF Consensus
• Progress in IETF Running Code
• Issues with RSVP Extensions
• Questions to ISPs

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Overview MPLS Values

• Traffic Engineering
• IP-VPN
• L2/L3 Integration

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Traffic Engineering

• Requirements for Traffic Engineering Over MPLS,
  D. Awduche, et al
• Strict Loose ER
• Specification of QoS
• Specification of Traffic Parameters
• Route Pinning
• Preemption
• Failure Recovery
• Recently, MPLS-OMP, C. Villamizar

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Constraint-based LSP Setup using LDP

• Uses LDP Messages TLVs
• LDP runs on a reliable transport (TCP)
• Does NOT require hop-by-hop
• Introduces new TLVs to signal ER, and other
  Constraints
• QoS,
• Traffic Parameters,
• Preemption,
• Route Pinning
• TLVs for Error handling diagnostics

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CRLSP Setup
IN LER
1 LSR
2 LSR
3 LSR
Out LER
Notification
Release / Withdraw
Downstream on demand ordered label distribution
mode
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Current CRLDP QoS Support

• Three Service Class
• Best Effort
• Throughput Sensitive
• Delay Sensitive
• Traffic Parameters
• Peak Data Rate
• Committed Data Rate
• Committed Burst Tolerance

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Progress in IETF Consensus

• Constraint-Based LSP Setup using LDP
• 14 vendors ISPs collaborated on CRLDP
• Accepted through MPLS WG Consensus
• CRLDP is included by reference in the base LDP
  Specification
• LDP Spec is going thorough last call this month

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Progress in IETF Running Code

• Constraint-Based LSP Setup using LDP
• Demonstrated interoperability among 3 Vendors
  implementations in November 98
• CRLDP is simple, stable, robust, and easily
  extendible
• Implementations are being tested

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Issues with RSVP Extensions for MPLS

• Soft state refresh overhead is problematic for
  MPLS scalability
• Latency reliability problematic for robustness
• Fundamental changes to the RSVP protocol are
  proposed
• RSVP WG expressed resistance to extensions in
  Orlando IETF
• Discussion has not yet started on RSVP mailing
  list

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Questions to ISPs

• Is MPLS viewed as mainly an Intra-Provider
  solution in the short-term?
• If so, is QoS is a requirement?
• Is MPLS a viable Inter-Provider solution?
• Will ISPs offer MPLS as a service?
• Is Loose Explicit Routing a requirement?