Bandwidth Constraints Models for Diffserv-aware

1

• Bandwidth Constraints Models for Diffserv-aware
• MPLS TE Performance Evaluation
• ltdraft-wlai-tewg-bcmodel-02.txtgt
• IETF57 TEWG Meeting
• Vienna, July 14, 2003
• Wai Sum Lai
• ATT Labs
• wlai_at_att.com

2

• Whats changed
• More explanatory text
• LSP blocking/preemption and Diffserv QoS
  degradation
• BC model design considerations
• New results
• Performance under partial preemption
• Performance under blocking

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• Operational Characteristics
• General trade-off
• bandwidth sharing to achieve greater efficiency
  under normal conditions
• robust class protection/isolation under overload
• Russian Dolls Model
• higher degree of sharing allowed
• leads to its inability to offer robust class
  isolation under overload conditions
• Maximum Allocation Model
• each class has its own bandwidth access limits
• leads to reduced degree of interference among the
  different classes

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• Performance Comparison
• Russian Dolls Model
• allows greater sharing of bandwidth among
  different classes
• performs somewhat better under normal conditions
• works well when preemption is fully enabled
• under partial preemption, not all preemption
  modes work equally well
• Maximum Allocation Model
• does not depend on the use of preemption
• is relatively insensitive to the different
  preemption modes when preemption is used
• provides more robust class isolation under
  overload

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• Next Step
• As agreed in the last meeting, to submit as an
  individual submission, with review by the TEWG