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Use of Overbooking in Diffserv-aware MPLS Traffic Engineering <draft-wlai-tewg-overbook-00.txt> IETF’57 TEWG Meeting Vienna, July 14, 2003 Jerry Ash, Wai Sum Lai AT&T Labs. Overbooking in DS-TE Per-domain per-CT overbooking Specified in current PROTO, MAM, and RDM drafts
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Use of Overbooking in Diffserv-aware MPLS Traffic Engineering <draft-wlai-tewg-overbook-00.txt> IETF’57 TEWG Meeting Vienna, July 14, 2003 Jerry Ash, Wai Sum Lai AT&T Labs
Overbooking in DS-TE • Per-domain per-CT overbooking • Specified in current PROTO, MAM, and RDM drafts • Based on existing techniques for aggregate TE: Link size overbooking LSP size overbooking • Per-link per-CT overbooking • Addressed by this draft • Two methods compared: Components-based approach (based on the LOM) Integrated approach
Components-Based Approach (the LOM Method) New concepts • LOM = local overbooking multiplier • Normalized bandwidth = reserved bandwidth / LOM Bandwidth Constraints • Unaffected by LOM Unreserved Bandwidth • Needs to be adjusted to account for LOM Maximum Reservable Bandwidth • Relationship with LOM currently unspecified Impact on operations • Different formulas for different overbooking scenarios
Integrated Approach Single concept, single formula • Maximum reservable bandwidth = maximum link bandwidth • OB = overbooking factor • OB = LSOM * LSPOM * LOM LSOM = link size overbooking multiplier LSPOM = LSP size overbooking multiplier LOM = local overbooking multiplier Impact on router operations • Reserved bandwidth = Tspec / OB
Integrated Approach Issues under discussion • router interpretation of Tspec to determine ‘reserved bandwidth’ • relationship to current overbooking models • validity of Maximum reservable bandwidth = maximum link bandwidth