Hi WG, Here is the update to the I.D. with the correction made to Link Reserved Bandwidth Utilization (LRBU) calculation and its respective objective function Maximum Reserved Under-Utilized Path (MRUP).
Regards, Dhruv A new version of I-D, draft-wu-pce-pcep-link-bw-utilization-02.txt > has been successfully submitted by Dhruv Dhody and posted to the > IETF repository. > Name: draft-wu-pce-pcep-link-bw-utilization > Revision: 02 > Title: Extensions to Path Computation Element Communication > Protocol (PCEP) for handling Link Bandwidth Utilization > Document date: 2014-02-07 > Group: Individual Submission > Pages: 15 > URL: http://www.ietf.org/internet- > drafts/draft-wu-pce-pcep-link-bw-utilization-02.txt > Status: https://datatracker.ietf.org/ > doc/draft-wu-pce-pcep-link-bw-utilization/ > Htmlized: http://tools.ietf.org/html/ > draft-wu-pce-pcep-link-bw-utilization-02 > Diff: http://www.ietf.org/rfcdiff? > url2=draft-wu-pce-pcep-link-bw-utilization-02 > Abstract: > The Path Computation Element Communication Protocol (PCEP) provides > mechanisms for Path Computation Elements (PCEs) to perform path > computations in response to Path Computation Clients (PCCs) requests. > Link bandwidth utilization considering the total bandwidth of a link > in current use for the forwarding is an important factor to consider > during path computation. This document describes extensions to PCEP > to consider them as new constraints during path computation. > > > > Please note that it may take a couple of minutes from the time of > submission > until the htmlized version and diff are available at tools.ietf.org. > The IETF Secretariat On Fri, Jan 24, 2014 at 6:29 PM, Dhruv Dhody <[email protected]> wrote: > Hi PCErs, > > Authors have received a following suggestion to change the description for > the new objective function > Maximum Reserved Under-Utilized Path (MRUP) [ > http://tools.ietf.org/html/draft-wu-pce-pcep-link-bw-utilization-01#section-6.2 > ]. > > We agree that the use of Maximum reservable bandwidth R(L) would be the > correct way. We plan to make this change in the next revision. > > Name: Maximum Reserved Under-Utilized Path (MRUP) > > > > Description: Find a path P such that (Min {(R(Lpi)- ru(Lpi)) / > > R(Lpi), i=1...K } ) is maximized. > > Regards, > Dhruv > > ---------- Forwarded message ---------- > From: Avantika <[email protected]> > Date: Fri, Jan 24, 2014 at 12:11 PM > Subject: Suggestion in draft-wu-pce-pcep-link-bw-utilization regarding > MRUP calculation > To: Dhruv Dhody <[email protected]>, Qin Wu <[email protected]>, " > [email protected]" <[email protected]> > Cc: Udayasree palle <[email protected]>, "[email protected]" < > [email protected]> > > > Hi Authors! > > > > I have a suggestion regarding the formula used for optimization using > objective function MRUP in draft-wu-pce-pcep-link-bw-utilization. > > > > As per the draft, > > > > Name: Maximum Reserved Under-Utilized Path (MRUP) > > > > Description: Find a path P such that (Min {(c(Lpi)- ru(Lpi)) / > > c(Lpi), i=1...K } ) is maximized. > > > > > > Let me take the example of below topology, > > > > 100(max reservable BW on each link) > > > > Source Destination > > A------------------------C > > | | > > | | > > | | > > | | > > B------------------------D > > > > LSP1 : BW 20 > > LSP2 : BW 20 > > LSP3 : BW 40 > > > > Every time a LSP is established path A-C, the RSVP-traffic flowing through > them, let's say, is approximately 60% of the current reserved. > > > > After each LSP is established, the output of the formula ((c(Lpi)- > ru(Lpi)) / c(Lpi)) > > Consider link A-C > > LSP1: (20 - 12)/20 > > LSP2: (40 - 24)/40 > > LSP3: (80 - 48)/80 > > > > Always remains as 0.4. > > > > In my opinion, if instead of using Current Reserved bandwidth, c(L) in the > above formula, if we use Maximum reservable bandwidth on link L, denoted R(L). > > > > Name: Maximum Reserved Under-Utilized Path (MRUP) > > > > Description: Find a path P such that (Min {(R(Lpi)- ru(Lpi)) / > > R(Lpi), i=1...K } ) is maximized. > > > > > > Consider link A-C > > LSP1 : (100 - 12)/100 = 0.88 > > LSP2 : (100 - 24)/100 = 0.76 > > LSP3 : (100 - 48)/100 = 0.52 > > > > This gives a much clearer reserved utilization for the link. > > > > Also, now if the OF MRUP is used for the path computation: > > > > LSP1 : A-C > > LSP2 : A-B-D-C > > LSP3 : A-C > > > > Hence we get a more diversified path using MRUP OF. > > > > Please let me know your opinion regarding the same. > > > > Regards, > > Avantika > > > > > > > >
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