1. Tiziana FerrariNetwork Metrics Requirements and Usage for WP11 Tiziana Ferrari Tiziana.Ferrari@cnaf.infn.it

2. Tiziana FerrariNetwork Metrics Requirements and Usage for WP12 Applicability examples Integration of network info into the scheduling policy: –To define the most suitable Storage Element for one or more Computing Elements Triggering of data transfers –To gather in a single Storage Element portions of data sets partioned among several Ses List of applications to be developed further…

3. Tiziana FerrariNetwork Metrics Requirements and Usage for WP13 Network information CloseSE attribute: –CloseSE = {(closeness 1, SE 1 ), …, (closeness n, SE n )} closeness(CE, SE) = max 0<i<m, 0<j<n {closeness(CE i,SE j )} –Closeness varies in [0,1] –0 = SE unreachable –1 = SE on the same LAN Definitions –r: Round Trip Time, R max : max RTT, –p loss : packet loss frequency; –th: throughput; th max : maximum throughput closeness i, j (p loss,r,th) = 0 if p loss 0 closeness i, j (p loss,r,th) = th / th max r/ rmax where 0 < < 1 otherwise

4. Tiziana FerrariNetwork Metrics Requirements and Usage for WP14 Closeness function Fig 1: alpha = 2Fig 2: alpha = 10

5. Tiziana FerrariNetwork Metrics Requirements and Usage for WP15 Triggering of data transfers Initial assumption: all the SEs in a given set SE list = (SE 1, SE 2, …, SE n ) are equally distant from a given CE Definitions: –Inter SE distance: D(SE i ) = 1 j n, j i closeness(SE i, SE j ) – I : data portion stored by each SE i –Optimization function: opt(SE i ) = min j D(SE j ) * i/ max where in [0,1] SE is the selected Storage Element for computing element CE iff: SE = SE i iff opt(SE i ) = min j D(SE j ) * i/ max