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COBRA Project. MSTP-TE Load Balancing: Some results. Benchmarking Carrier Ethernet Technologies Session AI.3 Krakow, Poland - April 30, 2008 Rémi Clavier - Orange Labs. Goals & Assumptions. Input data. Work done in collaboration with ALF Topology Define a common "Reference Topology"
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COBRA Project MSTP-TE Load Balancing:Some results Benchmarking Carrier Ethernet Technologies Session AI.3 Krakow, Poland - April 30, 2008 Rémi Clavier - Orange Labs
Input data • Work done in collaboration with ALF • Topology • Define a common "Reference Topology" • Define "variations" from this topology • To have a more exhaustive analysis • To take into account realistic FT aggregation topologies • Matrix • Define a common (more or less) realistic traffic matrix including • http,HSI, VoIP • Pear to Pear • IPTv • VPNs • Define variation from this Matrix • To try to catch P2P / P2MP influence
Some definitions • For each "variation", different experiments were done • CL/CO • CL (as Connection Less) • The Control Plane is the 802.1Q one (MSTP with 1, 3 or 6 trees) • The Management plane set the MSTP's parameters of the Control Plane • CO (as Connection Oriented) • No Control Plane, the forwarding is positioned by the management plane • LB/SP (for CO only) • LB (aka Load Balancing) • The tool tries to optimize (maximize) the load balancing over the full network • SP (aka Shortest Path) • The tool tries to optimize (minimize) the sum of the hops for all flows over the full network • A route is "acceptable" only if no link is overloaded over the full Network • MU/UN • MU (aka Multicast) • UN ( aka Unicast)
Variations of the topology for the experiment • V0 • Reference Topology, aggregation network fully meshed • All links 10 G • TV dispatcher directly connected to the aggregation Network • V0b • Reference Topology , aggregation network fully meshed • All DSLAM links 1G ; All other links (except one) of the Aggregation Network at 10G • TV dispatcher directly connected to the aggregation Network • V1 • Reference Topology, aggregation network fully meshed • All links 10 G • TV dispatcher outside the aggregation Network (core network) • V1b • Reference Topology , aggregation network fully meshed • All DSLAM links 1G ; All other links (except one) of the Aggregation Network at 10G • TV dispatcher outside the aggregation Network (core network) • V3 • Reference Topology but Aggregation network not meshed (Ring Aggregation topology) • All DSLAM links 1G ; All other links (except one) of the Aggregation Network at 10G • TV dispatcher outside the aggregation Network (core network)
Results criteria and format • Three major indicators chosen jointly with ALF (1 curve, two values) • PFD curve • Probability Density Function • The probability that the load (in term of capacity of the link) is inside a given interval • The CDF is the integral of the PDF and not used directly to compare results • The ME value • The average of the PDF function • May give information about the fact that the less loaded links are preferentially chosen • The SD value • The root mean square of the PDF curve • shows the dispersion of the load of links around the full network
Fully Meshed Aggregation network • All Links 10G • TV inside aggregation Network V0 • Analyze (to be discuss) • Multicast give a non negligible gain against "multi unicast" • For MU, no difference between CO and CL • For UN, CO seems better than CL • FT Remarks (from detailed results) • 3 trees are enough (no specific gain with 6 trees)
Fully Meshed Aggregation network • All Links (except one) 10G for the aggregation Networks, DSLAM links 1G • TV dispatcher outside aggregation Network V1b • Analyze • No "big" difference between CO and CL • LB give a better REm and a well better SD than SP in a CO context • PDF curve shows that CO/SP doesn't find a correct load balancing
Let us try to conclude …... keeping the door open for discussion
Preliminary conclusions • With MSTP, paths are constrained to follow "trees" • At first sight, this constraint could decrease load balancing performances compared to ELS networks • But, with a TE tool, MSTP gives the same results as CO networks in terms of load balancing • For a very loaded network and/or a network with links with different capacities of links • A centralized optimization gives better results (load balancing) than optimization based solely on the calculation of a Shortest Path • The centralized optimization tool gives equivalent performances for CL or CO networks with LB routing ("TE") algorithm • Other "well known" properties of MSTP are not impacted by load balancing optimization • Low cost • "Bad" convergence time • Compliant to standard • Natively multicast…