ethernet bridging (mstp, spb/plsb)

research & development

MSTP-TE Load Balancing:Some results

Benchmarking Carrier Ethernet TechnologiesSession AI.3

Krakow, Poland - April 30, 2008

Rémi Clavier - Orange Labs

COBRA Project


Goals Goals&& Assumptions Assumptions

research & developmentFrance Telecom Group

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

Residential NO-1 NO-2 NO-3 NO-4 NO-5 NO-6 NO-11 NO-12 NO-13 NO-14 NO-15 NO-16NO-1 359.1 359.1 359.1 623.7 623.7 276.48NO-2 359.1 623.7 623.7 359.1 359.1 276.48NO-3 359.1 623.7 623.7 359.1 359.1 276.48NO-4 359.1 623.7 623.7 359.1 359.1 276.48NO-5 623.7 359.1 359.1 359.1 623.7 276.48NO-6 623.7 359.1 359.1 359.1 623.7 276.48NO-11 18.5 18.5 18.5NO-12 18.5 18.5 18.5NO-13 18.5 18.5 18.5NO-14 18.5 18.5 18.5NO-15NO-16 1455.9 1455.92 1455.92 1455.92 1455.92 1455.92

iptv NO-1 NO-2 NO-3 NO-4 NO-5 NO-6NO-15 520 520 520 520 520 520

vpn1 NO-1 NO-2 NO-3 NO-4 NO-5 NO-6NO-1 137.2 137.2 137.2 137.2 137.2NO-2 137.2 137.2 137.2 137.2 137.2NO-3 137.2 137.2 137.2 137.2 137.2NO-4 137.2 137.2 137.2 137.2 137.2NO-5 137.2 137.2 137.2 137.2 137.2NO-6 137.2 137.2 137.2 137.2 137.2

vpn23 NO-1 NO-2 NO-3 NO-4 NO-5 NO-6NO-1 58.6 58.6NO-2 58.6 58.6NO-3 58.6 58.6NO-4 58.6 58.6NO-5 58.6 58.6NO-6 58.6 58.6


ExperimentsExperiments


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)


Partial resultsPartial results


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

REm (percent) 15.2716SD (percent) 8614.98

Dens ity 0 < 10% < 20% < 30% < 40% < 50% < 60% < 70% < 80% < 90% < 100%CDF 1 19 27 32 35 40 40 40 40 40 40PDF 1 19 7 5 3 5 0 0 0 0 0

V0-Multicast, PDF/ Nb Root

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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)

REm - V0 - Abstract Of Results

14.5

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UNICO UNICL MULTICO MULTICL

SD - V0 - Abstract Of Results

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Fully Meshed Aggregation networkFully Meshed Aggregation networkAll Links 10GAll Links 10GTV inside aggregation NetworkTV inside 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

Fully Meshed Aggregation networkFully Meshed Aggregation networkAll Links (except one) 10G for the aggregation Networks, DSLAM All Links (except one) 10G for the aggregation Networks, DSLAM links 1Glinks 1GTV dispatcher outside aggregation NetworkTV dispatcher outside aggregation Network

REm - V1b - Abstract Of Results

16

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19.520

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PDF for MU & UNI

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SD CO Uni/MU


Let us try to conclude …Let us try to conclude … ... keeping the door open for discussion... keeping the door open for discussion


Some precautions to consider What is a good "Load Balancing" ???What is a good "Load Balancing" ???

Regarding the needs of the operatorRegarding the needs of the operator Regarding the technical context where analyzes are doneRegarding the technical context where analyzes are done Regarding … everything elseRegarding … everything else

What does appear in the results? What does appear in the results? The intrinsic properties of the network's technologies?The intrinsic properties of the network's technologies? … … or the properties of tools used (optimizers)?or the properties of tools used (optimizers)?

Take care about results that are given for one kind of topology For one traffic matrix Although many variations are proposed


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…

ethernet bridging (mstp, spb/plsb)

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