Off­Piste­QoS­aware­Off­Piste­QoS­aware­Routing­Protocol­Routing­Protocol­

By­Yigal­EliaspurBy­Yigal­Eliaspur

Problem­Background­Problem­Background­ The­main­challenge­in­QoS­routing­is­to­be­able­to­The­main­challenge­in­QoS­routing­is­to­be­able­to­

respond­to­respond­to­onlineonline­requests­with­­requests­with­ Reasonable­response­timeReasonable­response­time Minimal­network­overhead­(Messages,­Memory­Processing­Minimal­network­overhead­(Messages,­Memory­Processing­

time).­time).­ Minimal­probability­of­blocking­(requests­failure).­Minimal­probability­of­blocking­(requests­failure).­

A­typical­request­is­to­reserve­a­certain­resource­along­a­A­typical­request­is­to­reserve­a­certain­resource­along­a­path­from­a­transaction­source­to­a­transaction­path­from­a­transaction­source­to­a­transaction­destination.destination.

The­resource­may­be­an­additive­resource­(e.g.­delay)­The­resource­may­be­an­additive­resource­(e.g.­delay)­or/and­a­nonadditive­resource­(e.g.­bandwidth).­or/and­a­nonadditive­resource­(e.g.­bandwidth).­

The­request­may­be­applied­to­Unicast­or­Multicast­The­request­may­be­applied­to­Unicast­or­Multicast­traffic.traffic.

Available­SolutionsAvailable­Solutions The­solutions­today­can­be­partitioned­to­three­broad­The­solutions­today­can­be­partitioned­to­three­broad­

classes:classes: Source­routing­algorithmsSource­routing­algorithms

• Transforms­a­distributed­problem­into­a­centralized­one.Transforms­a­distributed­problem­into­a­centralized­one.• Maintaining­a­complete­global­state­in­each­node­of­dynamics­Maintaining­a­complete­global­state­in­each­node­of­dynamics­network­resources.­­network­resources.­­

Distributed­routing­algorithmsDistributed­routing­algorithms• The­path­computation­is­distributed­among­­the­intermediate­nodes­The­path­computation­is­distributed­among­­the­intermediate­nodes­between­the­source­and­the­destination.between­the­source­and­the­destination.

• Single­path­search­–­usually­assumes­global­state­in­each­node.Single­path­search­–­usually­assumes­global­state­in­each­node.• Multi­path­search­(flooding)­–­uses­only­local­state­in­each­node.Multi­path­search­(flooding)­–­uses­only­local­state­in­each­node.

Hierarchical­routing­algorithmsHierarchical­routing­algorithms• Each­node­maintains­only­a­partial­global­stateEach­node­maintains­only­a­partial­global­state• To­cope­with­the­scalability­problem­of­global­state­in­large­To­cope­with­the­scalability­problem­of­global­state­in­large­internetworks.­­internetworks.­­

Related­WorkRelated­Work Our­OPsAR­protocol­(Off­Piste­QoS­aware­Routing)­can­be­classified­Our­OPsAR­protocol­(Off­Piste­QoS­aware­Routing)­can­be­classified­

to­the­Multi­path,­to­the­Multi­path,­distributed­routing­algorithms­family.distributed­routing­algorithms­family. Others­works­related­to­this­family­are:Others­works­related­to­this­family­are:

Selective flooding Selective flooding –­multi­path­search­will­be­done­only­on­pre-–­multi­path­search­will­be­done­only­on­pre-computed­­routes.computed­­routes.

Ticket based probingTicket based probing­­-­Every­probing­(search)­message­is­supposed­­­-­Every­probing­(search)­message­is­supposed­to­carry­at­least­one­ticket,­and­thus­the­total­number­of­tickets­limit­the­to­carry­at­least­one­ticket,­and­thus­the­total­number­of­tickets­limit­the­multi­path­search.multi­path­search.

QMRP and S-QMRPQMRP and S-QMRP­(Scalable­-­Distributed­QoS­Multicast­Routing­­(Scalable­-­Distributed­QoS­Multicast­Routing­Protocol):Protocol):• The­unicast­route­towards­the­destination­is­checked­first.The­unicast­route­towards­the­destination­is­checked­first.• If­that­failed­selective­scanning­mechanism­is­applied.If­that­failed­selective­scanning­mechanism­is­applied.• The­scanning­is­controlled­by­Maximum­Branching­Degree­and­Maximum­The­scanning­is­controlled­by­Maximum­Branching­Degree­and­Maximum­

Branching­Level­parameters.Branching­Level­parameters. QOSMicQOSMic­­-­best­suited­to­a­multicast­environment,­since­it­looks­for­a­­­-­best­suited­to­a­multicast­environment,­since­it­looks­for­a­

point­on­a­multicast­tree­to­``hook''­on­the­new­receiver.­point­on­a­multicast­tree­to­``hook''­on­the­new­receiver.­

The­OPsAR­ProtocolThe­OPsAR­Protocol Our­main­Our­main­motivationmotivation­of­OPsAR­is­to­improve­tradeoff­between­the­­of­OPsAR­is­to­improve­tradeoff­between­the­

overhead­of­the­protocol­and­the­success­ratio­it­produces.­overhead­of­the­protocol­and­the­success­ratio­it­produces.­ In­OPsAR,­a­node­keeps­track­of­recent­QoS­messages­to­learn­In­OPsAR,­a­node­keeps­track­of­recent­QoS­messages­to­learn­

about­resource­availability­about­resource­availability­to­and­fromto­and­from­various­target­points.­­various­target­points.­ The­learning­is­reflected­in­the­node's­The­learning­is­reflected­in­the­node's­``knowledge state''.``knowledge state''.­­ Efficient­path­selection­is­been­done­by­leveraging­on­the­Efficient­path­selection­is­been­done­by­leveraging­on­the­

knowledge­state­at­the­nodes.­knowledge­state­at­the­nodes.­ The­OPsAR­protocol­is­built­of­3­main­stages:The­OPsAR­protocol­is­built­of­3­main­stages:

Try PhaseTry Phase­–­in­which­a­single­path­search­and­reservation­is­applied­­–­in­which­a­single­path­search­and­reservation­is­applied­from­the­transaction­source­to­the­transaction­destination.­from­the­transaction­source­to­the­transaction­destination.­

Scan PhaseScan Phase­–­in­which­a­multi­path­search­without­reservation­is­­–­in­which­a­multi­path­search­without­reservation­is­applied­from­the­transaction­destination­back­to­the­source.applied­from­the­transaction­destination­back­to­the­source.

Try 2 PhaseTry 2 Phase­–­in­which­the­scan­phase­results­are­evaluated­and­the­­–­in­which­the­scan­phase­results­are­evaluated­and­the­best­candidate­path­is­reserved­from­the­transaction­source­to­the­best­candidate­path­is­reserved­from­the­transaction­source­to­the­destination.destination.

Try­PhaseTry­Phase

A­path­search­from­the­transaction­source­toward­the­A­path­search­from­the­transaction­source­toward­the­transaction­target.transaction­target.

Try­phase­follows­the­shortest­path­as­long­as­it­has­the­Try­phase­follows­the­shortest­path­as­long­as­it­has­the­required­resources.­required­resources.­

The­deviation­from­the­shortest­path­takes­an­``off­piste''­The­deviation­from­the­shortest­path­takes­an­``off­piste''­route­­that­leverages­on­the­route­­that­leverages­on­the­knowledge stateknowledge state­to­optimize­­to­optimize­the­routing­protocol.­the­routing­protocol.­

Its­deviation­from­the­shortest­path­is­bounded­.Its­deviation­from­the­shortest­path­is­bounded­. If­resources­cannot­be­reserved­within­that­boundary,­the­If­resources­cannot­be­reserved­within­that­boundary,­the­

resources­which­have­already­been­reserved­are­resources­which­have­already­been­reserved­are­released,­and­a­request­is­sent­to­the­transaction­target­released,­and­a­request­is­sent­to­the­transaction­target­to­begin­the­Scan­phase.­­to­begin­the­Scan­phase.­­

Scan­PhaseScan­Phase The­scan­process­is­based­on­limited­Breadth­First­Search­(BFS)­The­scan­process­is­based­on­limited­Breadth­First­Search­(BFS)­

from­the­transaction­target­toward­the­transaction­source.from­the­transaction­target­toward­the­transaction­source. We­neither­reserve­resources­in­the­Scan­phase­nor­keep­any­state­We­neither­reserve­resources­in­the­Scan­phase­nor­keep­any­state­

that­relates­to­the­specific­scan.­that­relates­to­the­specific­scan.­ As­in­the­Try­Phase­the­scanning­process­takes­advantage­of­the­As­in­the­Try­Phase­the­scanning­process­takes­advantage­of­the­

knowledge­state­to­optimize­the­search.­knowledge­state­to­optimize­the­search.­ The­branching­limitation­is­done­by:The­branching­limitation­is­done­by:

TicketingTicketing­scheme­to­bound­the­total­number­of­paths.­­scheme­to­bound­the­total­number­of­paths.­ Maximum branching degree (MBD)Maximum branching degree (MBD)­at­each­node­in­order­to­increase­­at­each­node­in­order­to­increase­

the­variety­of­potential­paths­to­traverse.­the­variety­of­potential­paths­to­traverse.­ Off-piste counterOff-piste counter­to­limit­the­distance­from­the­shortest­path,­similar­to­­to­limit­the­distance­from­the­shortest­path,­similar­to­

the­Try­phase.­the­Try­phase.­ Branch­is­terminated­during­the­scanning­process­if:­Branch­is­terminated­during­the­scanning­process­if:­

Off­piste­limit­is­reached­and­the­unicast­route­does­not­have­the­Off­piste­limit­is­reached­and­the­unicast­route­does­not­have­the­resources.­resources.­

Or­when­no­outgoing­link­has­the­requested­resources.Or­when­no­outgoing­link­has­the­requested­resources.

Try­2­PhaseTry­2­Phase

If­the­transaction­source­receives­several­successful­scan­If­the­transaction­source­receives­several­successful­scan­messages,­it­initiates­the­Try­2­phase.messages,­it­initiates­the­Try­2­phase.

It­chooses­the­``best''­route­from­the­successful­scan­It­chooses­the­``best''­route­from­the­successful­scan­messages­and­asks­to­reserve­the­resources­along­that­messages­and­asks­to­reserve­the­resources­along­that­path.path.

If­reservation­failure­along­the­explicit­route­is­detected,If­reservation­failure­along­the­explicit­route­is­detected, The­OPsAR­tries­to­route­the­reservation­request­The­OPsAR­tries­to­route­the­reservation­request­

message­to­the­transaction­destination­using­alternative­message­to­the­transaction­destination­using­alternative­routes­that­­the­off­piste­mechanism­offers.routes­that­­the­off­piste­mechanism­offers.

If­that­fails­a­nack­message­is­returned­to­the­transaction­If­that­fails­a­nack­message­is­returned­to­the­transaction­source­indicating­the­need­to­choose­another­explicit­source­indicating­the­need­to­choose­another­explicit­route­from­the­previous­scan­result.­­route­from­the­previous­scan­result.­­

Knowledge­State­-­definitionKnowledge­State­-­definition Each­node­maintains­Each­node­maintains­

A­local­state­in­which­it­holds­its­links'­status­and­the­A­local­state­in­which­it­holds­its­links'­status­and­the­resource­availability­on­them.­resource­availability­on­them.­

A­bounded­list­of­records­A­bounded­list­of­records­• <target­nodes,­outgoing­link>­<target­nodes,­outgoing­link>­

For­each­record­the­resources­availability­is­For­each­record­the­resources­availability­is­maintained­with­respect­to­that­outgoing­link­:maintained­with­respect­to­that­outgoing­link­:• Max­BW­toward­the­target­node.Max­BW­toward­the­target­node.• Max­BW­from­the­target­node.­Max­BW­from­the­target­node.­

This­information­is­updated­occasionally­and­is­This­information­is­updated­occasionally­and­is­marked­to­identify­the­time­of­its­last­update.­marked­to­identify­the­time­of­its­last­update.­

This­time­is­used­for­aging­mechanism.This­time­is­used­for­aging­mechanism.

Knowledge­State­-­usageKnowledge­State­-­usage AnyAny­OPsAR­protocol­message­traversing­a­node­is­used­to­update­the­knowledge­state­(KS).­OPsAR­protocol­message­traversing­a­node­is­used­to­update­the­knowledge­state­(KS). Each­OPsAR­protocol­message­includes­the­following­relevant­fields:Each­OPsAR­protocol­message­includes­the­following­relevant­fields:

Max­BW­To­OriginMax­BW­To­Origin Max­BW­From­OriginMax­BW­From­Origin

There­are­three­main­operation­the­KS­is­involve­with:There­are­three­main­operation­the­KS­is­involve­with: KS­record­creation/updateKS­record­creation/update

JJ JJ

OPsAR­message­fields­updateOPsAR­message­fields­update

JJ

Routing­decisionRouting­decision• The­choice­is­made­according­to­the­resource­availability­along­the­various­links­toward­the­target,­and­according­to­how­recent­The­choice­is­made­according­to­the­resource­availability­along­the­various­links­toward­the­target,­and­according­to­how­recent­

that­information­is.that­information­is.• This­is­Based­on­three­levels­of­outgoing­links­(neighbors)­maintained­per­target­node:This­is­Based­on­three­levels­of­outgoing­links­(neighbors)­maintained­per­target­node:

FreshFresh StaleStale OldOld

Knowledge­State­–­Routing­Knowledge­State­–­Routing­decision­(cont.)decision­(cont.)

CandidateCandidate

Neighbors­groupNeighbors­group

CandidateCandidate

Next­hopNext­hop

Resource­Resource­information­inputinformation­input

FreshFresh unicastunicast End2EndEnd2End

FreshFresh AllAll End2EndEnd2End

~Fresh~Fresh unicastunicast Next­HopNext­Hop

StaleStale AllAll End2EndEnd2End

~Fresh~Fresh AllAll Next­HopNext­Hop

AllAll AllAll Next­HopNext­Hop

Simulation­ModelSimulation­Model NS­2­simulator­NS­2­simulator­ Power­Law­network­topologyPower­Law­network­topology

As­the­node­degree­increases,­the­number­of­nodes­with­that­degree­As­the­node­degree­increases,­the­number­of­nodes­with­that­degree­decreases­exponentially.­decreases­exponentially.­

Used­the­topology­generator­described­in­Osnat’s­work­(On­the­Used­the­topology­generator­described­in­Osnat’s­work­(On­the­tomography­of­networks­and­multicast­trees)­tomography­of­networks­and­multicast­trees)­

The­generator­was­extended­to­support­BW­allocation.The­generator­was­extended­to­support­BW­allocation. The­bandwidth­on­the­links­was­uniformly­distributed­from­The­bandwidth­on­the­links­was­uniformly­distributed­from­

{10,34,45,100}­Mb/s.{10,34,45,100}­Mb/s. In­order­to­make­sure­that­the­congestion­would­first­occur­in­the­core­In­order­to­make­sure­that­the­congestion­would­first­occur­in­the­core­

network­we­re­assigned­the­bandwidth­of­the­endpoints­to­1000Mb.­network­we­re­assigned­the­bandwidth­of­the­endpoints­to­1000Mb.­ We­also­conducted­tests­with­hierarchical­bandwidth­assignment­We­also­conducted­tests­with­hierarchical­bandwidth­assignment­

chosen­from­{10Mb,100Mb,1G,10G}­bits­per­second.­chosen­from­{10Mb,100Mb,1G,10G}­bits­per­second.­• This­backbone­/­metro­type­of­over­provisioning­BW­allocation­showed­This­backbone­/­metro­type­of­over­provisioning­BW­allocation­showed­

almost­no­congestion­for­BW­reservation­requests.almost­no­congestion­for­BW­reservation­requests.• Therefore,­the­topologies­simulated­were­­only­large­edge­networks­and­ISP­Therefore,­the­topologies­simulated­were­­only­large­edge­networks­and­ISP­

like­networks.­like­networks.­

Simulation­Basis­Simulation­Basis­ 600­nodes­was­used.­600­nodes­was­used.­ Transaction­endpoints­were­chosen­out­of­120­edge­nodes.Transaction­endpoints­were­chosen­out­of­120­edge­nodes. Most­of­the­graphs­are­the­result­of­10,000­transactions­performed­Most­of­the­graphs­are­the­result­of­10,000­transactions­performed­

on­six­different­generated­topologies.­on­six­different­generated­topologies.­ We­ran­each­simulation­on­5­different­protocol­types:­We­ran­each­simulation­on­5­different­protocol­types:­

Traditional RSVPTraditional RSVP­-­Allocates­the­QoS­requirement­along­the­unicast­­-­Allocates­the­QoS­requirement­along­the­unicast­route­toward­the­transaction­destination;­route­toward­the­transaction­destination;­

S QMRP*S QMRP*­-­Is­S-QMRP­adaptation­to­unicast­routing­­-­Is­S-QMRP­adaptation­to­unicast­routing­• Basically­it’s­the­same­as­OPsAR­but­without­KS­and­Off-Piste­counter­Basically­it’s­the­same­as­OPsAR­but­without­KS­and­Off-Piste­counter­

support.support. S QMRP*DS QMRP*D­–­Is­S-QMRP*­with­Off-Piste­counter­support.­–­Is­S-QMRP*­with­Off-Piste­counter­support. OPsAROPsAR­­ OPTOPT­-­Implemented­as­a­BFS­which­finds­the­shortest­path­that­fulfills­­-­Implemented­as­a­BFS­which­finds­the­shortest­path­that­fulfills­

the­bandwidth­QoS­requirements.­the­bandwidth­QoS­requirements.­ Message­overhead;­Message­overhead;­

Simulation­Basis­(cont.)Simulation­Basis­(cont.)

We­performed­the­following­simulation­and­We­performed­the­following­simulation­and­evaluate­their­relationship­to­the­reservation­evaluate­their­relationship­to­the­reservation­success­ratio:­success­ratio:­ Memory­usageMemory­usage Amount­of­concurrent­transactionsAmount­of­concurrent­transactions Number­of­edge­nodesNumber­of­edge­nodes Number­of­destination­nodesNumber­of­destination­nodes The­Cost­and­Performance­Gain­of­Using­Try&Scan­The­Cost­and­Performance­Gain­of­Using­Try&Scan­PhasesPhases

Gradual­Deployment­within­RSVP­FrameworkGradual­Deployment­within­RSVP­Framework

Memory­Usage­vs.­Success­Ratio­Memory­Usage­vs.­Success­Ratio­

Memory­Usage­vs.­Success­Ratio­Memory­Usage­vs.­Success­Ratio­(cont.)(cont.)

The­amount­of­memory­­sufficient­to­achieve­about­85%­The­amount­of­memory­­sufficient­to­achieve­about­85%­of­success­ratio­is­very­reasonable.­of­success­ratio­is­very­reasonable.­

The­memory­is­theoretically­bounded­by­The­memory­is­theoretically­bounded­by­ The­out­degree­of­a­core­node­(or­by­the­aged­out­threshold­The­out­degree­of­a­core­node­(or­by­the­aged­out­threshold­

which­is­9­in­our­case)­­which­is­9­in­our­case)­­ Times­the­number­of­possible­transaction­destination­nodes.­Times­the­number­of­possible­transaction­destination­nodes.­

In­the­­largest­simulation­done­this­theoretical­number­In­the­­largest­simulation­done­this­theoretical­number­was­160KB.was­160KB.

The­average­memory­consumption­was­about­10%­of­The­average­memory­consumption­was­about­10%­of­the­theoretical­bound.the­theoretical­bound.

Where­60KB­was­limit­-­the­actual­bound­set­in­the­Where­60KB­was­limit­-­the­actual­bound­set­in­the­simulation­code.­simulation­code.­

Concurrent­Transactions­vs.­Concurrent­Transactions­vs.­Success­Ratio­Success­Ratio­

Message­Overhead­vs.­Success­Message­Overhead­vs.­Success­Ratio­Ratio­

Message­Overhead­vs.­Success­Message­Overhead­vs.­Success­Ratio­(cont.)Ratio­(cont.)

We­studied­all­the­parameter's­possible­combination­within­a­specific­rangeWe­studied­all­the­parameter's­possible­combination­within­a­specific­range branching­degreebranching­degree scanning­deviationscanning­deviation and­number­of­tickets.­and­number­of­tickets.­

Each­simulation­result­generated­one­point­in­the­graph.Each­simulation­result­generated­one­point­in­the­graph. OPsAR­vs.­S-QMRP*OPsAR­vs.­S-QMRP*

For­the­same­amount­of­message­overhead,­the­OPsAR­improves­the­success­For­the­same­amount­of­message­overhead,­the­OPsAR­improves­the­success­ratio­up­to­30%­more­than­S­QMRP*.ratio­up­to­30%­more­than­S­QMRP*.

OPsAR­vs.­RSVPOPsAR­vs.­RSVP Increase­of­overhead­by­five­se­times­yields­about­three­times­the­success­ratio.Increase­of­overhead­by­five­se­times­yields­about­three­times­the­success­ratio. Another­point­to­consider­is­that­the­average­path­length­is­about­8­hops­when­Another­point­to­consider­is­that­the­average­path­length­is­about­8­hops­when­

deviation­is­allowed­and­the­4­hops­when­deviation­is­forbidden­(e.g.­RSVP).­deviation­is­allowed­and­the­4­hops­when­deviation­is­forbidden­(e.g.­RSVP).­ OPsAR­vs.­OPTOPsAR­vs.­OPT

The­overhead/sucess­ratio­of­OPT­is­­20.6­while­the­overhead/sucess­ratio­of­the­The­overhead/sucess­ratio­of­OPT­is­­20.6­while­the­overhead/sucess­ratio­of­the­OPsAR­in­200K­messages,­is­in­29.8­which­is­only­30%­more­then­the­OPT.­OPsAR­in­200K­messages,­is­in­29.8­which­is­only­30%­more­then­the­OPT.­

Number­of­Edge­Nodes­vs.­Number­of­Edge­Nodes­vs.­Success­Ratio­Success­Ratio­

Number­of­Destinations­Nodes­vs.­Number­of­Destinations­Nodes­vs.­Success­­RatioSuccess­­Ratio

Number­of­Destinations­Nodes­vs.­Number­of­Destinations­Nodes­vs.­Success­­Ratio­(cont.)Success­­Ratio­(cont.)

We­ran­the­simulation­with­a­constant­number­of­We­ran­the­simulation­with­a­constant­number­of­25%­edge­nodes­(as­opposed­to­the­20%­we­25%­edge­nodes­(as­opposed­to­the­20%­we­usually­used).­usually­used).­

The­number­of­candidate­destination­nodes­The­number­of­candidate­destination­nodes­varied­from­1%­up­to­the­whole­set­of­edge­varied­from­1%­up­to­the­whole­set­of­edge­nodes­(25%).­nodes­(25%).­

The­candidate­set­of­source­nodes­was­always­The­candidate­set­of­source­nodes­was­always­the­whole­set­of­edge­nodes.­the­whole­set­of­edge­nodes.­

Only­the­links­from­those­destination­nodes­were­Only­the­links­from­those­destination­nodes­were­assigned­­a­bandwidth­capacity­of­1000Mb.­assigned­­a­bandwidth­capacity­of­1000Mb.­

The­Cost­and­Performance­Gain­of­The­Cost­and­Performance­Gain­of­Using­Try&Scan­Phases­Using­Try&Scan­Phases­

The­Cost­and­Performance­Gain­of­The­Cost­and­Performance­Gain­of­Using­Try&Scan­Phases­(cont.)Using­Try&Scan­Phases­(cont.)

Scan­Phase­uses­extra­time­and­Scan­Phase­uses­extra­time­and­messages­over­Try­Phase.messages­over­Try­Phase.

Our­simulations­showed­that­the­time­to­Our­simulations­showed­that­the­time­to­complete­a­Try­followed­by­a­Scan­is­three­complete­a­Try­followed­by­a­Scan­is­three­times­the­time­it­takes­to­complete­the­Try­times­the­time­it­takes­to­complete­the­Try­phase­­alone.­phase­­alone.­

Gradual­Deployment­within­RSVP­Gradual­Deployment­within­RSVP­Framework­Framework­

Gradual­Deployment­within­RSVP­Gradual­Deployment­within­RSVP­Framework­(cont.)Framework­(cont.)

At­glance,­there­is­no­inherent­limitation­in­the­protocol­At­glance,­there­is­no­inherent­limitation­in­the­protocol­that­prohibits­its­use­in­an­incremental­manner.­that­prohibits­its­use­in­an­incremental­manner.­

The­``RSVP­only''­routers­were­selected­based­on­their­The­``RSVP­only''­routers­were­selected­based­on­their­distance­from­the­a­core.­distance­from­the­a­core.­

The­edge­routers­have­a­better­chance­to­be­chosen­as­``RSVP­The­edge­routers­have­a­better­chance­to­be­chosen­as­``RSVP­only''­­routers.­only''­­routers.­

From­the­learning­mechanism­perspective,­the­available­From­the­learning­mechanism­perspective,­the­available­capacity­of­the­links­betweens­``RSVP­only''­routers­is­capacity­of­the­links­betweens­``RSVP­only''­routers­is­ignored.ignored.

Future­work­can­focus­on­deployment­methods­for­the­Future­work­can­focus­on­deployment­methods­for­the­OPsAR­protocol­that­will­maintain­the­gain­obtained­from­OPsAR­protocol­that­will­maintain­the­gain­obtained­from­the­learning­mechanism.­the­learning­mechanism.­

Future­WorkFuture­Work Machine­learning­improvingMachine­learning­improving

The­overall­scheme­of­our­protocol­is­an­intelligent­the­choice­of­routes­from­a­full­Breadth­First­Search­The­overall­scheme­of­our­protocol­is­an­intelligent­the­choice­of­routes­from­a­full­Breadth­First­Search­algorithm­(BFS).­algorithm­(BFS).­

Future­on­research­can­focus­on­improving­the­educated­choice­of­routes­while­limiting­the­overhead­in­Future­on­research­can­focus­on­improving­the­educated­choice­of­routes­while­limiting­the­overhead­in­memory.­memory.­

We­expect­to­find­ways­to­use­machine­learning­techniques­to­achieve­that­goal.­We­expect­to­find­ways­to­use­machine­learning­techniques­to­achieve­that­goal.­ KS­Aggregations­KS­Aggregations­

Save­in­memory­by­aggregating­the­information,­using­techniques­like­longest­prefix­matching­on­Save­in­memory­by­aggregating­the­information,­using­techniques­like­longest­prefix­matching­on­transactions­destination.transactions­destination.

Packet­losses,­link/node­failures­Packet­losses,­link/node­failures­ Should­be­relatively­easy­using­timers­and­retries­for­messages,­and­using­soft­state­reservation.Should­be­relatively­easy­using­timers­and­retries­for­messages,­and­using­soft­state­reservation.

Additive­resources­Additive­resources­ Handling­additive­resources,­like­delay,­requires­minor­changes­d­to­the­protocols­presented.­Handling­additive­resources,­like­delay,­requires­minor­changes­d­to­the­protocols­presented.­

Tuning­the­KS­parameters­Tuning­the­KS­parameters­ Linear­increasing­the­fresh­neighbor­group­did­not­increase­the­performance­and­sometimes­cause­it­to­be­Linear­increasing­the­fresh­neighbor­group­did­not­increase­the­performance­and­sometimes­cause­it­to­be­

degraded.degraded. Increasing­the­age­out­threshold­–­does­not­improved­the­performance­either­even­though­­it­increase­the­Increasing­the­age­out­threshold­–­does­not­improved­the­performance­either­even­though­­it­increase­the­

total­memory­requirements.total­memory­requirements. Further­research­must­be­conducted­­in­order­to­explore­the­inter­dependencies­among­the­various­variables­Further­research­must­be­conducted­­in­order­to­explore­the­inter­dependencies­among­the­various­variables­

of­OPsAR,­and­to­automatically­learn­and­choose­the­optimal­values,­possibly­l­using­machine­learning­of­OPsAR,­and­to­automatically­learn­and­choose­the­optimal­values,­possibly­l­using­machine­learning­techniques.­techniques.­