Q.S BASED ON OSPF Q.S BASED ON OSPF ROUTINGROUTING

BY : SHEMER SCHWARZBY : SHEMER SCHWARZ

ZIV KEDEMZIV KEDEM

WHAT IS Q.S ROUTING?WHAT IS Q.S ROUTING?

Q.S ROUTING IS THE PROCESS OF Q.S ROUTING IS THE PROCESS OF SELECTING THE PATH TO BE USED SELECTING THE PATH TO BE USED BY PACKETS OF A FLOW BASED ON BY PACKETS OF A FLOW BASED ON ITS Q.S REQUIREMENT, e.g., ITS Q.S REQUIREMENT, e.g., BANDWIDTH OR DELAY. BANDWIDTH OR DELAY.

WHY Q.S?WHY Q.S?

OPTIMIZE NETWORK RESOURCE OPTIMIZE NETWORK RESOURCE USAGE.USAGE.

INTERGRATE NETWORKS FOR INTERGRATE NETWORKS FOR VOISE, DATE AND MULTIMEDIA.VOISE, DATE AND MULTIMEDIA.

WHY NOT?WHY NOT?

INCREASED ROUTING PROTOCOL INCREASED ROUTING PROTOCOL OVERHEAD.OVERHEAD.

MORE COMPLEX AND FREQUENT MORE COMPLEX AND FREQUENT COMPUTATION.COMPUTATION.

PARAMETERS PARAMETERS INFLUENCING THE INFLUENCING THE

COMPARISONCOMPARISON

PATH SELECTION ALGORITHM.PATH SELECTION ALGORITHM. ACCURACY OF INFORMATION.ACCURACY OF INFORMATION. CHARACTERISTIC OF NETWORK CHARACTERISTIC OF NETWORK

TRAFFIC.TRAFFIC. NETWORK TOPOLOGY.NETWORK TOPOLOGY. ADDMISSION CONTROL.ADDMISSION CONTROL.

COMPUTATIONAL COST COMPUTATIONAL COST PARAMETERSPARAMETERS

PATH SELECTION CRITIRIA.PATH SELECTION CRITIRIA. TRIGGER FOR PATH SELECTIONTRIGGER FOR PATH SELECTION

(periodically,on demand and on (periodically,on demand and on update).update).

FLEXIBILITY IN SUPPORTING FLEXIBILITY IN SUPPORTING ALTERNATE PATH SELECTION ALTERNATE PATH SELECTION CHOISES.CHOISES.

PROTOCAOL OVERHEAD PROTOCAOL OVERHEAD PARAMETERSPARAMETERS

TRIGGERS FOR NETWORK STATE TRIGGERS FOR NETWORK STATE UPDATEUPDATE

RELATIVE CHANGE.RELATIVE CHANGE. ABSOLUTE CHANGE OR CLASS ABSOLUTE CHANGE OR CLASS

BASED TRIGGER.BASED TRIGGER. TIMER BASED TRIGGER.TIMER BASED TRIGGER.

PROTOCAOL OVERHEAD PROTOCAOL OVERHEAD PARAMETERS(2)PARAMETERS(2)

UPDATE CONTENTSUPDATE CONTENTS

2.2.EVALUATION ENVIRONMENTEVALUATION ENVIRONMENTPATH SELECTION(1)PATH SELECTION(1)

BASED ON BELLMAN-FORD.BASED ON BELLMAN-FORD. S(d)=<s(d,1),s(d,2),…,s(d,n)>S(d)=<s(d,1),s(d,2),…,s(d,n)>

s(d,h)-set of paths from ‘s’ to ‘d’ of s(d,h)-set of paths from ‘s’ to ‘d’ of lop length ‘h’.lop length ‘h’.

PATH SELECTION(2)PATH SELECTION(2)

Feasible path.Feasible path. Minimal hops.Minimal hops. Minimal cost.Minimal cost.

UPDATE POLICIESUPDATE POLICIES

THRESHOLD BASED UPDATE.THRESHOLD BASED UPDATE.

bw_c - the current value of available bw_c - the current value of available bandwidth.bandwidth.

bw_o - the last advertised value.bw_o - the last advertised value.

||bw_o - bw_c||/bw_o > th.||bw_o - bw_c||/bw_o > th.

UPDATE POLICIESUPDATE POLICIES

EQUAL BASED UPDATES.EQUAL BASED UPDATES.

(0,B) , (B,2B) , (2B,3B) , …(0,B) , (B,2B) , (2B,3B) , …

EXPONENTIAL CLASS BASED EXPONENTIAL CLASS BASED UPDATES.UPDATES.

(0,B) , (B,(f+1)B) , ((f+1)B ,(0,B) , (B,(f+1)B) , ((f+1)B ,

(f^2+f+1)B) , …(f^2+f+1)B) , …

HIGHER LEVEL HIGHER LEVEL ADDMISSION(1)ADDMISSION(1)

A LOCAL PER NODE CHECK DETEMINES IF A LOCAL PER NODE CHECK DETEMINES IF THE REQUEST IS ALLOWED TO CONTINUE.THE REQUEST IS ALLOWED TO CONTINUE.

(b_avail(i) - b_req) / b_capacity(i)(b_avail(i) - b_req) / b_capacity(i)

5% - one hop longer.5% - one hop longer.

10% - 2 hops longer.10% - 2 hops longer.

20% - 3 and more hops longer.20% - 3 and more hops longer.

HIGHER LEVEL HIGHER LEVEL ADDMISSION(2)ADDMISSION(2)

3. 3. PROTOCOL OVERHEADPROTOCOL OVERHEAD

FACTORS AFFECTING PROTOCOL FACTORS AFFECTING PROTOCOL OVERHEAD :OVERHEAD :

Trigger policy.Trigger policy. The sensitivity level of the The sensitivity level of the

triggering level.triggering level. The use of non-zero hold down The use of non-zero hold down

timer.timer.

E-Equal Class. T-Threshold based update.