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Table 9 Notation used in the model

From: Stochastic hierarchical multiobjective routing model in MPLS networks with two service classes: an experimental study on imprecision and uncertainty issues

Notations

Description

O.f. calculation

 

W Q ( B ) = s S Q ( B ) A s c w s

Total expected network revenue associated with QoS(BE)

 

traffic flows

B Mm | Q = max s S Q { B ms }

Maximal average blocking probability among all QoS service

 

types

B ms | Q = 1 A s o f s F s A( f s )B( f s )

Mean blocking probabilities for flows of type s S Q

B Ms | Q = max f s F s {B( f s )}

Maximal blocking probability defined over all flows of

 

type s S Q

Blocking probabilities calculation

 

B(f s )

Node-to-node blocking probability for all flows f s F s

B ks = s d k ¯ , ρ k ¯ , C k

Blocking probabilities for micro-flows of service type s in

 

link l k

s

Basic function (implicit in the teletraffic analytical model)

 

to calculate B k s

Decision variables

 

R ¯ = s = 1 | S | R(s)

Network routing plans

R(s)= f s F s R( f s ),s S Q S B

Set of all the feasible routes for the traffic flows of type s

R(f s )=(rp(f s )), p=1,, M

First, second, , M-th choice route for flow f s

Path metrics and auxiliary parameters - MMRA-S2

 

m ks 1 = c ks Q ( B )

Marginal implied costs

m ks 2 =log(1 B ks )

Marginal blocking probabilities

D( f s )

Set of all feasible loopless paths for flow f s

Simulation parameters

 

T= [ T i j ]

Base matrix with offered bandwidth values

 

from node i to node j (Mbps)

α

Compensation parameter

t 0

Duration of the first stage of the initialization phase,

 

where only periodical updates of the estimate

 

of the offered traffic are performed

t 1

Duration of the second stage of the initialization phase,

 

where periodical updates of the estimate of the offered

 

traffic and of the routing plan are performed

twarm-up=t0+t1

Duration of the initialization phase

τ

Update period of the estimates of the offered traffic

 

and of the network routing plans

x ~ n ( f s )=(1b) x ~ n 1 ( f s )+b X ~ n 1 ( f s )

Estimate of the average traffic offered to the network

 

by the flow f s in the time interval [ n τ;(n+1)τ[

X ~ n 1 ( f s )

Estimator of the average value of the traffic offered

 

by f s to the network in the previous interval [ (n−1)τ;n τ[

b

Compromise value between the need to obtain a quick

 

response of the estimator to rapid fluctuations in X ~ ( f s )

 

and the stability of the long-run variations

Miscellany of auxiliary parameters

 

f s

Flow of service type s

S Q ( B )

Set of QoS(BE) service types

A s o

Total traffic offered by flows of type s

A s c

Carried traffic for service type s

A(f s )

Mean traffic offered associated with f s F s

w s

Expected revenue per call of service type s

ρ k s

Reduced traffic loads offered by flows of type s to l k

ρ k ¯ = ρ k 1 , , ρ k | S |

Vector of reduced traffic loads

d k s

Equivalent effective bandwidths for flows of type s in l k

d k ¯ = d k 1 , , d k | S |

Vector of equivalent effective bandwidths

d s

Required bandwidth for service s (kbps)

d s = d s u 0

Required effective bandwidth for service s (channels)

,E,G,

Test networks

|N|

Number of nodes in the network

||

Number of unidirectional links in the network

C k

Link bandwidth (Mbps)

C k = C k u 0

Link capacity (channels)

u 0

Basic unit capacity

h s

Average duration of a type s call

D s

Maximum number of arcs for a type s call

ξ(f s )

Function for choosing candidate paths for flow f s

 

for possible routing improvement

δ

Average node degree of a network