2005

UNIVERSITY OF JYVÄSKYLÄ

Multicast Admission Control in DiffServ Networks

Department of Mathematical Information Technology

University of Jyväskylä

Finland

2005

UNIVERSITY OF JYVÄSKYLÄ

Introduction

IPTV, video conferences, etc. are more and more transferred in the IP networks nowadays than earlier

Video services demand strict QoS limits in terms of delay, jitter and packet loss

Multicast is a relevant transmission mechanism for these services

Differentiated Services is likely to be the most used QoS architecture in future

2005

UNIVERSITY OF JYVÄSKYLÄ

The Methods

There are three different admission control methods; Measurement based 1&2 and Parameter based

The methods are distributed to the edge nodes Based on filtering the join requests from customers The admission control methods are divided into three

distinct phases

2005

UNIVERSITY OF JYVÄSKYLÄ

Phase 1 – Edge test

Is common for all the methods

If the edge router that receives the join request already is forwarding the particular group, the join is automatically accepted

Otherwise, the method moves to the phase 2 before making any decisions

Customer

Customer

Customer

Multicastserver

Edge Edge

Edge

Core

JoinRequest

Accept

2005

UNIVERSITY OF JYVÄSKYLÄ

Phase 2 – Bandwidth test (1/2)

Measurement based methods 1 & 2:

Measurement 1 inspects if there is enough room on the links for the new receiver

Measurement 2, on the other hand, inspects if there is room within the class on every link

Based on MGRIP protocol Checks only the path between

egress edge node and branching node

Only the links whose utilization would increase are inspected

Customer

Customer

Customer

Multicastserver

Edge Edge

Edge

Core

JoinRequest

GRIPTest

BranchingNode

2005

UNIVERSITY OF JYVÄSKYLÄ

Phase 2 – Bandwidth test (2/2) Parameter based

method: The available bandwidth

is aproximated using the following equation:

Other assumptions are the same than with measurement based methods 1 & 2

Customer

Customer

Customer

Multicastserver

Edge Edge

Edge

Core

JoinRequest

GRIPTest

BranchingNode

)()( , flowiGtotii RNBwB

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UNIVERSITY OF JYVÄSKYLÄ

Phase 3 – Measurement test (1/2)

Methods Measurement 1 and 2: Egress edge joins the group, receives n first packets and

calculates loss, delay and jitter for the packets Exponential average of current and history results is used

to compare against defined limits

Uses packets’ RTP headers to calculate QoS parameters

currPwPwP expexp 1

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UNIVERSITY OF JYVÄSKYLÄ

Phase 3 – Measurement test (2/2)

Parameter based method: The maximum end-to-end delay, that can occur on the

path, is approximated using the following equation:

In our simulation environment, every node tracks the number of active connections it is forwarding

1

11

, )(k

j

ji

i

ik

j j

ijij

i

ii p

L

r

LFD

2005

UNIVERSITY OF JYVÄSKYLÄ

Simulations

Simulations were done with ”Network Simulator 2” Traffic of two customers was measured and other

customers produced the background traffic FTP, IPTV and video conference were used as the

applications Video traffic was produced from real captured video

stream

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UNIVERSITY OF JYVÄSKYLÄ

Simulation topology

Core

FTPserver

d

Edge

Edge

Edge

Edge

EdgeCore Core

Multicast servers

Measuredconferencecustomer

MeasuredIPTV

customer

Multicast customers Multicast customers

Multicast customers

FTP customers

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UNIVERSITY OF JYVÄSKYLÄ

Results

Tens of identical simulations with different background traffic loads were ran

First case shows a situation in a slightly loaded network Second case shows a situation with more loaded network The last case presents the influence of backgroud traffic

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UNIVERSITY OF JYVÄSKYLÄ

Results

Low utilization – Throughput

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UNIVERSITY OF JYVÄSKYLÄ

Results

High utilization – Delay

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UNIVERSITY OF JYVÄSKYLÄ

Results

High utilization – Loss

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UNIVERSITY OF JYVÄSKYLÄ

Results

High utilization – Throughput

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UNIVERSITY OF JYVÄSKYLÄ

Results

Background traffic’s effect on throughput

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UNIVERSITY OF JYVÄSKYLÄ

Results

Background traffic’s effect on delay

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UNIVERSITY OF JYVÄSKYLÄ

Results

Background traffic’s effect on loss

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Conclusions based on simulations

The need for admission control can be seen clearly Our simple admission control method gives better quality

for the customers being served Decreased throughput and rejection of some of the

requests is the cost of the method

2005

UNIVERSITY OF JYVÄSKYLÄ

ADC implementation

Linux workstation with more than 1 NIC as a Edge router XORP is an open source IP router platform which is used

to perform the router functionality Unix IPtables is used to filter the packets needed for

admission control decisions and measuring purposes ADC implementation performs packet loss, jitter and

delay calculations which it uses for decision making Next, a multicast receiver implementations will be done to

easily measure the quality of service experienced by the receivers

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UNIVERSITY OF JYVÄSKYLÄ

ADC network topology

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UNIVERSITY OF JYVÄSKYLÄ

The end