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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
2005
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
2005
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
2005
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
2005
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
2005
UNIVERSITY OF JYVÄSKYLÄ
Results
Low utilization – Throughput
2005
UNIVERSITY OF JYVÄSKYLÄ
Results
High utilization – Delay
2005
UNIVERSITY OF JYVÄSKYLÄ
Results
High utilization – Loss
2005
UNIVERSITY OF JYVÄSKYLÄ
Results
High utilization – Throughput
2005
UNIVERSITY OF JYVÄSKYLÄ
Results
Background traffic’s effect on throughput
2005
UNIVERSITY OF JYVÄSKYLÄ
Results
Background traffic’s effect on delay
2005
UNIVERSITY OF JYVÄSKYLÄ
Results
Background traffic’s effect on loss
2005
UNIVERSITY OF JYVÄSKYLÄ
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
2005
UNIVERSITY OF JYVÄSKYLÄ
ADC network topology
2005
UNIVERSITY OF JYVÄSKYLÄ
The end