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Study on Adaptation of CDN RequestRouting to Scalable Conference System

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Title: Study on Adaptation of CDN RequestRouting to Scalable Conference System


1
Study on Adaptation of CDN Request-Routing to
Scalable Conference System
  • Toshiyuki KAWASAKI Koji OKAMURA
  • Graduate School of Information Science and
  • Electrical Engineering (ISEE), Kyushu University
  • Computing and Communications Center,
  • Kyushu University
  • Aug 28,2003

2
Contents
  • 1.Background
  • 2.Goal and approach
  • 3.Evaluation
  • 4.Consideration
  • 5.Conclusion

3
1.Background-H.323 conference system
  • H.323 conference system is popular
  • Remote conference
  • Remote medical care
  • Remote education
  • H.323
  • Standard of video conference
  • on IP networks
  • MCU(Multipoint Control Unit)
  • Enable multipoint conference
  • Mixing the video and audio streams

Host A
Host B
Host B
Host A
Host C
Host D
4
1.Background-Overload of MCU
  • Problem of H.323 multipoint conference system
  • When hosts (participants) increase

MCU may become overload ?load sharing is needed
?overload
MCU
  • Existing method of load sharing
  • Distribute the load to several MCUs

When more hosts increase
?MCUs may become overload after all

Lack of scalability for the number of hosts
?overload
5
2. Goal and approach -Load Sharing by Hosts
  • Proposal method
  • Dont use any MCUs
  • Hosts connect with each other
  • Hosts play a role of MCUs
  • Hosts distribute load
  • increase of hosts ?increase of MCUs

Existing method
Obtain scalability for the number of hosts
Proposal method
6
2. Goal and approach - Application Level Multicast
  • Problem of the multipoint conference system
    without MCU
  • Each host should select the host which it
    connects with.
  • Existing method
  • ALM ( Application Level Multicast)
  • Multicast on logical network (overlay network)
  • Hosts play the role of multicast router on
    logical network.

Lobby server
Make links
Make high cost links between ASs
Entry
IP address list
New host
AS1
AS2
Overlay network
7
2.Goal and approach - ORIO and CDN Request Routing
  • Proposal method ORIO(Optimal Routing Inter
    Organization)
  • Using CDN Request-Routing
  • CDN(Content Delivery Network)
  • Network of severs to distribute content
    efficiently
  • Load sharing by using many surrogates
  • Request Routing
  • Select the optimal surrogate for the clients
  • Tell clients their optimal surrogates

contents
select
notify
Redirection server
Origin server
notify
surrogate
surrogate
Delivery contents
surrogate
request
surrogate
client
client
client
client
client
client
8
2. Goal and approach - Request routing using DNS
  • Process of participation at ORIO
  • Request Routing using DNS
  • Prepare DNS to redirect requests.
  • New participants write the certain host name for
    participation
  • into the packets destination address.
  • DNS tell the optimal hosts IP address at name
    resolution.
  • ?Connected with its optimal host automatically

AS 3
DNS server
AS 1
select
133.x.x.xxx
conference.ac.jp(host name)
connect
133.x.x.xxx(IP address)
New host
AS 2
9
3.Evaluation-Evaluation Environment
Simulation based evaluation using network
simulator NS2
  • Evaluation standard
  • Maximum network load
  • Comparing with the method using ALM
  • Experimental Network
  • SuperSINET
  • The number of ASs is 18
  • The number of hosts per ASs is 64
  • Environment
  • Speakers? 1?Hosts? 1256
  • Change distribution of hosts
  • Change the number of active AS
  • Speakers 1128?Hosts128

Experimental Network(SuperSINET)
?Speakers the number of source hosts, hosts
the number of destination hosts
10
3.Evaluation-simulation under the 3 distribution
of hosts
Maximum use of bandwidth (kbps)
  • Speakers 1, Hosts 1256
  • Distribute hosts to 6 ASs
  • Measure under the 3 distribution of hosts
  • Concentrate at 1 area
  • Concentrate at 2 areas
  • Concentrate at 3 areas

1 area (ORIO) 2 area (ORIO) 3 area (ORIO)

1 area (ALM) 2 area (ALM) 3 area (ALM)
  • Result
  • the increase amount of network load is decreasing
    as the number of participants increase
  • ? Scalability to the number of hosts.
  • ORIO is better than ALM at load sharing

The number of hosts
11
3.Evaluation - Change the number of ASs
Maximum use of bandwidth (kbps)
  • Speakers1,Hosts1256
  • Changing the number of ASs which hosts belong to
  • Select hosts from 6 ASs
  • Select hosts from 12 ASs
  • Select hosts from 18 ASs
  • Result
  • ORIO is better than ALM at load sharing
  • ORIOs efficiency of load sharing become worse
    when the number of AS is small ( hosts per AS is
    big).
  • ? Policy of routing within AS should be
    improved.

The number of hosts
12
3.Evaluation - Speakers
Maximum use of bandwidth (Mbps)
  • Change the number of Speakers
    Speakers 1128 Hosts 128
  • Select hosts randomly
  • Result
  • Network load increase linearly at both ORIO and
    ALM.
  • ?Dont provide scalability in this case.
  • The number of speakers should be limited.

The number of speakers
13
4.Consideration-Efficiency of ORIO and
restriction of ALM
  • ORIO provide more efficient load sharing than
    ALM
  • Possible reason
  • ALM uses logical network for routing,
  • but ORIO doesnt use it.
  • In ALM, there are two restrictions in receiving
    streams
  • Receivable only from its neighbors on the overlay
    network
  • Receivable only from its upstream hosts

14
4.Consideration-restriction of ALM
  • Receivable only from its neighbors on the overlay
    network
  • Receivable only from its upstream hosts
  • ? Promote the concentration of the load

Concentrate the load
Concentrate the load
Concentrate the load
Concentrate the load
Speaker
Speaker
speaker
speaker
Host C
Host C
Host C
Host C
delay 9ms
delay 9ms
delay 5ms
delay 5ms
delay 7ms
delay 7ms
Router
Router
router
router
Cant use this link though it is useful
Cant use this link though it is useful
delay 10ms
delay 7ms
delay 7ms
delay 10ms
Not neighbor
B is not As upstream host (Bs delay is bigger
than A)
Host B
Host B
Host A
Host A
Host B
Host B
Host A
Host A
15
5.Conclusion
  • Existing multipoint conference system
  • MCU easily become overload
  • Method of load sharing
  • Any MCU is not used
  • Hosts play a role of MCUs instead
  • The system which tells the hosts
    their connection partner is required
  • CDN Request-Routing
  • Result
  • Prove the scalability of ORIO
  • Future work
  • Adding the function which support the hosts
    exiting process
  • Improve the policy of routing within AS
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