Transcript Examination of QoS control method based on traffic

A QoS Control Method
Cooperating with a Dynamic
Load Balancing Mechanism
Akiko Okamura, Koji Nakamichi, Hitoshi Yamada and Akira Chugo
Fujitsu Laboratories Ltd.
4-1-1, Kamikodanaka, Nakahara, Kawasaki, 211-8588, Japan
Telephone: +81-44-754-2635 Fax: +81-44-754-2741
E-mail address: {akikoo, nakamichi, hitoshi, chugo}@flab.fujitsu.co.jp
APNOMS2003
Fujitsu Laboratories Ltd.
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Introduction
• Current IP network problems
– End user's viewpoint
• Degraded of performance (e.g., lowered throughput and increased
delay) due to congestion
– Network operator's viewpoint
• Profits do not improve though traffic increases every year
• Frequent bandwidth increases needed to support traffic increases
• Services supporting usage-based billing are limited
• To overcome these problems
– Provide QoS guaranteed service
– Develop fee/charge system based on network QoS
– Use network resources efficiently
--> IP traffic control mechanism is required
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Fujitsu Laboratories Ltd.
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Our Approach to IP Traffic Control
Level of network efficiency
High
Traffic
Engineering (TE)
+Dynamic
flow splitting
Dynamic load
balancing
+Multi route
&
path control
Static load balancing
Minimum hop
routing
Hop-by-hop
forwarding
QoS: quality of service
SLA: service level agreement
SPF: shortest path first
Best
Effort
Low
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Future
Explicit
path setup
+Explicit
routing
Low
Proposed
method
Connectionless
approach
(Diffserv)
＋
Packetpriority
mechanism
Connectionoriented
approach
(IntServ)
＋
＋
＋
Admission Performance
Accountmonitoring
policing
refund
reporting
shaping ﾞ
Level of QoS/SLA
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High
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Traffic Engineering (TE)
• Description
– Improves traffic performance
– Facilitates reliable network operations
– A main application of multiprotocol label switching
(MPLS)
Constraint-based routing (explicit routing)
• Example Applications
– Static/dynamic load balancing
• Achieves highly reliabile network by avoiding congestion/failure
• Enables efficient use of bandwidth resources
--> Functions of dynamic load balancing have been proposed
– Fast Reroute
Achieves highly reliabile network through high-speed failure
recovery
APNOMS2003
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Basic Architecture of Proposed Method
- Cooperation between dynamic load balancing and providing QoS guarantee TE Controller
 Admission control
 Statistics monitoring
(Network, Application servers)
 Load balancing control
for best effort traffic
QoS
request
Application
Server
 QoS path control for
guaranteed class
traffic
User
QoS path
 Bandwidth reserved
 High priority at scheduling
 Optimum route considering
both network and application
server resources
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MPLS Network
Best Effort path
 Original path =
minimum hop route
 Detour route used
when there is congestion
MPLS: multi-protocol label switching
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QoS Routing Algorithm
• Minimize total cost of link and server
total cost = server cost +
link cost
server cost: 1/(residual available output rate)
link cost: 1/(residual available bandwidth)
server cost is
high…
B
A
C
D
E
User
Link D-E cost
is high…
link cost
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TOTAL COST
is MINIMUM!
server cost
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Evaluation of QoS Routing:Metrics and Model
• Metrics
– Number of QoS requests accepted
– Average number of hops in QoS paths
1st step
Compared with
Select server
with lowest load
• LSL method
(lowest server load)
• DNS method
(domain name server)
Select nearest
server
2nd step
Select minimum cost
route to server
• Simulation model
– ISP network, 19 nodes
– Application servers
• Four
• Capacity of 500 Mbps
– QoS requests
• 1-10 Mbps bandwidth guarantee (random)
• User’s edge selected at random (user’s edge ≠ server’s edge)
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Server location
candidate
OC3 (155 Mbps)
T3 (45 Mbps)
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Evaluation of QoS Routing: Results
• Effect of QoS routing considering both server and network
loads
– Accommodates many more requests
– Provides QoS path with the smallest number of hops
Average number of hops
Number of requests accepted
400
300
200
100
0
0
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200
400
600
Number of QoS requests
800
Fujitsu Laboratories Ltd.
3.2
3.0
2.8
LSL method
DNS method
2.6
2.4
2.2
2.0
1.8
Our Proposal
0
200 400 600 800
Number of QoS requests
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Evaluation of Dynamic Load Balancing:
Metric, Model, and Conditions
• Evaluate effect of dynamic load balancing under GS traffic
conditions
• Metric
100 Mbps
Throughput of BE traffic
BE: 50 Mbps
• Model
5-node-ring model with 100 Mbps links
• Conditions
– 50 Mbps BE traffic
– Bandwidth reserved for GS
traffic is increases to 80 Mbps.
– Actual amount of GS traffic fluctuates
– Congestion detection conditions
A) Actual (GS+BE) traffic > 80 Mbps
B) (Reserved GS + Actual BE) traffic > 80 Mbps
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Fujitsu Laboratories Ltd.
GS
Reserved
Actual GS traffic
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Evaluation of Dynamic Load Balancing:
Results
Throughput remains
almost maximum.
Throughput [Mbps]
BE traffic with D-LB
D-LB1 (condition A, solid line)
D-LB2 (condition B, × signs)
•Input BE Traffic
= 50 Mbps (fixed)
•D-LB:Dynamic load
balancing
Bandwidth reserved
for GS traffic
BE traffic without D-LB
Actual GS traffic
Time [s]
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Fujitsu Laboratories Ltd.
Throughput decreases
because load cannot be
moved to other available
links.
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Implementation
- Snapshot of Operation Screen Control status
display panel
(Path setting, load
balancing, etc.)
Path-setting status display
Detailed path information
Click
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Conclusion & Future Work
Conclusion
Proposed method effectively utilizes resource while providing QoS
• QoS routing based on network and server loads
– Number of QoS requests accepted is improved
– Server and network load balancing are achieved
• Use of dynamic load balancing effectively provides QoS-guaranteed
service
– Degradation in BE traffic throughput when GS traffic is fluctuating is avoided
Future work
• Evaluation of performance in large-scale network
• Development of more advanced QoS control method based on TE
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Fujitsu Laboratories Ltd.
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