Fujitsu Laboratories Ltd. 1APNOMS2003

A QoS Control Method Cooperating with a Dynamic Lo

ad 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

Fujitsu Laboratories Ltd. 2APNOMS2003

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

Fujitsu Laboratories Ltd. 3APNOMS2003

Our Approach to IP Traffic Control

QoS: quality of serviceSLA: service level agreementSPF: shortest path first

Level of

netw

ork

effi

cien

cy

TrafficEngineering (TE)

Minimum hop routing

+Explicit routing

+Multi route

& path

control

+Dynamic flow

splitting

BestEffort

＋Packet- priority

mechanism

＋Admissionpolicing

shaping ﾞ

＋Performance monitoringreporting

＋Account-refund

Connectionless approach(Diffserv)

Connection-orientedapproach(IntServ)

Explicit path setup

Static load balancing

Dynamic load balancing

Low High

Low

High

Level of QoS/SLA

Future

Hop-by-hopforwarding

Proposed method

Fujitsu Laboratories Ltd. 4APNOMS2003

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 RerouteAchieves highly reliabile network through high-speed failure recovery

Fujitsu Laboratories Ltd. 5APNOMS2003

Basic Architecture of Proposed Method- Cooperation between dynamic load balancing and providing QoS guarantee -

TE Controller

QoS path control for guaranteed class traffic

QoS path Bandwidth reserved High priority at scheduling Optimum route considering both network and application server resources MPLS: multi-protocol label switching

MPLS Network

Best Effort path Original path = minimum hop route Detour route used when there is congestion

Application Server

Statistics monitoring (Network, Application servers)

User

QoS request

Load balancing control for best effort traffic

Admission control

Fujitsu Laboratories Ltd. 6APNOMS2003

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)

link costserver cost

User

TOTAL COST is

MINIMUM!

Link D-E cost is high…

A

B

CD

E

server cost is high…

Fujitsu Laboratories Ltd. 7APNOMS2003

Evaluation of QoS Routing:Metrics and Model• Metrics

– Number of QoS requests accepted

– Average number of hops in QoS paths

Compared with• LSL method

(lowest server load)

• DNS method (domain name 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)

OC3 (155 Mbps)

T3 (45 Mbps)

Server locationcandidate

Select server with lowest load Select minimum cost

route to serverSelect nearest server

1st step

2nd step

Fujitsu Laboratories Ltd. 8APNOMS2003

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

0

100

200

300

400

Number of QoS requests

Nu

mb

er

of

req

uests

accep

ted

0 200

400 600 8000 200 400 600 800 Number of QoS requests

2.83.03.2

2.0

2.6

2.4

2.2

1.8

Avera

ge n

um

ber

of

hop

s

DNS method

Our Proposal

LSL method

Fujitsu Laboratories Ltd. 9APNOMS2003

Evaluation of Dynamic Load Balancing:Metric, Model, and Conditions

• Evaluate effect of dynamic load balancing under GS traffic conditions

• MetricThroughput of BE traffic

• Model5-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

100 Mbps

BE: 50 Mbps

GS

Reserved

Actual GS traffic

Fujitsu Laboratories Ltd. 10APNOMS2003

Evaluation of Dynamic Load Balancing: Results

Time [s]

Th

rou

gh

pu

t [M

bp

s]

Actual GS trafficActual GS traffic

BE traffic with D-LBD-LB1 (condition A, solid line)D-LB2 (condition B, × signs)

BE traffic with D-LBD-LB1 (condition A, solid line)D-LB2 (condition B, × signs)

BE traffic without D-LBBE traffic without D-LB

Bandwidth reservedfor GS traffic

Throughput decreases because load cannot be moved to other available links.

Throughput decreases because load cannot be moved to other available links.

•Input BE Traffic = 50 Mbps (fixed)

Throughput remains almost maximum.

Throughput remains almost maximum.

•D-LB:Dynamic load balancing

Fujitsu Laboratories Ltd. 11APNOMS2003

Implementation

Path-setting status display

- Snapshot of Operation Screen -

Click

Control statusdisplay panel(Path setting, load balancing, etc.)

Detailed path information

Fujitsu Laboratories Ltd. 12APNOMS2003

Conclusion & Future Work

ConclusionProposed 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