A NOVEL SERVICE ROUTING METHOD

IN A SERVICE-ORIENTED NETWORK

Xiaoxiang Luo and Junde Song

Institute of Computer Science, BUPT, Beijing, China

Keywords: Service Routing, Service-oriented Network, Service Naming.

Abstract: In this paper, a service routing method is proposed to support Service Orchestration. The service-oriented

network is composed of service node and assisted node. A service node is designed to employ the service

execution and service routing functions. In our method, it is an efficient service routing as there is no centric

point to control the orchestration path, thus there’re no single point bottleneck problem. It is also a pervasive

method for a service-oriented network.

1 INTRODUCTION

Today, Web 2.0 and service-oriented architectures

(SOAs) are among the top issues. Both are poised

for exponential growth over the next few years, due

to their flexibility, cost effectiveness, and ease of

integration.

In a Service-oriented network, a user’s request is

decomposed into several single services and an

service orchestration serves as a composite to fulfil

users requirements. The concept of service routing is

to connect and unite service service nodes to form

higher-level target services. (F. Bennani, 2006). This

form of routing would serve as a coarse-grained

coordination mechanism, because it would govern

both the inclusion and order of services following a

service orchestration path.

In a Service-oriented network, routing is a

fundamental execution mechanism.

2 RELATED WORK

Most approaches in service composition literature

are based on Web Service, such as the Semantic

Web. (Torsten Klie, 2007), (Tim Berners-Lee,

2001).

The service implementation is based on the

interfaces described in standardized machine-

executable format (such as WSDL). With sharable

Web Services, tremendous reuse of applications

based on functionality may be achieved.

Automatic, dynamic or QoS-aware Web service

composition proposals are discussed. Those

proposals all act in the mode of the Client-Server

which means that tremendous protocol information

should be exchanged to achieve a user demanded ge-

neric service. (L.A.G. Dacosta, 2004), (Liangzhao

Zeng, 2004). The core managing service node ine-

vitably becomes the performance bottleneck.

Meanwhile, the method for composition planning is

computation intensive, and QoS limitations can be

identiﬁed. (Snehit Prabhu, 2007)

For service convergence, SOA (Service Oriented

Architecture) based service composition is em-

erging. SOA is defined as a paradigm for organizing

and utilizing distributed capabilities that may be

under the control of different ownership domains.

(M. MacKenzie, 2006). It provides a uniform means

to offer, discover, interact with and use capabilities

to produce desired effects consistent with mea-

surable preconditions and expectations”. The

services in SOA architecture are sharable and

reusable, however its architecture is not ﬂexible by

following the Client-Service mode, thus some

service type cannot be included (e.g. the services in

user device).

It is clear up to now that a service routing me-

thod is necessary in all service composition system

to support efficient service generation.

3 SERVICE ROUTING

3.1 Service-oriented Network

A service oriented network is constructed of two

560

Luo X. and Song J..

A NOVEL SERVICE ROUTING METHOD IN A SERVICE-ORIENTED NETWORK.

DOI: 10.5220/0003587605600563

In Proceedings of the 13th International Conference on Enterprise Information Systems (SSE-2011), pages 560-563

ISBN: 978-989-8425-53-9

 2011 SCITEPRESS (Science and Technology Publications, Lda.)

kinds of node: service node and assisting node

(1) Service Node

 Request Parser

The goal of the Request parser is to select the

best set of Single Service for user request. The

identiﬁcation of the minimal Single Service set

requires only an inspection of the service

functionality that fulﬁlls the task completely or in

parts. The shortest sequence(s) of Services are

selected. Then an Orchestration Plan is derived by

organizing the selected set of Service in a ordered

sequence.

 Service Execution Environment

It is an execution environment for service and

service integration where services are integrated for

various business applications.

Service with an input are executed in this

execution environment, and returns with an output.

 Service routing function

Service routing function is a matching process

based on local routing tables. It is in charge of

looking up in routing table for next service, and

sends the user request out again.

(2) Assisting Node

 Registry

Registry stores non-functional characteristics of

single Service, including service provider, service

location, service quality and abstract interface. The

information is described in a predeﬁned data

structure.

Registry updates the information of new

available services. As service registry increases, the

Request parser has more choice on services selected

for each task.

Whenever a service node cannot find a next

service node, the orchestration plan is forwarded to a

service registry. Then the next service node IP is

returned to the original service node and the plan is

forwarded to the next service node.

3.2 Service Routing Method

The network literature typically defines routing as

the processes when a router receives a message,

looks its destination up in a routing table, and sends

the message out again.

In service routing, local routing tables are also

maintained. But when a service node receives a user

request, it first does its own job, executes the single

service it is in charge of and then looks up in a table

for next service, and sends the user request out

again.

Whenever a user request is generated, it is ﬁrst

sent to the service Request Parser, it analyze and

then decompose the request into single services and

an Orchestration Plan is generated. Orchestration

Plan includes all the necessary single services and

the execution order of services.

Then the Request Parser forward Orchestration

Plan to the next node and the service routing method

controls the path and invokes each service in the list

to perform orchestration plan.

The basic operation of a service node is very

similar to an IP node. A request arrives on a face, a

look-up is done on its name and metadata, and then

an action is performed based on the result of that

lookup.

3.2.1 Orchestration Plan

The orchestration plan is routable service logic. It

involves a set of all the available services with the

service input and control information. It is written in

a script which wraps the selected services into a

service logic describing data ﬂow and control among

the ASs.

3.2.2 Service Node Design

Figure 1 is a core schematic of the service node. It

has three main data structures: the Service FIB

(Forwarding Information Base), Service Store

(service execution environment).

The Service Store is the same as the service list

that is to be executed in this service node. If the

service in the orchestration plan is found in the

service store, a service execution is initiated and the

output of this service is added to the plan. And then

the plan is to be forwarded downstream.

The Service FIB is used to forward

orchestration plan toward potential node(s) of

matching service.

Figure 1: Schematic of the service node.

A NOVEL SERVICE ROUTING METHOD IN A SERVICE-ORIENTED NETWORK

561

When an orchestration plan arrives on some

face, a lookup is done on its Service Name. The

index structure used for lookup is ordered so that a

Service Store match will be preferred over a FIB

match.

Thus if there is already a service in the Service

Store that matches the service listed in the plan, it

will initiate the execution of the single service. and

after the execution, the output of this service is

added to the plan. If there is more than a service in

the Service Store that matches the service listed in

the plan, it will initiate the execution of the services

in the order described in the orchestration plan. And

after the execution, the output of this service or these

services will be added to the plan.

If there is no service in the Service Store that

matches the service listed in the plan, the plan is to

be forwarded downstream.

Then a look up is done for a FIB match. If there

is a service in the FIB that matches the “first to be

done” service listed in the plan, the plan is sent out

one of the faces to the next service node.

If there is no match for the services in the FIB,

plan is forwarded to a service registry. Then the next

service node IP is returned to the original service

node and the plan is forwarded to the next service

node. The original service node added a record of

this <servicename, IP> pair to the FIB.

All service nodes can provide some service

executing and routing to next service node.

4 IMPLEMENTATION

To show the service routing process, we present an

example of E-Commerce service orchestration in an

e-bookshop scenario. We explain how the service

nodes can support a process for the user’s e-

purchase in the on-line bookshop. We depict the

orchestration process. In Figure 2, the whole process

is accomplished without user intervention.

Figure 2: Example of service orchestration for e-

commerce service.

The orchestration plan is passed to the involved

service nodes one by one. The most suitable service

is selected according to the predeﬁned optimal path

in the orchestration plan. At the end of each

execution of SERVICE, orchestration plan will be

sent to the consequent service node with an output

added to the orchestration plan. Note that this

procedure follows the optimal path and the service

nodes communicate with each other based on the

routing method without any centralized coordination

or control.

Figure 3 shows the Orchestration Plan described

in XMLschema. It shows how the plan controls the

path and invokes services in service node perform

orchestration. Single Service is identiﬁed with a

serviceName and each service node is associated

with a providerID. The two uniquely identiﬁes the

business en-tity offering that service. Each AS has

four attributes (serviceName, state, control path, data

path) deﬁned in names of (serviceName, state, Ctrl,

dataIn, DataOut). Once the service is successfully

accomplished, its attributes except serviceName are

changed. The execution order of AS is deﬁned by

thetag ”step”. Each AS may have multiple service

nodes provided with different negotiated QoS by

different provider. The service node candidates are

listed in each Service ﬁeld.

<?xml version="1.0" encoding="UTF-8" ?>

<op>

<e-commerce customerID=”cus1”

customerAddr= “ 215.35.67.33 ”

ecommerceID=”ec1”/>

<service serviceName=”S1” state= “ wait ”

ProviderID= “ sohu ” DataIN= “ Din1 ”

DataOUT=“Dout1”S1.addr=“null”/>

<service serviceName=”S2” state= “ wait ”

ProviderID= “ sohu ” DataIN= “ Din2 ”

DataOUT=“Dout2” S2.addr=“null”/>

</step>

<step stepnum= “ 2 ” Ctrl= “ parallel ”

returnpoint=“S2.addr”>

<service serviceName=”S3” state= “ wait ”

ProviderID=“sohu” Ctrl=“orderly”

DataIN= “ Din3 ” DataOUT= “ Dout3 ”

S3.addr=“null”/>

<service serviceName=”S4” state= “ wait ”

ProviderID=“ sohu” Ctrl=“OL1” DataIN=“

Din4” DataOUT=“Dout4” S4.addr=“null”/>

</step>

</op>

Figure 3: Orchestration Plan in XML Schema.

The orchestration plan is passed through

ICEIS 2011 - 13th International Conference on Enterprise Information Systems

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service node one by one. Each service node parses

the orchestration plan, execute the service and

forward this plan to the next service node. The main

method of dealing with the orchestration plan is

included.

Once the orchestration plan is created, the

Service node passes this orchestration plan to the

service node that performs the ﬁrst step. The address

of the service nodes is got from the FIB. Then the

service node checks if a service instance is able to be

created. The orchestration plan is passed to the

service node with the same serviceName one by one

until an available service node is found. The

available service node executes its operations

according to the control input (”Ctrl”) got from the

orchestration plan. The data input is a combination

of initial data input of this serviceName and the data

output of its previous Service. If successfully

executed, the state of this AS is marked ”success”.

And its ”ProviderID” ﬁeld is ﬁlled and it is used for

charging afterwards. Its ”DataOut” ﬁeld is ﬁlled and

it is used for constructing the input of next service.

Then the orchestration plan is passed to the next

service node that performs the second step in the

orchestration plan.

The above process is repeated until all the steps

are successfully passed. The last service node passed

the orchestration plan back to the customer.

The orchestration plan is rounded off until

accomplished.

5 CONCLUSIONS

In this paper, a service routing method is proposed

to support Service Orchestration. The service-

oriented network is composed of service node and

assisted node. A service node is designed to employ

the service execution and service routing functions.

In our method, it is an efficient service routing as

there is no centric point to control the orchestration

path, thus there’re no single point bottleneck

problem. It is also a pervasive method for a service-

oriented network.

ACKNOWLEDGEMENTS

This work is ﬁnancially supported by Program for

New Century Excellent Talents in University,

No.NCET-08-0738; and the innovation technology

star program of Beijing under grant No.2007A045.

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