Enterprise Integration EAI vs. SOA vs. ESB

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EAI vs. SOA vs. ESB

En t e r pr ise I n t e gr a t ion EAI vs. SOA vs. ESB Aut hor - Anurag Goel

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EAI vs. SOA vs. ESB

T ABLE OF CON TEN TS 1

I N TROD UCTI ON ................................................................................................ 4

2

SOA .................................................................................................................. 4

3

EAI ................................................................................................................... 5 3.1 3.2

HUB/ SPOKE.................................................................................................. 5 BUS .......................................................................................................... 7

4

ESB ................................................................................................................... 9

5

CON CLUSI ON .................................................................................................. 1 0

6

TAKEAW AYS SUM M ARY................................................................................... 1 2

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EAI vs. SOA vs. ESB

1

I N TROD UCTI ON

This paper aim s t o bring clarit y t o t erm s EAI , ESB, SOA and provide a clear dist inct ion. Also t his paper would discuss archit ect ure opt ions available for ent erprise int egrat ion and what t hese opt ions are m ost suit able for. Finally t his paper would address t he discussions we have seen in various forum s about whet her EAI is going t o be replaced by SOA or ESB.

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SOA

Service orient ed archit ect ure is approach t o have soft ware resources in an ent erprise available and discoverable on net work as well defined services. Each service would achieve a predefined business obj ect ive and perform discret e unit s of work. The services are independent and do not depend on t he cont ext or st at e of t he ot her services. They work wit hin dist ribut ed syst em s archit ect ure. Earlier SOA used COM or ORB based on CORBA specificat ions and recent SOA st ress on web services using st andard descript ion ( WSDL) , discovery ( UDDI ) and m essaging ( SOAP) . Service orient ed archit ect ure m ay or m ay not use web services but yes web services provide a sim ple way t owards service orient ed archit ect ure albeit wit h t he age old securit y and reliabilit y lim it at ions.

3

EAI

Ent erprise applicat ion int egrat ion is a business need t o m ake diverse applicat ions in an ent erprise including part ner syst em s t o com m unicat e t o each ot her t o achieve a business obj ect ive in a seam less reliable fashion irrespect ive of plat form and geographical locat ion of t hese applicat ions. I t is a business need and business never dies it only evolves. I have seen people saying t hat EAI is a t hing of past now SOA is here, it is j ust like saying “ t ransport at ion is a t hing of past now road is here” . EAI com prises of m essage accept ance, t ransform at ion, t ranslat ion, rout ing, m essage delivery and business process m anagem ent . Usually m essages t ransport at ion is asynchronous but for a business need it can be synchronous as well. There are t wo basic archit ect ures t o achieve t his, bus and hub/ spoke archit ect ure. Bot h of t hese can be used t o develop services and t hen it also becom es service orient at ed archit ect ure.

3 .1 H UB / S POKE Hub/ Spoke archit ect ure uses a cent ralized broker ( Hub) and adapt ers ( Spoke) which connect applicat ions t o Hub. Spoke connect t o applicat ion and convert applicat ion dat a form at t o a form at which Hub underst ands and vice versa. Hub on t he ot her hand brokers all m essages and t akes care of cont ent t ransform at ion/ t ranslat ion of t he incom ing m essage int o a form at t he dest inat ion syst em underst ands and rout ing t he m essage. Adapt ers t ake dat a from source applicat ion and publish m essages t o t he m essage broker, which, in t urn, does t ransform at ion/ t ranslat ion/ rout ing and passes m essages t o subscribing adapt er which sends it t o dest inat ion applicat ion( s) . Having a single Hub m akes syst em wit h t his archit ect ure easy t o m anage but scalabilit y t akes a hit . At som e point of t im e as num ber of m essages increase, scalabilit y get s dependent on hardware. Having a bigger box t o scale applicat ion has never been an ideal solut ion so t o overcom e t his lim it at ion m ost vendors have incorporat ed t he concept of federat ed hub and spoke archit ect ure in which m ult iple hubs can be present , each hub would have local m et adat a and rules as well as global m et adat a. Changes t o global rules and m et adat a are aut om at ically propagat ed t o ot her

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EAI vs. SOA vs. ESB

hubs. Federat ed hub spoke archit ect ure alleviat es scalabilit y issue while cent ral m anagem ent of m ult iple hubs m akes t his archit ect ure easy t o m anage and brings down support cost .

3 .2 BUS Bus archit ect ure uses a cent ral m essaging backbone ( bus) for m essage propagat ion. Applicat ions would publish m essages t o bus using adapt ers. These m essages would flow t o subscribing applicat ions using m essage bus. Subscribing applicat ions will have adapt ers which would t ake m essage from bus and t ransform t he m essage int o a form at required for t he applicat ion. Key difference bet ween hub/ spoke and bus t opology is t hat for t he bus archit ect ure, t he int egrat ion engine t hat perform s m essage t ransform at ion and rout ing is dist ribut ed in t he applicat ion adapt ers and bus archit ect ure requires an applicat ion adapt er t o run on t he sam e plat form as t he original applicat ions. Since adapt ers have int egrat ion engine and run on sam e plat form on which source and t arget applicat ions run, t his scales m uch bet t er and is com plex t o m aint ain com pared t o hub/ spoke t opology.

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EAI vs. SOA vs. ESB

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ESB

Ent erprise service bus is an infrast ruct ure t o facilit at e SOA. I t gives API which can be used t o develop services and m akes services int eract wit h each ot her reliably. Technically ESB is a m essaging backbone which does prot ocol conversion, m essage form at t ransform at ion, rout ing, accept and deliver m essages from various services and applicat ion which are linked t o ESB. Current EAI landscape is seeing m any vendors who offer ent erprise service bus and claim it t o be a brand new concept . This brings a quest ion on what exact ly is t he difference bet ween ESB and t he bus based im plem ent at ions which have been t here in m arket for quit e a long t im e now. Act ually t here is not m uch difference bet ween ESB and propriet ary buses except for a few subt le ones. Main difference bet ween ESB and propriet ary bus im plem ent at ion is of cost which is significant ly low for ESB. Reason for t his cost difference is t wo fold, first propriet ary bus offers lot of built in funct ionalit ies as a suit of product which need t o be developed for ESB im plem ent at ions based on business requirem ent , second m ost propriet ary buses use som e propriet ary form at s t o enhance t he perform ance and t hat increases t he cost . ESB on t he ot her hand is usually st andard based, so it is a t radeoff bet ween perform ance and cost bet ween propriet ary bus and ESB. Main advant age of ESB is t hat it cost s m uch less t hen hub/ spoke or bus based product suit s and t hat it is st andard based.

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CON CLUSI ON

Following t able give a quick com parison of hub/ spoke, bus based product suit s and ESB. Also all t hese t hree archit ect ures can be service orient ed depending on im plem ent at ion which is reflect ed in t his com parison.

Eva lua t ion Pa r a m e t e r

I n st a lla t ion Effor t

Adm in ist r a t ion

Cost

H u b Ar ch it e ct u r e

Less inst allat ion effort com pared t o solut ions wit h bus archit ect ure. Easy t o m aint ain and adm inist rat e because of cent ral hub. High

Bu s Ar ch it e ct u r e Pr opr ie t a r y bu s ba se d pr odu ct su it Moderat e effort

ESB

Adm inist rat ion m ay be com plex depending upon t he int egrat ed syst em s High

Adm inist rat ion m ay be com plex depending upon t he int egrat ed syst em s Low cost because it does not use propriet ary form at s t o enhance perform ance. Also it does not provide all t he services usually provided by propriet ary product suit s.

Moderat e effort

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EAI vs. SOA vs. ESB

Sca la bilit y

St a n da r ds

SOA

High if federat ed archit ect ure is used ot herwise lim it ed by t he hardware of box used t o host Hub Most ly st andard based but m ay use propriet ary int ernal form at s Can be im plem ent ed as service orient ed

Highly scalable

Highly scalable

Most ly st andard based but m ay use propriet ary int ernal form at s Can be im plem ent ed as service orient ed

St andard based

Service orient ed

SOA brings cost effect ive, reusable and low lead t im e solut ions t o an organizat ion but EAI and SOA are bot h going t o coexist . Web services alone as SOA can not handle t he com plex, secure and SLA based applicat ions of an ent erprise current ly and unless we see a t echnological break t hrough it is going t o rem ain t hat way. Ent erprise service bus would enable low cost int egrat ion and would be used by com panies wit h lim it ed I T resources and environm ent s t hat involve a handful of syst em s and m oderat e t ransact ion volum es. Packaged EAI solut ions would have SOA as basic t enet and would cont inue t o be used for large scale int egrat ion by com panies having huge num ber of diverse syst em and high t ransact ion volum es. Next generat ion EAI solut ions would use m ore and m ore of SOA t o provide reliable, secure, low cost and flexible solut ions.

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TAKEAW AYS SUM M ARY 1. SOA brings cost effect ive, reusable and low lead t im e solut ions t o an organizat ion but EAI and SOA are bot h going t o coexist . 2. SOA is m ore t hen web services, in fact web services alone can not handle t he com plex, secure and SLA based applicat ions of an ent erprise. 3. Ent erprise service bus would enable low cost int egrat ion and would be used by com panies wit h lim it ed I T resources 4. Packaged EAI solut ions in fut ure would have SOA as basic t enet and would cont inue t o be t he prim e choice for large scale int egrat ion.

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