In order to transform our legacy IT architecture with monolithic applications, into the digital world new DPSs - digital platform services with associated microservices, each covering well defined business capability, are required. This approach will help us not only to develop independently, but also to fix the accountability, and scale granularly. The microservices will be integrate with the Telco BSS/OSS systems through HAL-Harmonized Application Layer – common standard for new API based on TMForum Open API principles. Common governance over DPS/microservices and HAL is essential to establish flexible, scalable and 'always on' architecture and to support speedy business deliveries.

1. We change our orientation to new, microservice
architecture with DPS andHAL.
Good decision?
VjekoslavAleksić &DominikPeriškić
ShiftDev conference, Split

2. CROATIANTELECOM GROUP OVERVIEW
LEADING TELCO GROUP IN CROATIA

3. CROATIANTELECOM GROUP OVERVIEW
Weare themarketleader,providing
full rangeof telecommunications
services,fixedlineand mobile
telephoneservices,data
transmission,internetand
internationalcommunications.

4. OURSTORY OF IT TRANSFORMATION…

5. TELCO
+
BIGNICE ENTERPRISE IT SOLUTIONS
HOWIT ALL STARTED…

6. „…thatlicencecostsare waytoomuch…”
…BUT ‘CERTAIN’ PROBLEMS BEGAN…
„…lastchangeonreportmake passwordresetnotworkinganymore.Whhhhy?”
„…whyisitsodifficulttoadda newfeature?”
„…no,no,slowapplicationisnotopportunityforsocialtalkandnewsale …”
„…whyIcan’tjustaddnewserverandsolvethatperformances?”
„…youaresayingthatifremove inventory,billingwon’tworkanymore?”
„…whydoyouneedthreedaystopreparea patch?”
„…whyI can’tuseexistingintegrationformynewPortal?”

7. …SO THEREWAS SOME THINKING…

8. …AND SOME SOLUTIONS…
DPS & microservices
HarmonizedApplication Layer (HAL)
DevOps
OpenSource
Continuousintegration
OR‘SOLUTIONS’? WE’LL SEE…

9. DIGITAL PLATFORM SERVICES
Business view
 Covers a small “Bounded business
Context”
 Self-contained (tolerant against failure):
 independently designed , developed,
deployable and scalable
 Easy to understand and modify
 Developed and operated by a small
focused team
IT view
 Each service has its own database in
order to be decoupled from other
services
 Stateless communication/interaction,
e.g. through Restful APIs provided by
each microservice.
 easily scalable in horizontal and vertical
manner
 Microservices are easily replicable or
upgradable with (semi-) automated
CI/CD procedures

10. DIGITAL PLATFORM SERVICES – WE HAVE CREATED SOME
Customer Hub
Customer master data
(party, customer,
accounts)
Subscription mng
Customer product
inventory with CFS and
BFS data
Order execution
Decomposition,
enrichment, distribution
and orchestration
orders.
Commercial Product
Catalogue
Product specifications,
offers, prices, rules and
relations
Order Capture
Order entry, validation
and establishment
Order tracker
Tracking customer
order from submit to
the end
Order document
management
Document template and
creation
Shipment management
generate delivery
orders to shipment
vendors and tracking
the delivery status

11. DIGITAL PLATFORM SERVICES – TECHNOLOGY STACK

12. OURDEVOPS PIPELINE

13. OURDEVOPS PIPELINE- DEMO
Codeis created in InteliJ
Codecommited toGitLab
Built andpackaged in Jenkins
Quality check with SonarQube
Deployed toNexus repository
Deployed toOpenShift test
environment
Deployed toOpenShift System
integration test environment

14. …NEWAPPROACHCHALLENGES…
Lotsofopensourcesolutions
Newtechnologies,notmuchreferences intelco
Onlybasicinternalknowledge
Notlarge servicesupportoptions
Manyresearchesbeforedevelopment
Complexintegrationstosupportbusinessprocesses
…and thatswhereHAL comes…

15. HAL–
HARMONISEDAPILAYER -Data model, business rules, caching,
optimization…
BACKEND
Dashboard
API
Services
API
Billing
API
Faults
API
PRP recharge
API
Store
locator API
15
MICROSERVICEARCHITECTURE DWH
BigData
TRANSITION FROM MONOLITHS TO MICROSERVICES
LEGACYSTACK

16. API STRATEGY BASED ON ”API FIRST” APPROACH
CLIENT
Dashboard,Services,Billing,Faults,PRPrecharge,Storelocator…
MIDDLEWARE
Datamodel,businessrules,caching,optimization…
* LA = Local Adapter, BE = Backend
DESIGN APIS BASED ON REQUIREMENTS,NOT BASED ON CURRENTINFRASTRUCTUREANDDATA MODELS
BACKEND
CRM,Billing,FR/PRTicketing…
API 1 API 2 API 3 API 4 API 5 API 6
IT BE NT BE
L
A
L
A
L
A
L
A
L
A
L
A
API LAYERREST APIs
START HERE
(outside-in)
NOT HERE
(not inside-out)

17. HAL CONTEXT LOGICAL ARCHITECTURE
Layer 1
Layer 2

18. HAL RELEASE CYCLES – AGILE, SHORT AND EFFICIENT
10 days NatCo
development*
5 days
demand
consolidati
on &
planning
5 days
HAL API
spec.
5 days
HAL API
review
10 days integration
testing
and adding regression
test capability
10 days FE
development
…
Central HAL team
NatCo
FE = Frontend
WF = Wireframe
API approvals by all NatCos at same time! (GR to be on-boarded yet)
Only 15 days for new API definitions!
New functionality delivered every 2 weeks!*
Massive changes enabled via multi-sprint approach!
NatCo development might depend on business decision, but API review/approval to be done by all N
Client/FE
NEW APPROVED API VERSIONS!
Final API documentation and
mocking services available!
aligned
deman
d
* Assuming that NatCo backend functionality is in place and NatCos follow HAL API sprint cycles.
aligned
deman
d
HALdemand
board
10 days NatCo
development*5 days HAL
API spec.
10 days integration
testing
and adding regression
test capability
10 days FE
development
HALdemand
board
aligned
deman
d
10 days NatCo
development*5 days HAL
API spec. 10 days FE
development
HALdemand
board
HALdemand
board
HALdemand
board
HALdemand
board
HALdemand
board
HALdemand
board
HALdemand
board
Central business
5 days
demand
consolidati
on &
planning
5 days
demand
consolidati
on &
planning
5 days
HAL API
review
5 days
HAL API
review

19. PROCESS:HOWTO DEAL WITHNEW DEMANDS
HAL
API
existing
?
TMF
Open
API
existing
Extend existing
HAL API to cover
new demand
Other
API
standar
ds
usable?
Create new HAL
API based on TMF
Open API
specification
Create new HAL
API based on found
usable standard
Get famous and
define a new HAL
API from scratch.
yesno
yes
yesno
no

20. HAL SPRINTDELIVERIES
Swaggerfiles
Sequence
diagrams
Examples
Postman
collection

21. COLLABORATION TOOLS USED IN CENTRAL PROGRAMS
Confluence
Jira
Git – HAL
Core
Slack

22. TEAMWORK - AGILE
Workshop
in
Budapest
Working
on ping-
pong
table
Great
things in
business
are never
done by
one
person.
They are
done by a
team of
people. –
Steve Jobs
Working
in teams
On the
road
Teamwork
at it’s fullest
Navigat
or
Driver
Working
while
traveling

23. RECOGNITIONS
Inovation Award for OneApp program
TMF Excellence Award Nominations:
 Open API Award
 IT transformation Award

24. OURCONCLUSION…FORNOW
Don’tgiveup(wehada lotofdrinkswiththoughts„weshouldbuySiebel“)
So,althoughwe hadandstillwillhavea lotofchallengesinourway…
StandardisedDevopsprocessandintegrationisessential
Collaborationwithbussinessisa key
Monitor,adoptandchangeallthetime
Trustyourteamandmake themtrustyou
…we continueour microservice path…
It works

25. THANK YOU!