X-road offers a way for organisations to talk to each other in a safe and secure manner. However, the challenges presented by two different organisations having to get along are the more pronounced the easier common technical issues are set aside. In this speech some of such problems are highlighted and a collection of integration patterns is introduced seeking to help solve them.

1. Talking to organisations
with x-road
Andres Kütt
Information System Authority, architect
May 22, 2015

2. Introduction

3. Agenda today
• What is architecture?
• X-Road in a nutshell
• Issues in integrating organisations
• Fitting the pieces together

4. What is architecture?
Architecture has many definitions, this speech uses this one:
• Function mapped to form by concept
• Form is what something is
• Function is what that something does
• Concept is how the architect thinks
Function
Form
Concept

5. X-Road in a nutshell
Let’s re-visit the main idea of X-Road
• X-Road is a combination of the following
• Standardized protocol designed for secure and non-repudiable
inter-agency server-to-server communication
• Locally deployable software implementing that procotol
• Centrally deployable software supporting local installations
• Organisational measures allowing the three to function sustainably
• X-Road establishes trust between organisations, each party is
responsible for their own access management
• It is but a communication channel, nothing more and nothing less

6. Issues in integrating
organisations

7. Mapping architectures
Organisations have different architectures, how can we make these talk
to each other?
• Function is taken care of by the actual
services provided
• Form is the domain of x-road:
standards and software
• How do we map concepts?
• Agility vs. stability mindset
• Documents or services?
• What about maturity levels?
Function
Form
Concept

8. Dynamic complexity leakage
Undesirable behavior tends to leak across organisational borders
• Feedback loops appear easily
• Organisation A sees a load spike
• Kills off organisation B
• Unprocessed requests kill off organisation A
• As soon as B recovers, it is swamped again by A
• Awkward behavior on one side can cause irrecoverable awkward
behavior on the other
• Organisation A sees a load spike
• Response time of B drops as parallel sessions grow
• A load spike ends
• Response time of B does not increase as it cannot reduce the
number of parallel sessions

9. An example of dynamic complexity

10. Imperfections of the internet
Modern technology stacks make it easy to forget that internet is
inherently unreliable
• TCP can and will fail, it is inherently asynchronous
• It is not trivial to understand, what and why went wrong
• Did we fail to send a request?
• Did we fail to receive a response?
• It is difficult to maintain transactional integrity across boundaries
• Organisational, application and network boundaries
• HTTP does not compensate for this

11. Handling these issues in x-road
context

12. Looking for a solution
The problems listed are inherently architectural
• They seldom appear as requirements
• Mapping a concept needs to be done so functionality can be
delivered, it is not a requirement per se
• Dynamic leakage might be a non-functional requirement by
operations, if you are lucky
• Very few business folks understand internet enough to think in
terms of “what shall we do if our books do not match at the end of
the month“
• X-road is an element of form and thus cannot provide a solution
Structural problems of one abstraction level can only be solved on the
previous one

13. Structural problems of one abstraction level
can only be solved one abstraction level up

14. Providing tools not solutions
The problem has already been solved. Repeatedly
• Architecture patterns have been in use for decades
• Gang of Four books
• Martin Fowler
• Many others
• The idea: provide a catalogue of standardized approaches to a
standard set of problems
• We need to define all lego pieces needed to build useful things
• Sometimes one still wants to play with clay
• Can we make the pieces small enough to be standardized but big
enough so building stuff would not be tedious?
• The same approach x-road takes: provide a standard solution to a
complex people often get wrong

15. State of affairs as of today
• A set of the lego pieces
• 16 identified at the moment
• Validated to some extent
• Needs to be a living document
• A few of them documented
• Standardised, moderately validated, structure
• Publicly available, in English
• Hard to make a living document: needs to apply to all patterns
• Maintained as a set of LaTeX/palntuml files
• https://github.com/e-gov/xroad-patterns
• Wiki would be more convenient but would add too much overhead
• I happen to like LaTeX and how it fits opensource toolchains

16. Current pattern list

17. The future
Where are we going with this?
• The issues are emergent in Estonia but immediate in Finland
• Because of scale and operational/architecture maturity
• Thus me being here and the text being written in english
• Generate interest
• I’d rather not undertake anything monumental alone
• Or without tangible confirmation of interest
• Work on the documents
• Validate the structure
• Assemble an editorial team
• Start filling in the gaps
• Systematic validation of the content against real life architectures
and existing literature

18. Thank you!
Andres Kütt
andres.kutt@ria.ee