The Hong Kong guide to the Paris guide to IT infrastructure

There are many metaphors for enterprise architecture. The most common one I've heard is that enterprise architects are the glue between an organisation's strategy and execution. This reads well as a LinkedIn status update or tweet, but you could say the same about project managers responsible for executing strategic projects, or CFOs who pick strategic projects and ensure they're funded. Whenever someone asks for my view on the role of enterprise architects, I like to say I'm a student of the "Paris" school of enterprise architecture.

The Paris Guide to IT architecture was an article published in the McKinsey Quarterly in 2000. It talks about the history of Paris and how the city's architecture and buildings have a consistent feel and theme despite architects who've had over 200 years to "improve" it. The consistency of Paris is used as a metaphor for IT architecture: just as the roads and public transport of Paris unite the buildings, define the landscape and set the terms for evolution (Laartz, 2000), enterprise architecture involves the systems and frameworks that unite applications and provide a way of integrating and accommodating disparate systems in a coherent way. Although it doesn't say it, the article hints that enterprise architects are the town planners of IT. I've never visited Paris, but the concept resonates when I compare Hong Kong or Singapore to lesser planned cities in Asia.

The IFC check-in service in Hong Kong strikes me as an example of a system that exists because other systems have been architected well. The Hong Kong International Airport (HKIA) allows you to check-in to your flight and drop your bags in the city, leaving you with a boarding pass and the opportunity to spend your day shopping and exploring the city instead of waiting in an airport lounge surrounded by stereotypes. While you do your shopping, your bags are securely transported to the airport, saving you the stress of carrying them or having to stop at your hotel before the airport.

International Finance Center (IFC): the building Batman jumps from in The Dark Knight.

The architecture for IFC check-in relies on the availability and openness of other systems like

• airline systems, to facilitate check-in at IFC.
• airport systems, to provide airport services including security, timetabling, messaging, alerting.
• the Airport Express rail system which provides mass transit from IFC (or any station) to HKIA
• luggage transport systems that move traveller luggage securely from IFC to the airport and provide handoff to the airport luggage routing system
• network systems, to facilitate secure and reliable communication with the airport
• et cetera

The actual specifics behind system integration isn't enterprise architecture: that's application architecture. The fact the required functionality and systems were available was because of enterprise architecture. During the architecture of the baggage system, the application and infrastructure architects may have developed the best solution for accepting baggage from an on-premise airline check-in desk and delivering it to a plane. But was their solution service-oriented? Was it open? How flexible would the solution be if a new requirement for bag drop from off-premise sources (such as the IFC check-in) was introduced? Or if bag drop from hotels was introduced? Upfront completeness of requirements is important, but part of enterprise architecture is knowing when to keep the door open and how to do it.

A town planner might know that every premise requires lines for sewage, electricity, water, gas and telephone, but they still might keep the door open for future services by requiring ducting infrastructure from streets to the home. If a new technology came along to replace copper telephone lines, existing ducting infrastructure would make the job a heck of a lot easier. And like in the real world, if you don't think ahead, rectification could either be costly or impossible.