Scaled Agile Framework is BASED on Agile Architecture which APPLIES to all the levels in SAFE. It has few set of principles which helps to maintain the overall strength of the process/model:

• Design emerges. Architecture is a collaboration. 
• The bigger the system, the longer the runway. 
• Build the simplest architecture that can possibly work. 
• When in doubt, code or model it out. 
• They build it. They test it. 
• There is no monopoly on innovation. 
• Implement architectural flow.

Agile architecture allows incremental value delivery by harmonizing emergent design and intended architecture: 

“By balancing emergent design and intentionality, Agile architecture is a Lean-Agile approach to addressing the complexity of building enterprise Solutions. In TURN, this approach supports the needs of current users while simultaneously evolving the system to meet near-term future needs. Used together, emergent design and intentionality continuously build and extend the Architectural Runway that provides the TECHNICAL foundation for future development of business value.” – scaledagileframework.com