Chapter 3 Advanced Routing : Intermediate System to Intermediate System Protocol (IS-IS) : Simple IS-IS example : Network layout and assumptions
  
Network layout and assumptions
It is assumed that each FortiGate is operating in NAT mode, running FortiOS 4.0MR2+.
All interfaces have been previously assigned and no static routes are required.
The AFI (Authority and Format Identifier) used is 49 : Locally administered (private).
The Area identifiers are 0048 and 0049.