Thank you Karstenl for sharing this.
I particularly like Option 6: Two MX, two ISPs (4), which ensures that there is a backup for each component (FAI, Switch and MX)
Pros:
- redundancy and reliability.
- minimum single point of failure.
Cons:
- Requires physical intervention if a switch fails, as the ISP connection needs to be moved manually from the damaged switch to the working one.
- Having two links from the ISP is not common and may not be feasible for all setups.
Despite these potential drawbacks, I believe the added redundancy makes this option the best choice.