1. On the drawing is the network logical diagram of a mission critical production infrastructure.

The key features are:
- High network and server availability;
- High security;
- 1Gb interconnections between the tiers;
- Segregation between production and server interconnection traffic;
- Separated management and monitoring networks;
- Out of bandwidth remote administration.
Centralized fibre-channel storage (SAN)

This is the tipical 3 tears production infrastructure I would usualy designe for mision criticle busineses.

For more drowings and details click over the picture or here