Cloud concepts
Multi-Tier network
This is an example of a multi-tier network:
The web servers are in an isolated network that, in technical jargon, is called a DMZ (DeMilitarized Zone). Its aim is that the servers that are in direct contact with the outside world arrive in this zone.
This network is protected by a double firewall, one between the Internet and the internal network and the other one between the internal network and the underlying database and application servers. This way, there is a protection at 2 different levels.
Private Backend
This is an example of a network that acts as an extension of the customer's back-office. This network usually contains Exchange servers, SharePoint servers, Active Directory servers and file servers.
In principle, this is possible with public cloud and private cloud.
Private Hybrid cloud
This is an example of a private hybrid cloud: Here, we will combine a private cloud with an SQL cluster based on dedicated hardware. This is ideal with databases with extremely heavy loads. For such heavy applications, virtualisation is not always the best solution.
Thanks to the clustering technology, both nodes are actively used and high availability is also guaranteed.
Multi-data centre cloud (multi-cloud)
In this scenario, we will spread the platform over 2 different sites. Firewalling and load balancing are also redundantly spread over both data centres. Here, the resources from both sites can always be used.
If a disaster happens in 1 of both data centres, the other data centre will temporarily process all the traffic.
