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Figure 11 – Bank of batteries
2.1.1.6 Network infrastructure

Communications in data centers today are most often based on networks running the IP protocol
suite. Data centers contain a set of routers and switches that transport traffic between the servers
and to the outside world. Redundancy of the Internet connection is often provided by using two or
more upstream service providers as Multihoming. Multihoming refers to a computer or device
connected to more than one computer network. It can be used, for example, to increase the
reliability of an Internet Protocol network, such as a user served by more than one Internet service
provider. Also SAN solutions are recommended for redundant storage management.
Some of the servers at the data center are used for running the basic internet and intranet services
needed by internal users in the organization, e.g., e‐mail servers, proxy servers, and DNS servers.

Network security elements are also usually deployed: firewalls, VPN gateways, intrusion detection
systems, IPS (Intrusion Prevention System) is also widely used. Monitoring systems for the network
and some of the applications are also common. Additional off site monitoring systems are also
typical, in case of a failure of communications inside the data center.

230 ITU‐T's Technical Reports and Specifications