R&M Data Center Handbook

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Storage Solutions
The demand for storage capacities has been steadily growing as
a result of increasing volumes of data as well as require-ments
for data backup and archiving. Cost efficiency in the area of
company storage is therefore still a central theme for IT
managers. Their goal is to achieve high storage efficiency by
using their existing means and hardware in combination with
storage virtualization, Cloud Storage (Storage as a Service) and
consolidation.
The popularity of the Unified Storage approach, a system that
supports all storage protocols, has been picking up speed in
new storage acquisitions.
Racks that contain only hard disks are finding their way into more and more data centers and are being supplied
preassembled by solution providers such as:
• NetApp • EMC • HDS Hitachi Data Systems
• HP • IBM • Oracle (Sun Microsystems)
Secondary storage solutions like jukeboxes and tape backup systems no longer play a part in current storage
solutions. However, IT managers must not ignore the conventional backup as well as data storage that is legally
required – key word compliance – for all the storage technologies they use.
3.6.3. Network Infrastructure Basics (NICs, Switches, Routers & Firewalls)
Networks can be classified in different ways and through the use of different criteria. A basic distinction is made
between private (LAN) and public (WAN) networks, which also use different transmission technologies. One
typically comes across base-band networks in LANs (Ethernet, and also Token Ring and FDDI in earlier times)
and broadband networks in WANs (ATM, xDSL, etc.). Routers which possess a LAN interface as well as a WAN
port assume the task of LAN/WAN communication transition. The Ethernet is also definitely pushing its way more
and more to the front of technologies for public networks, as a result of its continuing development and easy
implementation, particularly for providers who operate city-wide networks (MANs).
The components in a network infrastructure can basically be divided up into two groups:
• Passive network components which provide the physical network structure, such as cables (copper and
glass fiber), outlets, distribution panels, cabinets, etc.
• Active network components, which process and forward (amplify, convert, distribute, filter, etc.) data.
The following sections cover active network components in detail, to give an understanding of their function and
area of application.
NIC – Network Interface Card
A network interface card (NIC) usually exists “onboard” a network-compatible device and creates the physical
connection to the network, by means of an appropriate access method. Ethernet in all its forms (different media
and speeds) is currently being used almost exclusively as an access method, also known as a MAC protocol
(Media Access Control).
Each NIC has a unique hardware address, also called a MAC address, that is required by switches in order to
forward Ethernet frames. The first 3 bytes of this 6-byte MAC address is assigned by IEEE for the manufacturer,
who uses the remaining 3 bytes as a serial number.
Therefore, in addition to its configured IP address which is required for routing, every device integrated in an
Ethernet LAN also possesses a MAC address, which is used by switches for forwarding.
Repeaters and Hubs
These network components are not used much today, since, for reasons of performance, current LAN networks
are constructed only to be switched. They were used as signal amplifiers (repeater) and distributors (hub) in
shared Ethernets in which network subscribers still had to share overall bandwidth. Since these devices are rarely
used today, we will omit a detailed description of them.
Page 84 of 156 © 08/2011 Reichle & De-Massari AG R&M Data Center Handbook V2.0