HP LAN/Switches

Switches come in many different shapes and sizes and can be categorised according to...

• Number of ports - the number of clients and/or servers that can be connected to the switch. Typically switches have between 8 and 48 ports but large Enterprise switches may have several hundred.
• Speed - the throughput of data that the switch can handle. This is measured in 'bits per second' or b/s and typical values are between 10Mb/s (10 million bits per second) and 10Gb/s (10 gigabits per second).
• Physical connections - ports can have various types of physical connection depending on the type of cabling used. Ethernet is the most prevalent office-based cabling standard and typically uses RJ45 connectors and twisted pair, category 5 (CAT5) cable - which supports up to 1Gb/s data transfer speeds. Fibre optic cabling supports up to 10Gb/s and is available in two variants - multi-mode (which operates over distances up to 300 metres) and single-mode (which supports much longer distances).
• Layer - this describes the level of intelligence built into the switch for making decisions on how to route data. Details of the different levels of OSI (Open Systems Interconnection) 7 layer model can be found at http://en.wikipedia.org/wiki/OSI_model but typically switches work at either layer 2 (the 'Data Link' layer) or layer 3 (the 'Network' layer), with layer 3 switches being more efficient at routing traffic around the network.
• Scope - switches are generally designed with one of two scopes in mind. 'Core' switches are deployed at the centre of the Enterprise network, where data throughput, efficiency and resilience are key. 'Core' switches are therefore often used to connect to servers and between different locations. At a departmental level, more cost effective 'Edge' switches are deployed to provide connectivity for clients.

Next: HP Family of Switches