A [device] or [system] which can [forward] [IP] [packet]s at [layer 3] and often posses functionality to switch packets at [layer 2] as well. An IP switch uses mechanisms to [classify] which packets will be forwarded at [layer 3] and which will be switched at [layer 2] and then redirect some or all packets over a [layer 2] [switched path]. Most IP switches utilize an [ATM] [switching fabric], but other [technologies] can be used as well.

IP switches are useful as they only utilize the [bandwidth] needed for a packet on a single [interface]. This is not like a [layer 1] [ethernet] [hub] or [repeater] switch rebroadcasts each packet out on all interfaces. IP switches are more useful than [layer 2] switches because they need not rely on the underlying [layer 2] [protocol] to switch IP. You can switch a packet from a [ATM] interface to a [frame relay] interface just as easily. IP switches are often put at the [core]s of large networks for these very properties.

Manufacturers of IP switches include [Cisco], [Juniper], and [Extreme Networks]. There are scores of other smaller players in this market. Many of the successful ones can switch IP packets at [wire speed].

[MPLS], or [Multiprotocol Label Switching], is a technology which is slowly but surely creeping into this market segment. [MPLS] switches operate inbetween [layer 2] and [layer 3] to operate and are protocol independent.

ip switch