Network switches (also known as a switching hubs, bridging hubs, MAC bridges or simply “switches”) are computer networking devices that connect other devices together in a computer network. Network switches are typically used in complex data networking environments to, for example, interconnect various devices within one or more subnetworks. Some network switches use packet switching to receive, process, and forward data to destination devices. Switches can be used for electrical switching, optical switching that enables signals in optical fibers or integrated optical circuits to be selectively switched from one circuit to another, or a combination of electrical and optical switching.
Typical network switches include a plurality of circuit boards with associated switch circuitry (e.g. line cards and fabric cards) that are interconnected via backplane or midplane circuit boards within an enclosure. Although some cards include handles for manually removing the cards from the enclosure, conventional handles (particularly for optical cards) do not have locking features to hold the cards in place. Additionally, such handles typically require manual manipulation to eject the cards from the enclosure.
As is known, line cards typically include a modular electronic circuit designed to fit on a separate printed circuit board (PCB) and interface with a data communications network, and can provide transmitting/receiving ports for a local area network (LAN) and/or a wide area network (WAN). Fabric cards can include one or more switch elements for implementing the stages of the switch fabric. The line cards and fabric cards can be mounted to the backplane and/or midplane in a motherboard/daughterboard relationship in which the backplane or midplane extends transversely across the enclosure. In this arrangement, the backplane/midplane is perpendicular to the flow of cooling air through the enclosure, and can block or otherwise impede the flow of cooling air, resulting in relatively high operating temperatures that can reduce the longevity and/or performance of switch components. Another factor that can affect cooling is the efficiency of the air inlets and air outlets on the switch enclosure. Conventional network switches utilize fans to move cooling air through the enclosure and maintain the electronic components at suitable operating temperatures. Typically, perforated sheet metal is used to form air inlet and outlet vents on the front and back of the enclosure, respectively. Although such material can provide suitable covers for the enclosure, limitations on the size of the perforations limit the amount of air flow into the enclosure and can result in less than optimum cooling.
In conventional network switches, the central processing units (CPUs) are typically mounted to line cards. As a result, upgrading CPUs in a conventional switch generally requires removal and replacement of line cards to change out the CPUs. CPU technology, however, tends to advance at a relatively quick pace, which can lead to relatively frequent line card removal and replacement for CPU upgrades in conventional switches. In view of the shortcomings associated with conventional network switches, it would be advantageous to develop a network switch that provides, among other things, efficient cooling and relatively easy component replacement.