What is Cisco Chassis, Backplane, and Line Card?Chassis, You Know Here:A Chassis is a frame/housing for mounting the circuit components for Cisco Switchesand Routers or any type of devices that provides power and a high-speed backplane.The frame also protects all of the vital internal equipment from dust, moisture, andtampering.Making the Chassis to define even easier is;A chassis is an enclosure; a container that holds things together... i.e. an egg cartonholds eggs together inside. A chassis does the same thing; it holds the importantthings inside like wiring, power supplies etc. Cisco Chassis Cisco BackplaneGeneral info of BackplaneBackplane is a circuit board with sockets that allows Supervisor engines Cards ormodules to be inserted into these sockets and connect them to each other.Backplane is mounted on the Chassis.Modules or line cards provide different types of interfaces, but the processing ofpackets is usually done in the Supervisor engine. Backplane is the medium for dataflow between modules and Supervisor engines.Additionally, most high-end switches off-load processing away from the supervisors,
allowing line cards to switch traffic directly between ports on the same card withoutusing any processing power or even touching the backplane. Naturally, this cant bedone for all traffic, but basic layer-2 switching can usually be handled exclusively bythe line card, and in many cases also more complex operations can be handled aswell.What is Line Card?The line cards provide interfaces to the network.A line card can terminate a line supporting voice POTS service, ISDN service, DSLservice, or proprietary ones. Some line cards are capable of terminating more thanone type of service.Since an access network element is usually intended to interface many users(typically a few thousands) some exchanges have multiple line terminations per card.Similarly, it is common to have many line cards in the same network element.A line card or Digital Line Card is a modular electronic circuit on a printed circuitboard, the electronic circuits on the card interfacing the telecommunication linescoming from the subscribers (such as copper wire or optical fibers) to the rest of thetelecommunications access network.A line card commonly interfaces the twisted pair cable of a POTS local loop to thepublic switched telephone network (PSTN). Telephone line cards used in PSTNperform multiple tasks such as analog-to-digital and digital-to-analog conversion ofvoice, off-hook detection, ring supervision, line integrity tests, and other BORSCHTfunctions. In some telephone exchange designs the line cards generate ringingcurrent and decode DTMF signals. The line card in a Subscriber Loop Carrier iscommonly called a Subscriber Line Interface Card (SLIC).