This guide provides an overview and description of the Physical Interface Cards (PICs) supported by the Juniper Networks M40 Internet router. The PICs are described alphabetically. Table 1 lists the PICs supported by the M40 Internet router.

PICs provide the physical connection to various network media types. The PICs are mounted on Flexible PIC Concentrators (FPCs), which are inserted into a slot in a router. A PIC occupies a single slot on an FPC. PICs receive incoming packets from the network and transmit outgoing packets to the network. During this process, each PIC performs framing and high-speed signaling for its media type. Before transmitting outgoing data packets, the PICs encapsulate the packets received from the FPCs. Each PIC is equipped with a media-specific ASIC that performs control functions tailored to the PIC's media type. For complete information about installing PICs and transceivers, see the PIC and Transceiver Installation Instructions located at http://www.juniper.net/techpubs/.

Blank PICs resemble other PICs, but do not provide any physical connection or activity. When a slot is not occupied by a PIC, you must insert a blank PIC to fill the empty slot and ensure proper cooling of the system.

A single FPC slot has a maximum throughput of 3.2 Gbps. Inserting a combination of PICs with an aggregate higher than that is supported, but constitutes oversubscription.

Blank PICs resemble other PICs, but do not provide any physical connection or activity. When a slot is not occupied by a PIC, you must insert a blank PIC to fill the empty slot and ensure proper cooling of the system.