The Cisco CRS 8-Slot Line Card Chassis Enhanced router contains the following components:

• As many as eight modular services cards (MSCs) or forwarding processor (FP) cards (both types are also called line cards), and eight physical layer interface modules (PLIMs). The MSC or FP and PLIM are an associated pair of cards that mate through the chassis midplane. The MSC or FP provides the forwarding engine for Layer 3 routing of user data, and the PLIM provides the physical interface and connectors for the user data.

Each MSC or FP can be associated with several different PLIMs, which provide different interface speeds and technologies. Some of the available PLIMs are:

Note	For a complete list of available PLIMs, consult your Cisco sales representative or visit: http:/​/​www.cisco.com

• • 1-port OC-768c/STM-256c or STS-768 packet-over-SONET (POS). Available with short-reach (SR) optics.
  • 4-port OC-192c/STM-64c or STS-192 POS/DPT. Available with long-reach (LR), intermediate-reach (IR), short-reach (SR), and very-short-reach (VSR) optics.
  • OC-48c/STM-16c or STS-48 POS/DPT, configurable with 1 to 16 ports. Available with long-reach (LR) and short-reach (SR) optics. This PLIM supports pluggable optics.
  • 10-Gigabit Ethernet PLIMs (available with a variety of optics, including LR). These PLIMs support pluggable XENPAK and XFP optics, and can be configured with up to 20 ports, depending on the PLIM.
  • 100-Gigabit Ethernet PLIM. This single-port PLIM supports a pluggable CFP optics module.
  • Cisco CRS SPA Interface Processor-800. Occupies one PLIM slot on the Cisco CRS 8-Slot Line Card Chassis Enhanced router. Supports six normal-height SPAs or three double-height SPAs or any combination in between.
• Chassis midplane. The midplane connects MSCs to their associated PLIMs and allows an MSC to be removed from the chassis without having to disconnect the cables that are attached to the associated PLIM. The midplane distributes power, connects the MSCs to the switch fabric cards, and provides control plane interconnections. The midplane is not field replaceable by the customer.
• One or two route processor cards (RPs). The RPs provide the intelligence of the system by functioning as the LCC system controller and providing route processing. Only one RP is required for system operation. For redundant operation, you can order a second, redundant RP as an option (CRS-8-RP/R). When two RPs are used, only one RP is active at a time. The second RP acts as a “standby” RP, serving as a backup if the active RP fails.

The RP also monitors system alarms and controls the system fans. LEDS on the front panel indicate active alarm conditions.

A Performance Route Processor (PRP) is also available for the Cisco CRS 8-Slot Line Card Chassis Enhanced router. Two PRPs perform the same functions as two RPs, but provide enhanced performance for both route processing and system controller functionality.

Note	A chassis may not be populated with a mix of RP and PRP cards. Both route processor cards should be of the same type (RP or PRP).

• Upper and lower fan trays. The fans pull cool air through the chassis. A removable air filter is located below the PLIM card cage at the front of the chassis. Each fan tray contains four fans.
• Four half-height switch fabric cards (SFCs). These cards provide the three-stage Benes switch fabric (S1/S2/S3) for the routing system. The switch fabric performs the cross-connect function of the routing system, connecting every MSC (and its associated PLIM) with every other MSC (and its associated PLIM) in the system.

The switch fabric receives user data from one MSC (or FP) and PLIM pair and performs the switching necessary to route the data to the appropriate egress MSC (or FP) and PLIM pair. The switch fabric is divided into eight planes that evenly distribute the traffic across the switch fabric. Each switch fabric card implements two planes of the switch fabric.

• A power system that provides redundant power to the chassis. Two types of power systems are available: either AC or DC power. The modular configuration power solution contains two power shelves with either up to four DC power modules (PMs) or up to three AC PMs per power shelf.

The PLIM side of the chassis is considered the front of the chassis, where user data cables attach to the PLIMs and cool air enters the chassis. The MSC side, which is where warm air is exhausted, is considered the rear of the chassis.

This section identifies the location and slot numbers for major cards and modules (primarily the field-replaceable units) that plug into the chassis.

The following figure shows the slot numbers on the front (PLIM) side of the Cisco CRS 8-Slot Line Card Chassis Enhanced router.

Figure 3. Cisco CRS 8-Slot Line Card Chassis Enhanced Router Slot Numbers—Front (PLIM) Side

As shown, the front (PLIM) side of the chassis has the following card slots:

• Eight PLIM slots (left to right: 0, 1, 2, 3...4, 5, 6, 7)
• Two route processor card slots (RP0 and RP1)

The following figure shows the slot numbers on the rear (MSC) of the chassis.

Figure 4. Cisco CRS 8-Slot Line Card Chassis Enhanced Router Slot Numbers—Rear (MSC) Side

The rear (MSC) side of the chassis has the following card slots:

• Eight MSC slots (left to right: 7, 6, 5, 4...3, 2, 1, 0)
• Four half-height switch fabric card slots (SM0, SM1, SM2, and SM3)

The MSC slot numbers are reversed from the PLIM slot numbers on the other side of the chassis. Because an MSC mates with its associated PLIM through the midplane, MSC slot 0 is on the far right side of the chassis looking at it from the rear (MSC) side.

PLIM slot 0 is on the far left side of the chassis, looking at if from the front (PLIM) side. MSC slot 0 and PLIM slot 0 mate with each other through the midplane, and so do all other MSC and PLIM slots (0 through 7).