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Table of Contents

Product Overview

Product Overview

This chapter presents an overview of the Cisco 12008 Gigabit Switch Router.

The following sections are included in this chapter:

Cisco's Next Generation of Routers

Cisco Systems' new family of Internet switching and routing products, referred to collectively as the Cisco 12000 Series Gigabit Switch Routers, consists of the following models:

The architecture of the Cisco 12000 Series Gigabit Switch Routers provides the following networking capabilities and features:

The network interfaces reside on these line cards, providing connectivity between the router's switch fabric and external networks.

The networking capabilities and features of the Cisco 12000 series of routers make them ideally suited to meet the needs of the following classes of users:

Features of the Cisco 12008 Router

The Cisco 12008 router incorporates a high-speed switching fabric that provides high data-handling capacities for IP-based local- and wide-area networks. Figure 1-1 is a front view of the Cisco 12008 router.

All of the router's major components and FRUs are accessible from the front of the router enclosure, making the router easy to install, configure, and maintain.


Figure 1-1: Cisco 12008 Gigabit Switch Router



The Cisco 12008 supports the following features:

Note The Cisco 12008 does not support a mixture of AC-input and DC-input power supplies.
Separately orderable documents called configuration notes or replacement instructions are available for each of the FRUs described previously. These documents provide installation, removal, replacement, and configuration instructions for the FRUs.
MBus software running in the GRP, in combination with LEDs on the CSC faceplate, keep site personnel informed regarding the operational state of the router.
By signaling alarm conditions, such as component overheating or out-of-tolerance voltages, the router enables you to resolve adverse environmental conditions before operational limits are exceeded, thus preventing the router from shutting down.
The MBus facility of the router is described in greater detail in the section entitled "Cisco 12008 Environmental Monitoring Facility" on page 64.

Overview of the Cisco 12008

The Cisco 12008 is a modular system consisting of the elements shown in Figure 1-2.

The following sections describe the major elements of the Cisco 12008 in greater detail.


Figure 1-2: Major Components of the Cisco 12008



Router Enclosure

The outer shell of the Cisco 12008 is a rigid, sheet metal structure with the following dimensions:

This enclosure, which houses all of the router's internal components, can be mounted in a telco rack or a four-post equipment rack, or the enclosure can be used as a freestanding unit.

The design of the enclosure permits front accessibility of all router components. All router components plug into a backplane that provides operating power for the components and interconnects them with each other.

The backplane, which is covered by a sheet metal panel that helps to completely enclose the rear of the router, incorporates a nonvolatile random access memory (NVRAM) module that stores the backplane serial number for identification and revision control purposes. The contents of the NVRAM module are accessible from any line card slot.

Cable-Management System

The cable-management system provides an orderly and convenient way for you to manage the network interface cables running to and from the receive and transmit ports of installed line cards.

Consisting of a cable-management tray and a vertical cable-management bracket (one bracket for each installed line card), the cable-management system (see Figure 1-3) secures the network interface cables neatly in place. The cable management system helps to optimize optical cable performance by eliminating any kinks or sharp bends in the cables. Extreme curvatures in optical cables tend to degrade their performance.

The elements of the cable-management system are shown in Figure 1-3 and described briefly in the following sections:

The cable management tray enables you to route the line card interface cables to or from the system through the left side of the tray, keeping the cables organized, out of the way, and free of kinks or sharp bends.
You direct the cables down to the individual ports on each line card, gauging cable length appropriately to minimize slack in the cable before connecting it to a given port.

Figure 1-3: Cable-Management System



Once an interface cable is connected to its intended line card port, you loop the cable through the cable keeper clip nearest the port of connection and seat the cable in the bottom of the bracket raceway.
Thus, the vertical cable-management bracket enables you to neatly "dress" all the interface cables in place as you connect them to the individual line card ports.
Later, when you remove or replace a line card, you need only disconnect the cables from the individual line card ports (leaving the cables intact within the vertical cable-management bracket) and detach the bracket from the line card to be replaced.
When you install the new line card, you merely reattach the vertical cable-management bracket to the new line card and reconnect the interface cables to the appropriate line card port(s).

Card Cage Fan Tray

The card cage fan tray is located in the lower card cage behind the air filter assembly (see Figure 1-2). This fan tray maintains the operating temperature of the router's electronic circuitry within an acceptable range.

Designed for simplicity, the card cage fan tray incorporates six fans mounted on a sheet metal carrier. The assembly also contains associated wiring and a connector in the back of the unit that enables it to draw operating power through the backplane from a DC-DC converter on the CSC.

Guide rails in the sides of the lower card cage facilitate insertion and removal of the fan tray assembly, which is secured in place by means of a captive installation screw on each side of the metal carrier.

Under normal operating conditions, the variable-speed fans in the card cage fan tray operate at a reduced rate to

If an overtemperature condition or a fan failure is detected within the router, the master MBus module on the GRP directs the MBus module on the clock and scheduler card (CSC) to increase the operating voltage being delivered to the fan tray, causing the card cage fans to run at "maximum" speed. This increases the volume of cooling air flowing through the router.

If the increased fan speed does not alleviate the overtemperature condition in the affected board, the MBus module on the board shuts down the board's power supply, taking the board offline to protect it from thermal damage.

The MBus facility of the Cisco 12008 router is described in greater detail in the section entitled "Cisco 12008 Environmental Monitoring Facility" on page 64.

Power Supply Fan Tray

The power supply fan tray is in the bottom of the power supply bays (see Figure 1-2). This fan tray maintains the temperature of the installed power supply(ies) within an acceptable range.

Also designed for simplicity, the power supply fan tray incorporates four fans mounted on a sheet metal carrier. The fan tray assembly contains associated wiring and a connector in the back of the unit that enables it to draw operating power through the backplane from a DC-DC converter on the CSC.

A captive installation screw mounted on the fan tray faceplate and guide rails in the sides of the power supply bay facilitate insertion and removal of the unit. Once the unit is inserted, you secure it in place by tightening the captive installation screw clockwise.

Similar to the card cage fan tray, the power supply fan tray is closely tied to the router's overall environmental monitoring system. If an overheating condition or a fan failure is detected within the router, the voltage being delivered to the power supply fans by the CSC is also increased, thereby causing the power supply fans to run at "maximum speed" to increase the volume of cooling passing through the power supply bays.

AC-Input and DC-Input Power Supplies

The Cisco 12008 router can be configured to operate with AC source power or DC source power. You can install one or two AC-input power supplies or one or two DC-input power supplies in the power supply bays located in the right side of the router enclosure (see Figure 1-2).

A single power supply of either type is the standard router configuration. In such a configuration, it is recommended that you install the power supply in the lower bay.

You can install a second (optional and redundant) power supply of the same type for backup purposes.

Caution A vacant power supply bay must be covered with a blank filler panel to ensure proper flow of cooling air through the power supply bays and to satisfy EMI compliance requirements.
Note You cannot use an AC-input power supply in conjunction with a DC-input power supply. Installed power supplies must always be of the same type. Furthermore, you should not install two power supplies of either type unless you intend to actively use both units. In other words, you should not power the router with a single power supply while using the other bay to temporarily or indefinitely "store" an inert unit. Doing so will disrupt the normal flow of cooling air through the router enclosure.

Figure 1-4 shows an AC-input power supply; Figure 1-5 shows a DC-input power supply.


Figure 1-4: AC-Input Power Supply




Figure 1-5: DC-Input Power Supply



Operating Modes of the Power Supplies

The AC-input and DC-input power supplies operate in either of two modes:

The online insertion and removal (OIR) capability of the router enables you to add or remove a redundant power supply without introducing noise in the DC operating voltages being supplied to the backplane.

Features of the Power Supplies

The AC-input and DC-input power supplies incorporate the following features:

The environmental monitoring system includes identical MBus modules on all of the router circuit boards, including the GRP. This system enables you to perform router functions and to respond to alarm conditions (such as overtemperature or overvoltage conditions).
An alarm condition in the router causes the MBus module on the CSC to illuminate an appropriate LED on the card faceplate, providing a visible notification of the alarm condition.

Characteristics of the Power Supplies

The AC-input and the DC-input power supplies have the following characteristics:

AC-Input Power Supply Faceplate

This section describes the functional elements built into the faceplate of the AC-input power supply (see Figure 1-6).


Figure 1-6: AC-Input Power Supply Faceplate



Rotary Power Switch

The rotary power switch on the power supply faceplate (see Figure 1-6) applies a source AC voltage to the power supply. This switch also actuates an onboard circuit breaker and a latching mechanism that prevents the power supply from being inserted into or removed from the power supply bay when the switch is in the ON (1) position.

When you rotate the rotary power switch 90 degrees to the ON position, the following DC operating voltages are supplied to the backplane:

Source AC Input Connector

The source AC receptacle on the power supply faceplate (see Figure 1-6) enables an external AC power source to be connected to the power supply. This connector is equipped with a latch that prevents accidental or unintended removal of the AC power cord.

The power specifications for the AC-input power supplies, as well as the source AC power cables available for use with the Cisco 12008 router, are described in Chapter 2 in the section entitled "AC-Powered Systems."

AC-Input Power Supply LEDs

The AC-input power supply faceplate incorporates two LEDs (see Figure 1-6) that provide the following status indications:

DC-Input Power Supply Faceplate

This section describes the functional elements built into the faceplate of the DC-input power supply (see Figure 1-7).


Figure 1-7: DC-Input Power Supply Faceplate

Rotary Power Switch

The rotary power switch on the DC-input power supply performs the same functions as those described in the section entitled "Rotary Power Switch" on page 18 for the AC-input power supply.

Circuit Breaker Alarm Terminal Block

The onboard power supply circuit breaker actuated by the rotary power switch on the DC-input power supply incorporates an auxiliary switch that is mechanically linked to (but electrically isolated from) the power supply circuit breaker.

When the power supply circuit breaker is tripped by an overcurrent condition in the power supply, this auxiliary switch moves in unison, sending a signal to the circuit breaker alarm terminal block on the power supply faceplate (see Figure 1-7).

To remotely sense when the power supply circuit breaker has been tripped during an overcurrent condition, you can attach an external alarm-monitoring facility to the alarm terminal block. When the power supply circuit breaker is tripped, power is no longer delivered to the backplane and the router ceases to operate. Hence, if you have attached an external alarm monitoring facility to the alarm terminal block, site personnel can be instantly alerted to this serious fault condition.

Typically, an external alarm-monitoring system incorporates a light panel (visible alarm) or a klaxon (audible alarm) as the means for alerting site personnel to an alarm condition.

To reset the alarm contacts on the alarm terminal block, you must turn the rotary power switch on the power supply OFF and then ON again, much as you would reset any circuit breaker.

Note Any time you manually actuate the rotary power switch, such as when powering down the router, the contacts on the alarm terminal block remain unaffected. Hence, activation of the contacts on the alarm terminal block occurs only during a power supply overcurrent condition. In other words, these contacts are used to provide an immediate, overt indication of a power supply fault condition; they are not used to merely indicate that a circuit breaker has been turned off manually.

The three contacts on the alarm terminal block are labeled as follows:

Table 1-1 summarizes the status of the contacts on the alarm terminal block during an overcurrent condition in the power supply.


Table  1-1: Circuit Breaker Status Indicated by the Alarm Terminal Block
Circuit Breaker Position NC Contact NO Contact
OFF (tripped) Open Closed
ON Closed Open

If you decide to use an external alarm-monitoring facility in conjunction with the alarm terminal block, note that the contacts on the alarm terminal block have a rating of 60 VDC at 1A maximum.
Source DC Input Connectors

The faceplate of the DC-input power supply incorporates three sets of terminals for connecting source DC power to the power supply (see Figure 1-7). From top to bottom, these terminals are identified as follows:

The power specifications for the DC-input power supplies, as well as the specifications of the source DC power cables for use with the Cisco 12008 router, are presented in the section entitled "DC-Powered Systems" on page 16 in Chapter 2.

DC-Input Power Supply LEDs

The DC-input power supply faceplate incorporates two LEDs (see Figure 1-7) that provide the following status indications:

Upper Card Cage and Associated Components

The upper card cage (see Figure 1-8) contains ten slots that accommodate the following types of cards in the quantities indicated:

Two dedicated slots in the middle of the upper card cage (CSC0 and CSC1) are reserved for the CSCs. Because the backplane connector of a CSC differs significantly from all other card types, you cannot install a CSC in any other slot.
Although you can install a line card in slot 0, the recommended convention is for the GRP to occupy this slot.

Figure 1-8: Upper Card Cage of the Cisco 12008 Router



A minimally configured Cisco 12008 contains the following cards in the upper card cage:

A Cisco 12008 that is configured for full redundancy contains the following cards in the upper card cage:

The following sections briefly describe the cards that you can use to populate the upper card cage.

Gigabit Route Processor

The Gigabit Route Processor (GRP) is a high-performance circuit board that serves as the main system processor for the Cisco 12008.

This section describes the following facilities, which are built into the GRP:

The faceplate of the GRP is shown in Figure 1-9.


Figure 1-9: GRP Faceplate (Horizontal Orientation Shown)



It is recommended that you install the GRP in the left-most slot (slot 0) in the upper card cage. However, you need not abide by this recommendation. You can install the GRP in any upper card cage slot, except for the two slots in the middle in the upper card cage (CSC0 and CSC1), which are reserved for the CSCs.

The GRP performs the following functions:

The GRP communicates with line cards either through the router's switch fabric or its maintenance bus (MBus) facility (see the section entitled "Cisco 12008 Environmental Monitoring Facility" on page 64). The switch fabric provides the data paths for routing table distribution, as well as the means for conveying packets between line cards and the GRP.

The MBus facility enables the GRP to download a system bootstrap image, collect or load diagnostic information, and perform general system maintenance operations.

The GRP contains the following components:

Note EIA/TIA-232 was previously known as recommended standard RS-232 before its acceptance as a standard by the Electronic Industries Association (EIA) and the Telecommunications Industry Association (TIA).

The Cisco 12008 supports downloadable system software for most Cisco IOS software upgrades, enabling you to remotely download, store, and boot from a new Cisco IOS software image.

Summary of GRP Memory Components

Table 1-2 summarizes the memory components of the GRP.


Table  1-2: GRP Memory Components
Memory Type Memory Size Quantity Description
DRAM 641 to 256 MB 1 or 2 64- or 128-MB DIMMs (based on DRAM required) for main Cisco IOS software functions
SRAM 512 KB (fixed)2 SRAM for secondary CPU cache memory functions
NVRAM 512 KB (fixed)3 MVRAM for the system configuration file
Flash memory SIMM4 8 MB 1 Contains Cisco IOS software images and other user-defined files on the GRP
Flash memory (card) 20 MB5 1 or 2 Contains Cisco IOS software images and other user-defined files on up to two PCMCIA-based Flash memory cards6
Flash boot ROM 512 KB 1 Flash EPROM for the ROM monitor program boot image

1 64 MB of DRAM is the default DRAM configuration for the GRP.
2 SRAM is not user configurable or field upgradeable.
3 NVRAM is not user configurable or field upgradeable.
4 The SIMM socket is wired according to Cisco's own design and does not accept industry-standard 80-pin Flash SIMMs.
5 20-MB Flash memory card is the default shipping configuration for the Cisco 12008.
6 A Type 1 or Type 2 PCMCIA card can be used in either PCMCIA slot.
DRAM

The EDO DRAM) on the GRP stores routing tables, networking protocols, and network accounting applications. It also executes the Cisco IOS software.

The standard (default) DRAM configuration for the GRP is 64 MB of EDO DRAM, which you can increase up to 256 MB through available DRAM upgrades.

Two DRAM DIMM sockets are incorporated into the GRP, as shown in Figure 1-10. These sockets, labeled U39 (P4 DRAM bank 1) and U42 (P4 DRAM bank 2), enable you to configure DRAM in increments ranging from 64 MB to 256 MB.

Figure 1-10 shows the location of the two DRAM SIMMs and the Flash SIMM on the GRP.


Figure 1-10: Locations of GRP Memory



Table 1-3 lists the available upgrade configurations for DRAM on the GRP.

Caution To prevent memory problems, DRAM DIMMs must be 3.3 V, 60-nanosecond (ns) devices. Do not attempt to install memory devices in the DIMM sockets that do not meet these requirements.

Table  1-3: DRAM Configurations
Total DRAM Product Numbers DRAM Sockets Number of DIMMs
64 MB1 MEM-GRP/LC-64(=) U39 (bank 1) 1 64-MB DIMM
128 MB MEM-GRP/LC-64(=) U39 (bank 1) and U42 (bank 2) 2 64-MB DIMMs
128 MB MEM-GRP/LC-128(=) U39 (bank 1) 1 128-MB DIMM
256 MB MEM-GRP/LC-256(=) U39 (bank 1) and U42 (bank 2) 2 128-MB DIMMs

1 64 MB is the standard (default) DRAM configuration for the GRP.
SRAM

SRAM provides secondary CPU cache memory. The standard GRP configuration is 512 KB. SRAM functions as a staging area for conveying routing table update information to line cards.

NVRAM

The system configuration files, software configuration register settings, and environmental monitoring logs are contained in the 512-KB NVRAM on the GRP. NVRAM is backed up with built-in lithium batteries that have a minimum life of five years, thus ensuring the stability of NVRAM contents.

Caution Before replacing the GRP in your system, back up the running configuration file to a Trivial File Transfer Protocol (TFTP) file server or to an installed Flash memory card so that you can later retrieve the file. If you do not save the configuration file, the entire file will be lost (because it is contained in NVRAM on the removed GRP); you will have to reenter the entire configuration file manually. Backing up the configuration file is not necessary if you are only temporarily removing a GRP from the system; the lithium batteries on the GRP enable the configuration file to be retained in memory until you reinstall the GRP.
Flash Memory

Both the onboard Flash SIMM and the PCMCIA Flash memory cards allow you to remotely load and store multiple Cisco IOS software and microcode images. You can download a new image over the network or from a local server and then add the new image to Flash memory or replace existing files. You can then boot the router either manually or automatically from any of the stored images.

Flash memory can function much like a TFTP server, allowing other servers to boot remotely from stored images or allowing the servers to copy the images into their own Flash memory.

System Status LEDs

This section describes the two types of system status LEDs used on the GRP: the LED indicators and the alphanumeric LED displays.

These alphanumeric displays provide the following information:

  • System status messages displayed during the boot process. During the boot process, the alphanumeric LED displays are controlled directly by the MBus module.

  • System status messages displayed after the boot process is completed. After the boot process, the alphanumeric displays are controlled by Cisco IOS software (via the MBus); they display messages designated by the software.

The alphanumeric displays provide the following types of information:

  • GRP status

  • System error messages

  • User-defined status and error messages
Soft Reset Switch

A soft reset switch is provided on the GRP faceplate to enable you to reset the software running on the R5000 RISC processor of the GRP. You access this switch through a small aperture in the GRP faceplate. To activate the switch, you can press a ball-point pen or similar pointed instrument into the aperture.

Caution To prevent system problems or loss of data, use the soft reset switch only at the advice of Cisco service personnel.
PCMCIA Slots

The GRP incorporates two PCMCIA slots. Either slot can support a Flash memory card or a similar I/O device, provided that the device requires only +5 VDC. The GRP supports Type 1 and Type 2 devices; it does not support +3.3 VDC PCMCIA devices.

Each PCMCIA slot has an ejector button for ejecting a Flash memory card from the slot.
Asynchronous Serial Ports

Two asynchronous serial ports are provided on the GRP faceplate--a console port and an auxiliary port. These ports enable you to connect external devices that you can use to monitor and manage the system.

Ethernet Port

The GRP incorporates an Ethernet port that you can access using either of the following connection types:

Note The RJ-45 and MII receptacles on the GRP faceplate represent two physical connection options for one Ethernet interface; therefore, you can use either the MDI RJ-45 connection or the MII connection, but not both simultaneously.

Switch Fabric of the Cisco 12008

The heart of the Cisco 12008 is the switch fabric circuitry, which provides synchronized gigabit speed interconnections between the line cards and the GRP. The switch fabric circuitry for the router is incorporated into two cards:

To achieve a fully redundant switch fabric with a switching capacity of 40 Gbps, you can install two CSCs and three SFCs in the router; the second CSC provides redundancy of CSC functions, as well as redundant switch fabric in the event of CSC or SFC failure.

Each CSC or SFC supports an OC-12 switching rate for the router (622 Mbps). By adding the set of three optional SFC cards, you can increase the switching capacity of the router to an OC-48 rate (2.4 Gbps).

Table 1-4 lists the switch fabric bandwidth and the switch card configurations needed to support an OC-12 switching rate or an OC-48 switching rate.


Table  1-4: Switch Fabric Configurations
Switch Fabric Bandwidth Number of CSCs Number of SFCs Planes of Switch Fabric
OC-12 nonredundant 11 0 1
OC-12 redundant 2 0 2
OC-48 nonredundant 1 3 4
OC-48 redundant 2 3 5

1 A CSC is a required router component.

A minimally configured router (one with a single CSC and no SFCs) supports an OC-12 data rate, but provides no redundancy of CSC functions. Adding a second CSC to a system, as well as the three optional SFCs, has the following effects:

Clock and Scheduler Card

The CSC is a multi-function circuit board that can be installed in one or both of two reserved slots (CSC0 and CSC1) in the middle of the upper card cage (see Figure 1-2). The standard router configuration requires one CSC in either slot CSC0 or slot CSC1. If you configure your router with a single CSC, it is recommended that you install it in CSC1.

Each CSC is mounted on its own card carrier and incorporates an onboard power supply that takes the -48 VDC supplied by the backplane and converts it into the 3.3 VDC operating voltage required by the card's electronics.

As a multi-function board, the CSC provides the following system services:

These functions are described in the following sections.

Switch Fabric in the Cisco 12008

A switch plane in the router consists of one OC-12-rate crossbar in the backplane that enables each line card slot in the router to be connected logically to every other line card slot. Line cards installed in any combination of slots in the upper card cage can communicate with each other by means of the router's switch fabric.

The switch fabric of the router constitutes the totality of the possible data paths that can be established through the router. The magnitude of the router's switch fabric (and, hence, its data- carrying capacity) is related directly to the number of switch planes that are made available to the router for data-handling purposes. By installing a second CSC and/or the optional set of three SFCs in the router, you can increase the number of switch planes present in the router, thereby increasing the magnitude of the router's overall switch fabric.

Table 1-5 outlines the possible configurations of CSCs and SFCs and the router switching capacity that results from these configurations.


Table  1-5: Switch Planes Provided by Switch Cards
Switch Card Type Availability Number of Switch Planes Description
One CSC Standard 1 A single CSC supports an OC-12 data rate for the router, but provides no redundancy in the router's switch fabric.
Second CSC Optional 1 A second CSC supports an OC-12 data rate for the router and also provides a redundant plane of switch fabric. If one of the CSCs fails, a fault recovery cutover to the surviving CSC occurs, not only to maintain the router's OC-12 data rate, but also to preserve the system services peculiar to the CSC.
Three SFCs Optional 3 The optional set of three SFCs enables the router to support an OC-48 data rate. In an OC-48 rate1 system, no redundancy exists in the switch fabric. However, if a switch plane failure occurs in a fully-redundant2 system, a CSC can take over the functions of either a failed CSC or a failed SFC, not only to maintain the router's OC-48 data rate, but also to preserve the essential CSC system services.

1 Router equipped with one CSC and three SFCs.
2 Router equipped with two CSCs and three SFCs.
Switch Fabric Controller Functions of the CSC

In addition to providing one plane of switch fabric for the router, the CSC provides numerous other functions and services essential to router operations. Figure 1-11 illustrates the primary functional elements of the CSC.


Figure 1-11: Block Diagram of the CSC



The major functions of each element of the CSC are summarized briefly in the following paragraphs.

In a redundant CSC configuration, the phase of the master clock generator on one card is synchronized with that of the other card. If either clock drifts, the master clock generators on both cards remain tightly aligned.
Should one of the CSCs fail, the phase lock between the two master clock sources is aborted within nanoseconds, enabling the surviving CSC clock to remain stable and take over master clock duties.
In a redundant CSC configuration, either CSC can adopt the frame synchronization phase of the other to ensure phase alignment. The line cards can switch between frame synchronization masters without disruption.
If the frame synchronization function on one CSC fails, cutover to the surviving frame synchronization generator on the other card occurs within nanoseconds, sustaining system operations.
Switch arbitration begins with a set of requests from line cards to send data through the router's switch fabric. The scheduler plans a set of paths through the switch fabric to carry as much data as possible per unit of time. At the next available time unit, the request to send data is granted, and the data is sent to its destination. The next round of switch arbitration (scheduling) then begins.
The scheduler also sends switch fabric control information to each switch plane to create appropriate data paths through the switch fabric. When the new data paths are configured into the switch fabric, data begins to flow toward the destination line card(s).
The central switch allocator and scheduler accepts data transport requests from all line cards (including the GRP), generates grants (accepted data transport requests), and drives all planes of the router's switch fabric.
This single switch plane of the CSC can be used alone in a minimum router configuration, or it can be used in combination with another CSC and the three optional SFCs for full switching redundancy. In the latter case, the per line-card slot bandwidth of the router is increased from an OC-12 rate to an OC-48 rate, and the second CSC provides redundancy.
If any one switch plane fails in a fully redundant switch fabric, the failed plane is shut down, and the router's full data bandwidth is carried by the surviving planes. The fault recovery cutover to another viable switch plane typically occurs without loss of data, because the data path defect is detected while redundancy information is still available, thus enabling error packets to be repaired "on the fly."
Housekeeping and Alarm Monitoring Functions of the CSC

The section describes the following housekeeping and alarm monitoring facilities built into the CSC:

The MBus module on the CSC operates partly autonomously and partly under the control of the master MBus module on the GRP.
A failed MBus module on the CSC is detected by an MBus polling algorithm running in the background on the GRP.
A failed MBus module detected by this polling algorithm in a redundant CSC configuration causes the master MBus module to execute an administrative cutover to the MBus module on the surviving CSC. This cutover is accomplished with no disruption of normal system operations.

Figure 1-12: CSC Alarm Monitoring Facilities


Figure 1-13: Status LEDs on an SFC



Board Power and Fan Tray Power Functions of the CSC

DC-DC converters on the CSC provide power for its own circuitry, as well as power for the fan trays. These functions are described briefly in the following sections.

No redundancy is built into the CSC for the +3.3 VDC operating voltage; if the DC-DC converter fails to deliver this voltage, the card shuts down, at which time the redundant CSC, if installed, takes over to maintain normal system operations.
However, in a nonredundant CSC configuration, the failure of the installed CSC causes the entire system to shut down.
Control of fan power is initiated at system startup, with the fans running at a slow rate for normal operations. Such operation minimizes fan noise, wear, and power consumption. A DC-DC converter on the CSC provides +20 VDC for slow fan operation and +25 VDC for fast fan operation when an overtemperature condition is sensed in the router.
Periodically, the master MBus module on the GRP polls the MBus module on each circuit board to determine whether router components are cool enough to warrant keeping the fans running at their minimum rate. If they are not, the master MBus module directs the MBus module on the CSC to increase the operating voltage being delivered to the fan trays, causing the fans to run faster, thus increasing the volume of air being circulated through the router.
Each fan is monitored separately for failure. A failed fan is not "shut off" in the usual sense; rather, a current-limiting feature in the faulty fan prevents it from interfering with the operation of other fans.
On failure of a fan in either the card cage fan tray or the power supply fan tray, the CSC increases the voltage being delivered to the surviving fans, causing them to run faster to compensate for the failed fan.

Cisco 12000 Series Line Cards

The Cisco 12008 comes equipped with the number and type of line cards that you ordered already installed. Up to seven Cisco 12000 series line cards can be installed in the router to support a variety of physical network media.

The line cards can be installed in upper card cage slots 0 through 3 and slots 4 through 7. Note, however, that it is recommended that the GRP be installed in slot 0. Line cards interface to each other and the GRP through the router's switch fabric.

The following types of line cards are available for use with the Cisco 12008:

These cards provide the interfaces to the router's external physical media. They exchange packet data with each other by way of the router's switch fabric.

Caution Any unoccupied slot in the upper card cage must have a blank filler panel installed for EMI compliance and to ensure proper air flow through the router enclosure.

A vertical cable-management bracket attached to the faceplate of each line card enables you to neatly arrange the network interface cables for connection to the individual ports on the line card. The cable-management system is described in detail in the section entitled "Cable-Management System" on page 8.

The online insertion and removal (OIR) capability of the Cisco 12008 enables you to remove and replace a line card while the system remains powered up and operational.

The Cisco 12000 series line cards available for use with the Cisco 12008 router are described briefly in the following sections.

Quad OC-3c/STM-1c POS Line Card

The Quad OC-3c/STM-1c POS line card provides the Cisco 12008 router with four independent Packet-Over-SONET (POS) ports on a single card. The card interfaces with the router's switch fabric and provides four OC-3c/STM-1c SC-duplex SONET connections. These connections are concatenated, which provides for increased efficiency by eliminating the need to partition the bandwidth.

Figure 1-14 shows a high-level block diagram of the Quad OC-3c/STM-1c POS line card; Figure 1-15 shows a front view of the card.


Figure 1-14: Block Diagram of the Quad OC-3c/STM-1c POS Line Card




Figure 1-15: Quad OC-3c/STM-1c POS Line Card



Each Quad OC-3c/STM-1c POS line card incorporates the following major components:

The SONET specification for fiber-optic transmission defines two types of fiber: single mode and multimode. Signals can travel farther through single mode fiber than through multimode fiber.
The maximum distance for single-mode installations is determined by the amount of light loss in the fiber path. Good quality single-mode fiber with very few splices can carry an OC-3c/STM-1c signal 9.3 miles (15 km) or more; good quality miltimode fiber can carry a signal up to 1.3 miles (2 km).
Burst buffers are used to achieve high throughput while smoothing out the arriving packet burst for the Layer 3 switch processor.
The buffer memory can be configured to support up to 64 MB of receive buffers and up to 64-MB of transmit buffers. The buffers can support delays comparable to the longest round trip delays measured in the Internet at OC-3c/STM-1c line rates.
Once the forwarding decision has been made, the silicon queuing engine is notified by the forwarding processor, and the silicon queuing engine places the packet in the proper queue.
This partitioning between the Layer 2 switching accelerator and the forwarding processor blends the high throughput of hardware-accelerated forwarding with the flexibility of software-based routing.
When an incoming IP packet is clocked into the silicon queuing engine, the packet's integrity is verified by a check of the CRC. Next, the silicon queuing engine transfers the IP packet to buffer memory and tells the Layer 3 switching accelerator the location of the IP packet.
Simultaneously, the silicon queuing engine is receiving forwarding information from the forwarding processor. The forwarding processor tells the silicon queuing engine the virtual output queue where the IP packet is to be placed.
Each virtual output queue represents an output destination (destination line card). This placement of the IP packets in a virtual output queue is based on the decision made by the forwarding processor. There is one virtual output queue for each line card, plus a dedicated virtual output queue for multicast service.
The transmit silicon queuing engine moves the packet from the switch fabric to the transmit buffer, and then to the transmit interface.
Large networks may require more DRAM to support large CEF tables. For information on adding memory to a line card, see the document entitled Cisco 12000 Series Gigabit Switch Router Memory Replacement Instructions.
OC-12c/STM-4c POS Line Card

The OC-12c/STM-4c POS line card provides the Cisco 12008 with a single 622-Mbps Packet-Over-SONET (POS) interface. The card provides one OC-12c/STM-4cc SC duplex single-mode or multimode SONET/SDH connection. This connection is concatenated, which provides for increased efficiency by eliminating the need to partition the bandwidth.

Figure 1-16 shows a high-level block diagram of the OC-12c/STM-4c POS line card; Figure 1-17 shows a front view of the card.


Figure 1-16: Block Diagram of the OC-12c/STM-4c POS Line Card




Figure 1-17: OC-12c/STM-4c POS Line Card



Each OC-12c/STM-4c POS line card incorporates the following primary components:

Each Quad OC-3c/STM-1c POS line card incorporates the following major components:

The SONET specification for fiber-optic transmission defines two types of fiber: single mode and multimode. Signals can travel farther through single mode fiber than through multimode fiber.
The maximum distance for single-mode installations is determined by the amount of light loss in the fiber path. Good quality single-mode fiber with very few splices can carry an OC-3c/STM-1c signal 9.3 miles (15 km) or more; good quality miltimode fiber can carry a signal up to 1640 feet (500 m).
The buffer memory can be configured to support up to 64 MB of receive buffers and up to 64 MB of transmit buffers. The buffers can support delays comparable to the longest round trip delays measured in the Internet at OC-12c/STM-4c line rates
Once the forwarding processor makes a forwarding decision, it notifies the silicon queuing engine, and the silicon queuing engine places the packet in the proper queue.
This partitioning between the Layer 2 switching accelerator and the forwarding processor blends the high throughput of hardware-accelerated forwarding with the flexibility of software-based routing.
When an incoming IP packet is clocked into the silicon queuing engine, packet integrity is verified by a CRC check. Next, the silicon queuing engine transfers the IP packet to buffer memory and tells the Layer 3 switching accelerator the location of the IP packet. Simultaneously, the silicon queuing engine is receiving forwarding information from the forwarding processor. The forwarding processor tells the silicon queuing engine the virtual output queue where the IP packet is to be placed.
Each virtual output queue represents an output destination (destination line card). This placement of the IP packets in a virtual output queue is based on the decision made by the forwarding processor. There is one virtual output queue for each line card, plus a dedicated virtual output queue for multicast service.
The transmit silicon queuing engine moves the packet from the switch fabric to the transmit buffer, and then to the transmit interface.
In addition, the MBus module on the line card contains the ID-EEPROM, which stores the serial number, hardware revision level, and other information about the card.
Large networks may require more DRAM to support large CEF tables. For information on adding memory to a line card, see the document entitled Cisco 12000 Series Gigabit Switch Router Memory Replacement Instructions.
OC-12c/STM-4c ATM Line Card

The OC-12c/STM-4c ATM line card provides the Cisco 12008 with a 622-Mbps ATM interface. The card interfaces to the router's switch fabric, supports from 10 to 40 Gbps, and provides one OC-12c/STM-4c SC duplex single-mode or multimode SONET/SDH connection. This connection is concatenated, which provides for increased efficiency by eliminating the need to partition the bandwidth.

Figure 1-18 shows a high-level block diagram of the OC-12c/STM-4c ATM line card; Figure 1-19 shows a front view of the card.


Figure 1-18: Block Diagram of the OC-12c/STM-4c ATM Line Card




Figure 1-19: Front View of OC-12c/STM-4c ATM Line Card



Each OC-12c/STM-4c ATM line card incorporates the following primary components:

The SONET specification for fiber-optic transmission defines two types of fiber: single mode and multimode. Signals can travel farther through single mode fiber than through multimode fiber.
The maximum distance for single-mode installations is determined by the amount of light loss in the fiber path. Good quality single-mode fiber with very few splices can carry an OC-3c/STM-1c signal 9.3 miles (15 km) or more; good quality miltimode fiber can carry a signal up to 1640 feet (500 m).
Once the forwarding decision has been made, the silicon queuing engine is notified by the forwarding processor, and the silicon queuing engine places the packet in the proper queue.
This partitioning between the Layer 2 switching accelerator and the forwarding processor blends the high throughput of hardware-accelerated forwarding with the flexibility of software-based routing.
When an incoming IP packet is clocked into the silicon queuing engine, the packet's integrity is verified by a CRC check. Next, the silicon queuing engine transfers the IP packet to buffer memory and tells the Layer 3 switching accelerator the location of the IP packet. Simultaneously, the silicon queuing engine is receiving forwarding information from the forwarding processor, while the forwarding processor is telling the silicon queuing engine where the IP packet is to be placed in the virtual output queue.
Each virtual output queue represents an output destination (destination line card). Placement of the IP packets in a virtual output queue is based on the decision made by the forwarding processor. There is one virtual output queue for each line card, plus a dedicated virtual output queue for multicast service.
The transmit silicon queuing engine moves the packet from the switch fabric to the transmit buffer, and then to the transmit interface.
In addition, the MBus module on the line card contains the ID-EEPROM, which stores the serial number, hardware revision level, and other information about the card.
Large networks may require more DRAM to support large CEF tables. For information on adding memory to a line card, see the document entitled Cisco 12000 Series Gigabit Switch Router Memory Replacement Instructions.

Air Filter Assembly

The Cisco 12008 is equipped with a removable air filter that is mounted directly to the router enclosure in front of the lower card cage (see Figure 1-20).

Although the Cisco 12008 will run without an air filter, the air filter should always be present and maintained properly, especially in dirty or dusty environments.

The air filter assembly serves the following purposes:

A metal honeycomb structure built into the air filter assembly provides EMI containment.

You are advised to inspect and clean the air filter at least once a month (or more often in a dusty environment).

Procedures for vacuuming and replacing the air filter are contained in the section entitled "Cleaning the Air Filter" in Chapter 7.

Lower Card Cage and Associated Components

The lower card cage, located directly behind the air filter assembly (see Figure 1-20), houses the card cage fan tray and an optional set of three switch fabric cards (SFCs).

The dimensional characteristics of the SFCs differ markedly from those of the circuit boards in the upper card cage. Three dedicated slots, numbered SFC0, SFC1, and SFC2 as you face the lower card cage, are provided to house the SFCs.

Switch Fabric Cards

The SFCs increase the switching capacity of the Cisco 12008. By adding three SFCs to a router equipped with a single CSC, you increase the bandwidth of each line card slot in the router from an OC-12 rate to an OC-48 rate.

By adding three SFCs to a router equipped with two CSCs, you not only increase the bandwidth of each line card slot to an OC-48 rate, but you also provide a fifth (redundant) switch plane so that the router's OC-48 data rate can be maintained even if a switch plane should fail.

In a router with full switch plane redundancy (that is, a router with five available switch planes), five parallel 1.25 Gbaud serial data streams can be transmitted across the backplane to and from the router's line cards. However, only four of the data streams are required for data transmission purposes; the fifth data stream carries error correction information. If an error occurs on one of the parallel data streams, data in error can be recovered through use of the four remaining correct data streams.

You need not install the optional SFCs in a router that uses line cards having an aggregate bandwidth rate of OC-12 or less. In such a system, a single CSC can provide sufficient bandwidth to accomplish all the router's switching and routing functions. Thus, a minimally configured router does not require the optional switching capacity provided by the SFCs. To increase the switching capacity of the Cisco 12008 to the full OC-48 rate, however, you must install the three optional SFCs.

Each SFC is mounted on its own card carrier and incorporates an onboard power supply that takes the -48 VDC supplied by the backplane and converts it into the 3.3 VDC operating voltage required by the card.


Figure 1-20: Components in the Lower Card Cage



The switching fabric of the SFC is identical to that of the CSC. However, the SFCs do not perform any of the system services native to the CSC (see the section entitled "Clock and Scheduler Card" on page 34). The SFC merely augments the switching capacity of the router.

Power Distribution System in the Cisco 12008

In the Cisco 12008, source AC or source DC power is converted by the installed power supply(ies) into the +5 VDC and -48 VDC required for router operation. These voltages are delivered to the backplane through the blind mating Elcon connector at the rear of the power supply enclosure. The backplane then distributes these operating voltages to all of the installed components in the system (see Figure 1-21).

The +5 VDC is fed to the MBus module on each installed card, and the -48 VDC is fed to a DC-DC converter on each card.

The DC-DC converter on each card operates under control of the card's MBus module. When directed by the GRP or system software during normal system startup, the DC-DC converter on each card is activated to convert the -48 VDC from the backplane into the voltages required to power the card's electronic circuitry.

The card cage fan tray and the power supply fan tray derive their operating power from a DC-DC converter on the CSC. This converter takes the -48 VDC from the backplane and converts it into the +24 VDC operating voltage required by the fan trays.

If an overtemperature condition is sensed anywhere within the router, or if any one of the fans fails in either the card cage fan tray or the power supply fan tray, the DC-DC converter on the CSC increases the voltage being delivered to the fan trays. This causes the fans to run at maximum speed to increase the volume of cooling air flowing through the router. Once the overtemperature condition is resolved, the fans revert to their normal operating speed.

Because the fans must operate continuously to prevent thermal damage to router components, they cannot be turned off by software.


Figure 1-21: Power Distribution System in the Cisco 12008

Cisco 12008 Environmental Monitoring Facility

An environmental monitoring facility, called the maintenance bus (MBus), supports a variety of functions essential to router operations. These functions include the following:

The MBus facility in the router is interconnected by means of the backplane to the following components:

Each of the components listed here contains an onboard MBus module that incorporates two separate transceivers (A and B). Each transceiver has a separate etch (communication path) through the backplane. Consequently, all the MBus modules in the system are reliably interconnected to each other by means of redundant busses. This redundancy enhances the reliablity of the entire environmental monitoring system.

The MBus module on each component is powered by +5.2 VDC that it receives through the backplane from the power supply. A single MBus firmware image executes on all the MBus modules present in the system.

The master MBus module on the GRP monitors all the alarm conditions detected by the MBus modules in the other components of the system. The master MBus module then determines an appropriate response to the alarm condition.

The MBus modules on installed components perform the following functions:

The MBus modules on other installed components then power up on command from the master MBus agent on the GRP.
A message is sent from the master GRP MBus agent, requesting that all installed components identify themselves. Each return response includes slot number, card type, and component type.
Because the MBus is slow relative to the switch fabric, only enough code is initially downloaded to the line card to enable it to access the router's switch fabric.
This initial code includes a line card fabric downloader that functions as a secondary bootstrap program to quickly complete the downloading of the Cisco IOS image to the line card by means of the router's high-speed switch fabric.

System Specifications

Table 1-6 lists the physical specifications of the Cisco 12008.

Table 1-7 outlines the electrical specifications of the AC-input power supply; Table 1-8 outlines similar specifications for the DC-input power supply.

Table 1-9 lists the environmental specifications of the Cisco 12008.


Table  1-6: Physical Specifications of the Cisco 12008
Description Value
Chassis height 24.8 inches (63.6 cm)
Chassis width 17.4 inches (44.6 cm)

19.1 inches (48.5 cm), including mounting flanges

Chassis depth 21.2 inches (54.4 cm), including cable- management system
Weight, maximum configuration 180 lb (81.7 kg) with two DC-input power supplies

187 lb (84.9 kg) with two AC-input power supplies

Weight, minimum configuration 127 lb (57.7 kg)
Weight, shipping pallet 44 lb (20 kg)
Weight, total system, on pallet 231 lb (104.9 kg)
Weight, base chassis with backplane 50 lb (22.7 kg)
Weight, card cage fan tray 12 lb (5.4 kg)
Weight, power supply fan tray 2 lb (0.9 kg)
Weight, AC-input power supply 17 lb (7.7 kg)
Weight, DC-input power supply 14 lb (6.4 kg)
Weight, line card 8 lb (3.6 kg)
Weight, GRP 8 lb (3.6 kg)
Weight, CSC 7 lb (3.2 kg)
Weight, SFC 2 lb (0.9 kg)

Table  1-7: Electrical Specifications of the AC-Input Power Supply
Power Supply Type Electrical Characteristic Value
AC Input power Maximum: 2000W
200 VAC to 240 VAC @ 10A
AC Input voltage Nominal: 200 VAC to 240 VAC
Acceptable range: 180 VAC to 264 VAC, single phase
AC Input current 9.5A @ 200 VAC
AC Line frequency 47 to 63 Hz
AC Output power Maximum: 1560W
-48 VDC @ 33.7A
+5 VDC @ 20.8A)

Table  1-8: Electrical Specifications of the DC-Input Power Supply
Power Supply Type Electrical Characteristic Value
DC Input power Maximum: 1580W
-40.5 VDC to -75 VDC @ 39A to 21A
DC Input voltage Nominal: -48 VDC (United States)
Acceptable range: -40.5 VDC to -56 VDC
Nominal: -60 VDC (International)
Acceptable range: -58 VDC to -75 VDC
DC Input current 33.75A maximum @ -48 VDC
27A maximum @ -60 VDC
Internal circuit breaker is rated at 40A
DC Output power Maximum: 1542W
-48 VDC @ 33.7A
+5 VDC @ 20.8A

Table  1-9: Environmental Specifications of the Cisco 12008
Description Value
Temperature Operating: 32° to 104° F (0° to 40° C)
Nonoperating: -4° to 149° F (-20° C to 65° C)
Humidity Noncondensing, operating: 10 to 90%
Noncondensing, nonoperating: 5 to 95%
Altitude Operating: 0 to 10,000 ft (0 to 3048 m)
Nonoperating: 0 to 30,000 ft (0 to 9144 m)
Heat dissipation 6,000 Btu/hr maximum
Acoustic Noise 69 dbA maximum
Shock Operating: 5 to 500 Hz, 0.5 g1 (0.1 oct/min2)
Nonoperating: 5 to 100 Hz, 1 g (0.1 oct/min);
100 to 500 Hz, 1.5g (0.2 oct/min);
500 to 1000 Hz, 1.5 g (0.2 oct/min)

1 g = gravity.
2 oct/min = octave per minute.

Agency Approvals

In addition to meeting GR-63-CORE and GR-1089-CORE specifications, the Cisco 12008 meets the requirements of the agencies listed in Table 1-10.


Table  1-10: Agency Approvals
Category Agency Approval
Safety UL 1950
CSA 22.2 No. 950
EN60950
AUSTEL TS001
AS/NZS 3260
EMI FCC Class A
CSA Class A
EN55022 Class A
VCCI Class 2
AS/NRZ 3548 Class A
Immunity EN61000-4-2/IEC-1000-4-2
EN61000-4-3/IEC-1000-4-3
EN61000-4-4/IEC-1000-4-4
EN61000-4-5/IEC-1000-4-5
EN61000-4-6/IEC-1000-4-6
EN61000-4-11/IEC-1000-4-11

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