Maintaining the Cisco 2524 and Cisco 2525 Routers

Warning Before working on a chassis or working near power supplies, unplug the power cord on AC units; disconnect the power at the circuit breaker on DC units. (To see translated versions of this warning, refer to the appendix "Translated Safety Warnings.")

Installing WAN Modules

You can install WAN modules in the router without removing the chassis cover. Each router chassis can accommodate up to three WAN modules---two synchronous serial and one ISDN. The choice of synchronous serial WAN modules is as follows:

• 2-wire switched 56-kbps DSU/CSU
  

• 4-wire 56/64-kbps DSU/CSU
  

• Fractional T1/T1 DSU/CSU
  

• Five-in-one synchronous serial
  

The choice of ISDN WAN modules is as follows:

• ISDN BRI
  

• ISDN with integrated NT1 device
  

The ISDN WAN modules are designed so that you cannot insert them into the synchronous serial WAN slots. A blank slot cover is installed over unused slots.

Take the following steps to install a WAN module:

Step 1 Turn OFF power to the router.

Caution Unlike some other Cisco routers, the WAN modules are not hot-swappable (that is, you cannot remove or install them when power to the router is ON). Be sure to turn OFF power to the router before installing or removing WAN modules. Failure to do so may damage or halt the router.

Step 2 Remove the WAN module from the ESD-protective shipping material.

Step 3 Slide the WAN module into the appropriate slot along the card guides until it is completely seated in the connector inside the router (see Figure A-1).

Step 4 Tighten the two captive screws on the module to secure it to the chassis.

Caution Although there are three slots available for the WAN modules, the slot on the far right (labeled BRI 0) is reserved for an ISDN WAN module only. Install all other modules in the slots labeled SERIAL 0 and SERIAL 1. The ISDN WAN modules are designed so that you cannot insert them into the synchronous serial slots.

Figure A-1 : Installing a WAN Module

Step 5 If your router is configured with less than three WAN modules, make sure a blank slot cover is installed over each open slot to ensure proper airflow inside the chassis.

Opening the Chassis

This section describes the procedure for opening the chassis by removing the chassis cover.

Warning Do not touch the power supply when the power cord is connected. For systems with a power switch, line voltages are present within the power supply even when the power switch is OFF and the power cord is connected. For systems without a power switch, line voltages are present within the power supply when the power cord is connected. (To see translated versions of this warning, refer to the appendix "Translated Safety Warnings.")

Tools Required

You will need the following tools to open the chassis:

• Medium-size flat-blade screwdriver (1/4 inch [0.625 cm])
  

• Size M 3.5 (metric) hex-head nut driver (optional)
  

Removing the Chassis Cover

You must open the router chassis to gain access to its interior components: the system card, system-code single in-line memory modules (SIMMs), and DRAM SIMMs. When opening the chassis, refer to Parts A and B in Figure A-2.

Warning Before opening the chassis, disconnect the telephone-network cables to avoid contact with telephone-network voltages. (To see translated versions of this warning, refer to the appendix "Translated Safety Warnings.")

Take the following steps to remove the chassis cover:

Step 1 Turn OFF the power, but to channel electrostatic discharge (ESD) voltages to ground, do not unplug the power cable.

Step 2 Remove all interface cables from the rear panel of the router.

Step 3 Turn the unit upside down so that the top of the chassis is resting on a flat surface, and the front of the chassis is toward you. (See Figure A-2, Part A.)

Figure A-2 : Chassis Cover Removal

Step 4 Remove the single screw located on the bottom of the chassis (on the side closest to you). Note that the chassis is comprised of two sections: top and bottom.

Step 5 If required, insert a medium-size flat-blade screwdriver into the slots shown in Figure A-2, Part A, and gently rotate the blade so that the top and bottom sections separate slightly.

Step 6 Holding the chassis with both hands, position it as shown in Figure A-2, Part B.

Step 7 Pull the top section away from the bottom section. (See Figure A-2, Part B.) The fit is very snug, so it may be necessary to pry the chassis sections apart at one end and then the other until they separate.

Step 8 When the top cover is off, set it aside. Figure A-3 shows the layout of the system card, which is attached to the bottom section of the chassis.

Figure A-3 : System Card Layout---Cisco 2524

Upgrading the Boot Flash Memory

Take the following steps to upgrade the boot Flash memory:

Step 1 Turn OFF power, but to channel ESD voltages to ground, do not unplug the power cord.

Step 2 Attach an ESD-preventive wrist strap.

Step 3 Open the cover following the instructions in the section "Opening the Chassis" earlier in this appendix.

Step 4 Insert the Flash memory card into the Personal Computer Memory Card International Association (PCMCIA) slot.

Step 5 Turn ON power to the router. The system copies the boot image on the Flash memory card to the boot Flash memory on the system card:

Cisco Systems

Diagnostic Monitor

Testing boot state

Exiting boot state

Testing Main Memory from 0h to C000h. data equals address

Testing Main Memory from 0h to C000h. checkerboard

Testing Main Memory from 0h to C000h. inverse checkerboard

Clearing bss

Enabling interrupts

Exiting init

Boot flash size = 0x200000

etext = 0x1006860

addr = 0x1006861

beginning of header file addr = 0x1006874

got the flash file header number 1

Program flash location 0x81ed000

Boot flash frier is successful.

Please turn off the system and remove the Flash Credit Card.

Step 6 Remove the Flash memory card and turn ON power to the router.

Upgrading the DRAM SIMM

This section describes how to upgrade the DRAM SIMM on the system card. You might need to upgrade the DRAM SIMM for the following reasons:

• You upgrade the Cisco IOS feature set or release.
  

• Your router maintains large routing tables or other memory-intensive features, such as spoofing or protocol translations.
  

There are two types of DRAM memory in the Cisco 2524 and Cisco 2525 routers: fixed DRAM soldered on the system card and a removable DRAM SIMM (see Figure A-3). The DRAM SIMMs are available in 4, 8, or 16 MB. Depending on the Cisco IOS feature set originally ordered with your router, it may or may not include fixed DRAM. If the Cisco IOS feature set requires a DRAM configuration other than 4, 8, or 16 MB, your router will have a combination of fixed DRAM and a DRAM SIMM. For example, if the Cisco IOS feature set originally ordered with your router requires 6-MB DRAM, your router will include 2-MB fixed DRAM and a 4-MB DRAM SIMM for a total of 6-MB DRAM (because a 6-MB DRAM SIMM is not available).

The system allocates the total memory installed on the fixed DRAM or the DRAM SIMM as primary and shared memory. Primary memory is used to store the operating configuration, routing tables, caches, queues, and packets. Shared memory is used to store incoming and outgoing packets.

Table A-1 describes the relationship between the physical configuration of DRAM (that is, fixed DRAM and which size DRAM SIMM are needed to obtain from 2- to 18-MB of total DRAM) and how the system allocates the DRAM as shared and primary DRAM.

Table A-1 : DRAM Physical Configuration and System Allocation

	Physical Configuration		System Allocation
Total DRAM (MB)	Fixed DRAM (MB)	DRAM SIMM (MB)	Shared DRAM (MB)	Primary DRAM (MB)
2	2	--	1	1
4	--	4	2	2
6	2	4	2	4
8	--	8	2	6
10	2	8	2	8
16	--	16	2	14
18	2	16	2	16

To see how much memory is currently installed in the router, enter the show version command. Near the middle of the resulting output, a message similar to the following displays:

Cisco XXXX(68030) processor (revision X) with 4092K/2048K bytes of memory.

This line shows how much memory is installed (in this example, 4092K/2048K). The first number represents primary memory and the second number represents shared memory.

Tools and Equipment Required

You will need the following tools to remove and replace the DRAM SIMM on the router:

• Medium-size flat-blade screwdriver (1/4 inch [0.625 cm])
  

• ESD-preventive wrist strap
  

• The DRAM SIMM required for your planned upgrade
  

DRAM SIMM Installation

Take the following steps to install the DRAM SIMMs:

Step 1 Turn OFF power to the router, but to channel ESD voltages to ground, do not unplug the power cord.

Step 2 Attach an ESD-preventive wrist strap.

Step 3 Open the cover following the instructions in the section "Opening the Chassis" earlier in this appendix.

Step 4 Orient the chassis as shown in Figure A-3, with the primary-memory DRAM SIMM socket toward you.

Step 5 Remove the existing DRAM SIMM by pulling outward on the connectors to unlatch them, as shown in Figure A-4. Be careful not to break the holders on the SIMM connector.

Caution To prevent damage, do not press on the center of the SIMMs. Handle each SIMM carefully.

Figure A-4 : Removing and Replacing the DRAM SIMM

Step 6 Using the system card orientation shown in Figure A-4, position the new SIMM so that the polarization notch is located at the right end of the SIMM socket.

Step 7 Insert the new DRAM SIMM by sliding the end with the metal fingers into the SIMM connector socket at approximately a 45-degree angle to the system card. Gently rock the SIMM back into place until the latch on either side snaps into place. Do not use excessive force because the connector may break.

Step 8 Replace the router cover. Follow the instructions in the section "Closing the Chassis" later in this appendix.

Step 9 Connect the router to a console terminal.

Step 10 Turn ON power to the router. If error messages relating to memory are displayed, remove the DRAM SIMM and reinstall it, taking care to firmly seat the SIMM in its socket.

Replacing System-Code SIMMs

The system code (software) is stored in Flash memory SIMMs. The 80-pin Flash memory SIMMs must be purchased from Cisco Systems. Contact a customer service representative for more information.

> b [tftp] flash filename

router> enable
password: enablepassword
router# conf term
Enter configuration commands, one per line.
Edit with DELETE, CTRL/W, and CTRL/U; end with CTRL/Z 
config-register 0x102
boot system flash [filename]
^Z
router# 

router> enable
Password: enablepassword
router# config term
Enter configuration commands, one per line.
Edit with DELETE, CTRL/W, and CTRL/U; end with CTRL/Z
config-reg 0x2102
^Z
router#