M20 SSB Installation Instructions
Part No. 530-001668-01
Revision 2
31 March 2000
This document describes how to install a System and Switch Board (SSB) into an M20
Internet Backbone Router.
For additional installation and configuration information, refer to the following
documentation:
n M20 Internet Backbone Router Hardware Installation Guide
n JUNOS Internet Software Configuration Guide
n JUNOS Internet Software Command Reference
Contents
SSB Description ....................................................................................................................1
Tools and Parts Required .....................................................................................................3
Remove the Existing SSB .....................................................................................................3
Install the Replacement SSB .................................................................................................4
Verify That the SSB Is Installed Correctly ..............................................................................5
Contact Juniper Networks .....................................................................................................6
SSB Description
The SSBs occupy the top slots of the card cage, installing into the midplane from the front of
the chassis (see Figure 1). Each SSB houses an Internet Processor ASIC and two Distributed
Buffer Manager ASICs. The SSB communicates with the Routing Engine using a dedicated
100-Mbps Fast Ethernet link that transfers routing table data from the Routing Engine to the
forwarding table in the Internet Processor ASIC. The link is also used to transfer from the SSB
to the Routing Engine routing link-state updates and other packets destined for the router
that have been received through the router interfaces. Figure 2 shows the SSB.
An M20 router can have up to two SSBs for redundancy. If two SSBs are installed, one acts as
master and the other acts as backup. If the master SSB fails or is removed, the backup
restarts and becomes the master SSB.
The following SSB functions cannot occur while both SSBs are removed from the router:
n Route lookups
n Monitoring of system components
n Transfer of exception and control packets
n FPC resets
M20 SSB Installation Instructions
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1
SSB Description
2
SSBs are hot-insertable and hot-removable. You can remove and replace an SSB without
powering down the router. You can remove both SSBs, but doing so interrupts packet
forwarding and the Routing Engine responds by sending alarms through the Ethernet
channel to the management console. When an SSB is replaced, it is rebooted by flash
EEPROM.
The M20 can also have two Routing Engines for redundancy. When you remove both Routing
Engines, the master SSB enters a warm shutdown mode and continues its forwarding process
for a limited time using a frozen forwarding table. The time limit is determined by a timer in
the SSB. If you replace the Routing Engine during the warm shutdown period, the SSB
unfreezes its forwarding tables and resumes normal functioning. Otherwise, the SSB shuts
itself down.
Figure 1: Front of Chassis
Fan tray
assemblies
SSB0
SSB1
Craft
interface
FPC0
FPC1
FPC2
FPC3
1111
Cable management system
Figure 2: System and Switch Board
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M20 SSB Installation Instructions
Tools and Parts Required
Tools and Parts Required
To replace an SSB, you need the following tools and parts:
n Phillips (+) screwdrivers, numbers 1 and 2
n Electrostatic bags, one for each SSB removed
n ESD grounding wrist strap
Remove the Existing SSB
To remove the SSB, follow this procedure (see Figure 3):
1.
Attach an ESD wrist strap to your bare wrist and connect the wrist strap to one of the
two ESD points on the chassis.
2.
Locate the SSB offline switch on the craft interface (see Figure 1) and press and hold
down the switch for five seconds to take the SSB offline.
If you do not take the SSB offline before removing it, the
router might lose data.
If you have redundant SSBs, when you take the master SSB
offline the backup SSB will take over as master.
3.
Using the screwdriver, unscrew the thumbscrews on the left and right sides of the card
carrier to unseat the SSB from the midplane.
4.
Flip the ends of the two extractor clips, which are adjacent to the thumbscrews, towards
the outside edges of the router.
5.
Grasp both sides of the card carrier and slide the SSB about three-quarters of the way out
of the router.
6.
Place one of your hands underneath the SSB to support it, and slide it completely out of
the chassis.
M20 SSB Installation Instructions
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3
Install the Replacement SSB
Figure 3: Remove the SSB
4
M20 SSB Installation Instructions
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Install the Replacement SSB
To install the replacement SSB, follow this procedure (see Figure 4):
1.
Attach an ESD wrist strap to your bare wrist and connect the wrist strap to one of the
two ESD points on the chassis.
2.
Grasp the front of the SSB card carrier with both hands and align the rear of the card
carrier with the slide guides on the chassis.
3.
Slide the SSB card carrier all the way into the card cage until it contacts the midplane.
4.
Flip the extractor clips, located on the left and right sides of the card carrier, towards
each other to lodge the SSB in place.
5.
Tighten the thumbscrews on the left and right sides of the card carrier to seat the SSB.
To seat the SSB properly, be sure to tighten the screws
adequately. If the SSB is not seated properly, it will not
function.
Verify That the SSB Is Installed Correctly
1126
Figure 4: Reinstall the SSB
Verify That the SSB Is Installed Correctly
When the SSB is installed into a running router, it is booted by flash EEPROM.
To verify that the SSB is functioning normally, check the LEDs on its faceplate (see Figure 5
and Table 1).
To check the status of the SSB, use the following CLI command:
user@host> show chassis ssb
For more information about using the CLI, see the JUNOS Internet software manuals.
Figure 5: SSB LEDs
STATUS
Debug port
SSB status LEDs
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SSB
OFFLINE ONLINE
MASTER
SSB LEDs
SSB offline switch
M20 SSB Installation Instructions
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5
Contact Juniper Networks
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Table 1: SSB LEDs
6
M20 SSB Installation Instructions
Color
Label
State
Description
Amber
OFFLINE
On steadily
SSB is offline.
Green
OFFLINE
On steadily
SSB processor is running.
Blue
MASTER
On steadily
SSB is master.
Green
STATUS (left)
Blinking
SSB processor is running. Normally, the blinking is
faint and becomes bright only when the SSB is
processing many exceptions.
Green
STATUS (right)
Flashing
I/O interrupts are occurring.
Contact Juniper Networks
For technical support, contact Juniper Networks at [email protected]. If you are reporting a
software problem, please issue the following command from the CLI before contacting
support:
user@host> request support information | save filename
For documentation issues, contact Juniper Networks at [email protected].
To provide a core file to Juniper Networks for analysis, gzip the file, rename the file to include
your company name, copy it to ftp.juniper.net:pub/incoming, and then send the filename,
along with software version information (the output of the show version command) and the
configuration, to [email protected].
Juniper Networks is a registered trademark of Juniper Networks, Inc. JUNOS, M20, M40, and M160 are trademarks of Juniper Networks, Inc. All other
trademarks, service marks, registered trademarks, or registered service marks may be the property of their respective owners. All specifications are
subject to change without notice.
Copyright © 1999-2000, Juniper Networks, Inc.
All rights reserved. Printed in USA.
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