Hardware Overview (J Series Routers)
The Junos OS is installed on the internal CompactFlash card. This internal CompactFlash card is the primary and only boot drive on the J Series routers when they are delivered from the factory. All J Series routers have one or more USB ports. The 4300 and 6300 J Series routers also include an external CompactFlash card slot. You can install external storage devices through the USB ports and CompactFlash card slots. When external storage devices are installed, these external devices can be used as backup boot drives. You can also create a backup internal boot drive on any externally attached CompactFlash card. This CompactFlash card can then be used to replace the internal CompactFlash card on the J Series router in the event that the internal card is damaged or otherwise made unusable by the router. Figure 1 shows the location of the memory and ports on a J Series router.
Figure 1: J Series Routers (J4300 Shown)
The J Series routers include the following:
System Memory
Starting with Junos OS Release 9.1, all J Series routers require a minimum of 512 MB of router memory on each Routing Engine. Any router without this minimum requires a system memory upgrade before you install Junos OS Release 9.1. To determine the amount of memory currently installed on your router, use the CLI show chassis routing-engine command.
For more information about memory requirements for the J Series routers, see the Customer Support Center JTAC Technical Bulletin PSN-2008-04-021: http://www.juniper.net/alerts/viewalert.jsp?txtAlertNumber=PSN-2008-04-021&actionBtn=Search.
Storage Media
The J Series routers use the following media storage devices:
- Internal CompactFlash card—The CompactFlash card is the primary boot device.
- External media device—Depending on the system, this external device can be a CompactFlash card or a USB storage device. Juniper Networks recommends that you attach an external device to the system and use this external device as the backup boot device for the system.
