• Related Topics
• Router Architecture for M Series Routers and T Series Routers: http://www.juniper.net/techpubs/software/nog/nog-baseline/html/juniper-routers3.html
• Hardware Components of the M Series and T Series Routers: http://www.juniper.net/techpubs/software/nog/nog-baseline/html/juniper-routers7.html

Boot Sequence (M Series, MX Series, T Series, TX Matrix, and TX Matrix Plus Routers)

tThe M Series, MX Series (except for the MX80 routers), T Series, and TX Matrix routers attempt to boot from the storage media in the following order:

1. Removable media
2. CompactFlash card (if available)
3. Hard disk

MX80 routers attempt to boot from the storage media in the following order:

1. USB media
2. Dual, internal NAND flash device (first da0, then da1)

The TX Matrix Plus router attempts to boot from the storage media in the following order:

1. USB media
2. CompactFlash card (if available)
3. Disk 1
4. Storage media available on the LAN

Note: Do not insert the removable media during normal operations. The router does not operate normally when it is booted from the removable media.

If the router boots from an alternate boot device, the Junos OS displays a message indicating this when you log in to the router. For example, the following message shows that the software booted from the hard disk (/dev/ad2s1a):