Installing the Software

Each router comes with JUNOS software installed on it. When the router is powered on, all software starts automatically. The software is then configured, and the router is ready to participate in the network.

The software is installed on the router's flash drive and hard drive. A copy of the software also is provided on a removable PC card (or, on some M40 routers, an LS-120 floppy disk), which can be inserted into the router's card slot (for the LS-120, the floppy drive). Normally, when the router is powered on, it runs the copy of the software that is installed on the flash drive.

The router software can be upgraded as new features are added or software problems are fixed. Software can be upgraded by downloading images onto the router or onto another system on the network, then installing them on the router's flash and hard drives . The software can also be copied onto the removable media. If the software on the flash, hard disk, or removable media becomes damaged, the software can be reinstalled onto those devices.

The JUNOS software comprises collections of files called packages. Each JUNOS software release consists of the following packages: the base package (jbase), which contains additions to the operating system; the kernel and network tools package (jkernel), which contains the operating system; the routing package (jroute), which contains the software that runs on the Routing Engine; the Packet Forwarding Engine package (jpfe); the crypto package (jcrypto), which contains security software (in the domestic version only); and the documentation package (jdocs), which contains the documentation for the software.

These software packages are provided as a single unit, called a bundle (jbundle). The bundle can be used to upgrade all the packages at once, or packages can be upgraded individually. When upgrading to a new major release, the bundle must be used to upgrade all the software to the new level.

Two sets of JUNOS software packages are provided, one for customers in the United States and Canada and another for customers in other parts of the world. The worldwide version does not include any capabilities that provide encryption of data leaving the router. Otherwise, the two packages are identical.

A JUNOS software release has a name in the following format: junos- m.nZnumber.m.n is two integers that represent the software release number; m denotes the major release number. Z is a capital letter that indicates the type of software release. In most cases, it is an R , to indicate that this is released software. The letters A (for alpha-level software), B (for beta-level software), or I (a capital letter I; for internal, test) are used for prerelease versions of the software. number represents the version of the major software release. An example of a software release name is: junos-5.3R1.

A software package has a name in the following format: package- name-release .tgz. package-nam e is the name of the package. release is the software release number; for example, 5.4R1 or 5.2R2.3. Examples of package names are jroute-5.4R1.tgz , jkernel-5.4R1.tgz , jpfe-5.4R1.tgz , and jinstall-5.4R1.tgz .

Table 4.9 lists the storage media (flash drives, hard drives, and removable media) device names which are displayed when the router boots.

The router typically boots from the flash disk. (It is also possible to boot the router from the hard drive or the removable media.) These disks are referred to as the boot devices. The disk from which the router boots is called the primary boot device, and the other disk is the alternate boot device. The primary boot device is generally the flash disk, and the alternate boot device is generally the hard disk.

Table 4.9. Release 5.x Device Names

Device	CPV5000	Teknor
Flash drive	ad0	ad0
Hard drive	ad2	ad1
Removable media	afd0	ad4

Normally, the router boots from the flash disk. If it fails, it attempts to boot from the hard drive, which is the alternate boot device.

If a PC card (or floppy disk) is installed when the router boots, the router attempts to boot from the image on the card or disk. If the router fails, it next tries the flash disk and finally the hard disk.

If the router boots from an alternative medium, the JUNOS software displays a message indicating this when logging in to the router. For example, the following message shows that the software booted from the hard disk (/ dev/ad2 ):

 login:  username  Password:  password  Last login:  date  on  terminal  --- JUNOS 5.3R1 built  date  --- --- NOTICE: System is running on alternate media device ( /dev/ad2).