Configuring Autoinstallation of Configuration Files on ACX Series (Junos OS)

Autoinstallation provides automatic configuration for a new router that you connect to the network and turn on, or for a router configured for autoinstallation. The autoinstallation process begins anytime a router is powered on and cannot locate a valid configuration file in the CompactFlash (CF) card. Typically, a configuration file is unavailable when a router is powered on for the first time, or if the configuration file is deleted from the CF card. The autoinstallation feature enables you to deploy multiple routers from a central location in the network.

For the autoinstallation process to work, you must store one or more host-specific or default configuration files on a configuration server in the network and have a service available—typically Dynamic Host Configuration Protocol (DHCP)—to assign an IP address to the router.

Autoinstallation takes place automatically when you connect an Ethernet on a new Juniper Networks router to the network and power on the router. To simplify the process, you can explicitly enable autoinstallation on a router and specify a configuration server, an autoinstallation interface, and a protocol for IP address acquisition.

• Supported Autoinstallation Interfaces and Protocols
• Typical Autoinstallation Process on a New Router

To configure a router for autoinstallation, complete the following tasks:

• Make sure you have a DHCP server on your network to meet your network requirements.

• Create one of the following configuration files and store it on an HTTP, FTP, or TFTP server in the network:

  • A host-specific file with the name hostname.conf for each router undergoing autoinstallation. Replace hostname with the name of a router. The hostname.conf file typically contains all the configuration information necessary for the router with this hostname.

  • A default configuration file named router.conf with the minimum configuration necessary to enable you to telnet into the new router for further configuration.

• Physically attach the router to the network using a Gigabit Ethernet interface.

• If you configure the DHCP server to provide only the HTTP, FTP, or TFTP server hostname, add an IP address-to-hostname mapping entry for the HTTP, FTP, or TFTP server to the DNS database file on the DNS server in the network.

• If the new router is not on the same network segment as the DHCP server (or other router providing IP address resolution), configure an existing router as an intermediate to receive HTTP, FTP, or TFTP and DNS requests and forward them to the HTTP, FTP, or TFTP and DNS servers. You must configure the LAN on the intermediate router with the IP addresses of the hosts providing HTTP, FTP, or TFTP and DNS service. Connect this interface to the new router.

• If you are using hostname.conf files for autoinstallation of host-specific configuration files, you must also complete the following tasks:

  • Configure the DHCP server to provide a hostname.conf filename to each new router. Each router uses its hostname.conf filename to request a configuration file from the TFTP server. Copy the necessary hostname.conf configuration files to the TFTP server.

  • Create a default configuration file named network.conf and copy it to the TFTP server. This file contains IP address-to-hostname mapping entries. If the DHCP server does not send a hostname.conf filename to a new router, the router uses network.conf to resolve its hostname based on its IP address.

    Alternatively, you can add the IP address-to-hostname mapping entry for the new router to a DNS database file.

    The router uses the hostname to request a hostname.conf file from the server.

• Purpose
• Action
• Meaning

The ACX Series router has an autoinstallation mechanism that allows the router to configure itself out-of-the-box with no manual intervention, using the configuration available either on the network, locally through a removable media, or a combination of both.

Autoinstallation process delivers the following benefits:

• The router can be sent from the warehouse to the deployment site without any pre-configuration steps.

• The procedure required to deploy the device at the cell site is simplified, resulting in reduced operational and administrative costs.

• You can roll out large numbers of these devices in a very short time.

ACX Series routers support the retrieval of partial configuration from an external USB storage device plugged into the router’s USB port during the autoinstallation process. This partial configuration in turn facilitates the network mode of autoinstallation to retrieve the complete configuration file from the network. This method is called hybrid mode of autoinstallation.

Autoinstallation process operates in three modes:

• USB mode—Autoinstallation obtains the required configuration from the configuration file saved in an external USB storage device plugged into the router.

• Network Mode—Autoinstallation triggers IP address acquisition mechanism (the router sends out DHCP or RARP requests on each connected interface simultaneously) to obtain an IP address. Once the router has an IP address, it sends a request to the specified configuration server and downloads and installs the configuration.

• Hybrid mode—Autoinstallation obtains partial configuration from an external USB storage device and uses that configuration to obtain the complete configuration file in network mode. This mode is a combination of USB mode and Network mode.

On the different ACX Series routers, autoinstallation is supported on the following Gigabit Ethernet (ge) and 10- Gigabit Ethernet (xe) interfaces:

• On ACX1000 routers, interfaces ge-0/1/0 through ge-0/1/7, and ge-0/2/0 through ge-0/2/3

• On ACX1100 routers, interfaces ge-0/0/0 through ge-0/0/7, and ge-0/1/0 through ge-0/1/3

• On ACX2000 routers, interfaces ge-0/1/0 through ge-0/1/7, ge-0/2/0 through ge-0/2/1, and xe-0/3/0 through xe-0/3/1

• On ACX2100 routers, interfaces ge-1/0/0 through ge-1/0/3, ge-1/1/0 through ge-1/1/3, ge-1/2/0 through ge-1/2/1, and xe-1/3/0 through xe-1/3/1

• On ACX2200 routers, interfaces ge-0/0/0 through ge-0/0/3, ge-0/1/0 through ge-0/1/3, ge-0/2/0 through ge-0/2/1, and xe-0/3/0 through xe-0/3/1

• On ACX4000 routers, interfaces ge-0/0/0 through ge-0/0/7, ge-0/1/0 through ge-0/1/1, ge-1/0/0 through ge-1/0/5, ge-1/1/0 through ge-1/1/5 , and xe-0/2/0 through xe-0/2/1

Before you perform autoinstallation on a router in hybrid mode, complete the following tasks:

Using a text editor on a PC or laptop, create the configuration file, named juniper-config.txt, as a sequence of configuration commands (“set” commands). To reuse configuration from another ACX Series router, the configuration can be saved in configuration mode as a sequence of configuration commands on the router using the “show | display set | save <filename>” command and then copying the <filename> to the PC or router as juniper-config.txt.

You must copy the juniper-config.txt file to an external USB storage device. Plug the USB device into the USB port on the new ACX Series router. When you power on the router, the router first attempts to access the external USB storage device. The router reads the juniper-config.txt file from the external USB storage device and commits the configuration.

Perform all of the steps described in the Before You Begin Autoinstallation on an ACX Series Universal Metro Router section, which prepares the router for network-based autoinstallation.

You can perform autoinstallation on a new ACX Series router in hybrid mode, which is a combination of the USB-based autoinstallation process and the network-based autoinstallation process.

This configuration method has the following requirements:

• A management device (PC or laptop).

• An external USB storage device with one of the following 16-bit or 32-bit file allocation table (FAT) file systems:

  • DOS 3.0+ 16-bit FAT (up to 32 MB)

  • DOS 3.31+ 16-bit FAT (over 32 MB)

  • FAT32

  • FAT32, LBA-mapped

  • 16-bit FAT, LBA-mapped

BOOTP, RARP and DHCP are the supported protocols for acquisition of IP address of the router and TFTP, FTP, and HTTP are the supported protocols for downloading the configuration file from an external server URL on which the configuration file is stored.

The following operations occur during autoinstallation in hybrid mode on ACX Series routers:

1. When a new ACX Series router is powered on for the first time, the router performs the following autoinstallation tasks: The router boots the Junos OS image. The management process (mgd) is invoked and it determines whether a valid configuration exists on the router’s Flash memory. If a valid configuration is not present on the router, it loads and commits the factory-default configuration.

2. If the factory-default configuration contains the autoinstallation configuration stanza at the [edit system] hierarchy level, the autoinstallation process is triggered.

3. The autoinstallation process detects whether an external USB storage device is connected to the router and examines whether the USB device contains a valid configuration file. If the USB storage device contains a configuration file named juniper-config.txt, the router reads the juniper-config.txt file and commits the configuration.

4. If the juniper-config.txt file on the external USB storage device contains continue-network-mode statement, the configuration is treated as partial configuration. The autoinstallation process uses this partial configuration to obtain the complete configuration file from a server on the network. At this stage, the router completes the USB mode of the autoinstallation procedure and switches to the network mode of the autoinstallation procedure.

   Note:

   The continue-network-mode statement must be present in the autoinstallation stanza at the [edit system autoinstallation] hierarchy level of the juniper-config.txt file.

5. After acquiring the partial configuration from the juniper-config.txt file, the configuration discovery procedure is initiated. For all physical Ethernet interfaces that transition to the up state, the autoinstallation process verifies whether autoinstallation is configured on that Ethernet interface. The autoinstallation process starts IP address acquisition mechanism to obtain IP address of the server followed by the configuration file retrieval mechanism.

6. For the interfaces that take part in the autoinstallation process, the IPv4 address discovery procedure is triggered. The new ACX Series router sends out DHCP, or BOOTP, or RARP requests on each connected interface simultaneously to obtain an IP address. The interfaces statement in the autoinstallation configuration stanza at the [edit system] hierarchy level in the factory-default configuration also specify the protocols to be used for IPv4 address discovery. If the interfaces statement is not configured, all the applicable protocols for an interface are used to send out requests on each connected Ethernet interface.

7. If an IPv4 address cannot be retrieved, the autoinstallation process starts the DHCP server on all participating interfaces (assigns static IP address in the form of 192.168.x.1 to allow a management station to connect to the router for manual configuration) and terminates the autoinstallation procedure.

8. If a DHCP server responds, it provides the router with some or all of the following information:

   • An IP address and subnet mask for the autoinstallation interface.

   • The location of the TFTP server on which the configuration file is stored.

   • The name of the configuration file to be requested from the TFTP server.

   • The IP address or hostname of the TFTP server.

   • If the DHCP server provides configuration server hostname, a DNS server must be available on the network to resolve the name to an IP address.

   • The IP address of an intermediate router if the configuration server is on a different LAN segment from the new router.

   Note:

   To use HTTP or FTP server, you need to specify the URL of the configuration server under the [edit system autoinstallation configuration-servers] hierarchy level.

9. After an IPv4 address is retrieved for an interface, the interface is configured with that address and the autoinstallation process starts the configuration file discovery procedure. The autoinstallation process on the router attempts to download a configuration file in the following methods:

   1. If the configuration file is specified as a URL, the router fetches the configuration file from the URL by using HTTP, FTP, or TFTP depending on the protocol specified in the URL.

   2. If the DHCP server specifies the host-specific configuration file (either through file field option or boot file option or host name), the router uses that filename in the TFTP server request. In case of host name, the configuration filename is hostname.conf. The autoinstallation process on the new router makes unicast TFTP request for hostname.conf. If this attempt fails, the router broadcasts the request to any available TFTP server for the configuration file.

   3. If the new router is unable locate the configuration file, the autoinstallation process unicasts or broadcasts TFTP requests for a default router configuration file called network.conf, which contains hostname-to-IP address mapping information, to attempt to find its hostname.

   4. If network.conf contains no hostname entry for the new router, the autoinstallation process sends out a DNS request and attempts to resolve the new router’s IP address to a hostname.

   5. If the new router can determine its hostname, it sends a TFTP request for the hostname.conf file.

   6. If the new router is unable to map its IP address to a hostname, it sends TFTP requests for the default configuration file router.conf.

      Note:

      The autoinstallation process makes a maximum of three attempts to retrieve the configuration file by repeating the methods listed above (b to f). In case the autoinstallation process fails to retrieve the configuration file after three attempts, the autoinstallation process goes to start state.

   7. After the new router locates a configuration file on a TFTP server, autoinstallation downloads the file, installs the file on the router, and commits the configuration.