US Robotics USR2410 Manual de usuario descargar pdf (Pagina 45)

Table 6-1: Mesh Start Beep Sequences

Configuration Step Corresponding Beep Sequence

Meshstart startup 4 beeps, increasing pitch

Configure mesh wireless device 1 beep

Configure client device, if configured 2 beeps

Start Click 5 beeps, increasing then decreasing pitch

One of the following commands failed 2 beeps, decreasing pitch.

As the network was being debugged, changes to the configuration of the machines were made in

the lab and then the machines were deployed for testing. However, once deployed, there was no

way of updating the configurations, besides bringing the machine in question back to the lab. To

solve this problem, functionality was added to attempt to read the CD-ROM drive of the machine.

If at boot up there was a CD-ROM in the CD-ROM drive, the device was mounted for reading,

and the meshstart program checked to see if there was a meshstart.conf file on the CD-ROM. If

the file was present, meshstart used this configuration file instead of the default one. A CD-ROM

could be created with a new configuration, and deployed simply by rebooting the machine in

question with the new CD-ROM in the drive. This feature was used multiple times to allow

several configurations, such as using the 802.11g standard instead of the 802.11a standard, or

using a different configuration file for Click Modular Router to modify the behavior of the mesh

router. All source code for these programs can be found in Appendix B

There is one last procedure that meshstart did which helped to alleviate the memory leak

problems with the Madwifi driver. Meshstart called another program named memwatch, which is

discussed in the next section.

6.1.2

Memwatch

Due to the memory leak issue in the Madwifi driver mesh routers would randomly run out of

memory, and crash. It was difficult and time consuming to determine which machine failed, since

it became completely unresponsive. As a temporary solution to allow some stability in the

network, a Perl program called memwatch was created. The program polled the amount of free

memory in the system, and, when it went below 5 Mb, memwatch stopped the Click Modular

Router and unloaded the ath_pci kernel module. By doing this, the memory used by it was

released. When the ath_pci kernel module was unloaded, the wireless device needed to be

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US Robotics USR2410 Manual de usuario Pagina 45