Beacons

Multicast beacon matrices show the status of multicast connectivity between sites and also provide constant traffic of multicast packets to help network engineers with troubleshooting problems.

Multicast beacon matrices are compiled by multicast beacon servers with information sent to them by multicast beacon clients installed in monitoring hosts. Beacon clients send small amounts of traffic to a particular multicast group, and also receive traffic from that group, in order to determine the multicast communication performance between them. At regular intervals, beacon clients also send performance information (e.g. packet loss, delay, etc.) to a beacon server. The beacon server uses this information to compile the matrix that network engineers use to troubleshoot multicast problems.

To aid in detecting multicast connectivity problems between sites connected to the JANET network, a beacon server has been established in the JANET network capable of receiving reports from NLANR/DAST beacon clients operating in an open multicast group. Additionally, JANET also runs a dbeacon server under development, capable of receiving reports from dbeacon clients.

The AGSC encourages Access Grid sites to run a multicast beacon client so that they appear on the JANET beacon matrix (see http://www.beacon.ja.net/ for details), as problems with multicast connectivity in sites running multicast beacons are easier to troubleshoot and resolve.

Ideally, the beacon client will run in the Access Grid node. Alternatively, a different computer within the same network segment can be used, although in some cases this will not be as accurate since the secondary computer may be connected to additional, or even different, network devices (e.g. switches or routers).

Installing the NLANR/DAST Multicast Beacon

For information on how to install and configure a multicast beacon, please see the installation and configuration guidelines. Access Grid users should configure their beacon clients to work with the Access Grid Beacon Matrix. Additionally, they can also configure it to work with the JANET Public Matrix, and if they have frequent international meetings, it may be useful to configure it to work with the Global Beacon Community Matrix as well.

Please note that JANET currently requires sites to run the NLANR/DAST Multicast Beacon version 1.3. Earlier versions of the beacon client will not be able to talk to the JANET beacon server. The NLANR beacon project page can be viewed on http://dast.nlanr.net/Projects/Beacon/. Currently, there is no Windows version available, so beacon clients can be installed on Unix/Linux boxes or on Windows machines running the Linux-like environment Cygwin (see http://www.cygwin.com/ for more information).

Other initiatives: dbeacon

Dbeacon is another multicast beacon tool, currently under development. As opposed to the NLANR/DAST beacon, dbeacon keeps a historic record of monitoring information, which helps troubleshooting problems that occurred in the past. JANET runs a dbeacon matrix on http://www.beacon.ja.net/cgi/matrix.pl.

Information on dbeacon can be found on the dbeacon wiki or on the dbeacon project page.

As with the NLANR/DAST beacon, there is no Windows version of this software.

Please talk to us at the AGSC if you need any further help or information installing your multicast beacon client.