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Multicast starts being implanted in RNP2

In 2001, RNP made tests with multicast in a pilot network involving several Points of Presence (PoPs) in the Brazilian academic backbone. The experimental stage served to gather the knowledge necessary to implant the service in all RNP2 backbone, which started being done in March 2002.

Native multicast will be made available in the routers capable of making multicast routing; that is to say, in all the PoPs with 7507 routers. In the other ones, a DVMRP (Distance Vector Multicast Routing Protocol - see RFC 1075) tunnel will be implanted between equipment running mrouted in the PoP and the "nearest" 7507 router in the routing structure of the backbone, according to the explanation given by Adenilson Raniery, a technician in RNP's Engineering and Operation Center (Centro de Engenharia e Operações – CEO). (See beside the list of those who will run native multicast and those who will run tunneled multicast.)

The tendency is for all the PoPs to start operating native multicast in their routers as they replace the hardware and software of these routers by newer versions.

Advantages of multicast

Multicast technology is a network service in which a single data flow can be sent simultaneously to several receivers, which shows advantages when compared to its competitors: the unicast and broadcast technologies. In the unicast transmission mode, the source replicates the data flow as many times as the number of receivers. On the other hand, in the broadcast mode, the data are sent to all the network in an undiscriminated way. In both cases, there is band waste. With the multicast technology, the infrastructure is responsible for transporting the data flow to all the interested receivers, replicating them only when necessary. For this reason, multicast is generally aimed at one-to-many and many-to-many applications.

Among the several applications that can benefit from the use of multicast are: videoconference; distance learning; distribution of software, news and market information; live concerts; database updating; distributed games; concurrent processing; distributed simulations; etc. An example of the use of multicast in RNP2 was the transmission of the course "Professional Development to Middle School Math Teachers," offered by the Institute of Pure and Applied Math (IMPA) between January and February this year. The classes were transmitted from Rio de Janeiro to Campinas, Fortaleza, Recife, Belo Horizonte and Porto Alegre.

RNP's Information Center prepared a page to promote the multicast project (available on http://www.rnp.br/lang/multicast_en/index.html). There, one can find more details about this technology, data of the pilot assembled by RNP, some useful links and a list of NewsGeneration articles dealing with this theme. Furthermore, the page explains how to subscribe p-mcast@rnp, an open discussion list maintained by RNP whose purpose is to debate general topics related to multicast.

[RNP, 04.09.2002]