The bcast program uses the protocol stack with only the network layer. It uses the network layer's default port number. The
code is located under the bcast directory.
Multicast Test Program
The mcast.exe program can be used in order to test the performance of IP multicast within a subnet. The multicasts use
a TTL of 1, so they do not travel beyond the originating subnet. The mcast.exe program is invoked as follows:
mcast send|recv send-rate
The first parameter specifies whether this instance of the application is a sender or receiver. There can be only one
sender at a time. The second parameter is only necessary for the sender. This is the rate at which mcasts are placed
on the network, in multicasts per second. Setting this number beyond 1000 will cause the mcast program to multicast as
fast as the network allows. To send 500 multicasts per second, start up the sender on one node:
And one or more receivers on other nodes:
The order in which the sender or receivers are started does not matter. If the mcast program is working properly,
then for the sender the actual send rate will be posted to the screen at regular intervals. The receivers will
post their actual receive rate at regular intervals as well. The mcast program also detects packet losses. If one
or more packets is lost, then the receiver(s) that did not receive the packet will post the sequence number seen and
the expected sequence number. The difference between the two will correspond roughly to the number of packets that
have been lost.
The mcast program does not use the protocol stack. It uses sockets directly in order to provide a comparison with the network
layer of the protocol stack. The code is located under the mcast directory.
Website created by: Ted Bonkenburg ( tjb13@cornell.edu )