Description
TCP layer
We will not be concerned about providing reliability, and thus do not
need to provide sequence numbers for packets, etc.
tcptest h1 h2 201 the_payload # usable port numbers are 100-1000
causes a msg to be sent from h1 to h2;
h2 prints when the message is received:
h2 received tcptest from h1 for port 201 the_payload
APP layer
We will assume that there is an ftpd running at every host.
You can have them at routers also, but we will not test that.
An ftpd is only able to receive data, it does not send data.
An ftpd does NOT print any info until a connection is closed,
at which point it prints all the data sent to it on the given
connection.
ftpd_conn h1 h2 201
causes h1 to request a connection to the ftpd at h2:201
ftp_send h1 h2 201 data—-1
ftp_send h1 h2 201 data—-2
cause data to be sent from h1 to to the ftpd at h2:201
which merely prints their receipt
ftp_done h1 h2 201
h1 tells h2 to terminate the conn to ftpd at h2:201
