sdp – secure datagram protocol
bind -a #Espec /net
unhandled troff command .sp
device provides the interface to the Secure Datagram Protocol (SDP).
SDP (un)compresses and (de-)encrypts packets.
is an integer from 0 to 15 identifying a stack.
Each stack is independent of all others:
the only information transfer between them is via programs that
mount multiple stacks.
Normally a system uses only one stack.
However multiple stacks can be used for debugging
new networks or implementing firewalls or proxy
The top level directory contains a
file, and subdirectories numbered from zero to the number of connections
opened for this protocol.
file reserves a connection. The file descriptor returned from the
will point to the control file,
of the newly allocated connection.
returns a text
string representing the number of the
Connections may be used either to listen for incoming calls
or to initiate calls to other machines.
A connection is controlled by writing text strings to the associated
After a connection has been established data may be read from
and written to
A connection can be actively established using the
message (see also
A connection can be established passively by first
to bind to a local port and then
to receive incoming calls.
The following control messages are supported:
Accept an incoming encrypted connection on
Initiate a new encrypted connection on
typically a UDP
Randomly drop approximately one of every
thus simulating network errors.
to decrypt incoming packets.
to encrypt outgoing packets.
Robust Data Compression of Network Packets ,
Sean Dorward and Sean Quilan, Bell Labs, Lucent Technologies,