Guralp Systems CMG-DCM - Manual (Page 74)

CMG-DCM Data Communications Module
The cryptographic hardware required to produce authenticated CD1.1
streams is installed only in Authentication Modules (AMs). If you do
not have this hardware, you can transmit unauthenticated CD1.1 data
by using a key-bucket code of -1.
prefix : A prefix used to determine where to place generated CD1.1
subframes. For example, a prefix of /data/HPA1. will produce files in
the /data/ directory beginning with HPA1. and followed by a unique
timestamp. Several streams may produce files using the same prefix;
indeed, this is recommended.
Blank lines, and any lines beginning with #, are ignored.
When you have finished editing the file, clicking Save changes will
write the changes to disk. The changes will not take effect, however,
until the CD1.1 service is restarted. You can restart all running CD1.1
services by clicking Restart CD1.1.
5.6 CNSN configuration (cnsn.cfg)
This option is only functional on Authentication Modules (AMs) with
an on-board cryptographic token.
In this system, a signature is generated from incoming data, which is
transmitted together with the compressed data. At the receiving end,
the signature is regenerated and compared with the one sent to
establish authenticity.
To use the CNSN system, you will need to set exactly one
serial.x.service option to cnsn_in, and one to cnsn_out (see Section 6.2,
page 82.) You will also need to edit the file /etc/cnsn.cfg, which
defines the streams.
Each line in /etc/cnsn.cfg describes a single CNSN stream in the
format
method:key-id:high-byte:low-byte:site:channel[:location]
where the fields, separated by colons, are:
method : The compression/signature method, one of
canadian_compression_after_signing,
canadian_compression_before_signing, canadian_as,
canadian_bs, steim_as, steim_bs, or none
key-id : The ID of the key to use for the stream, as used in
74 Issue F