cec – Coraid Ethernet Console


cec [ –dp ] [ –S srv ] [ –c esc ] [ –e ea ] [ –h host [ –s shelf ] [ interface ]


The cec command uses raw ethernet frames to connect to a CEC server to simulate a serial connection. The client and protocol provide for packet acknowledgement and retransmission. Coraid appliances and Coraid Plan 9 kernels can currently be CEC servers. Each uses CEC to provide console access.
A cec process starts by probing the specified network interface for available CEC servers. The default is /net/ether0 . Only one cec process may be run per ethernet interface. The –S flag posts its argument to /srv to allow sharing. If the server is specified with the –b, –h, or –s flag, the connection will proceed immediately upon discovery of the first CEC server with the specified address. Otherwise, a selection prompt will be displayed showing the discovered CEC servers available for communication. Unless the –p flag is specified, cec exits if no matching servers are found.
0 5 003048865f1e shelf5
The selection prompt accepts
n     Connect to server n (from the first column),
p     Probe the interface again, and
q     Quit.
Note the selection number is not the shelf address but the cec–generated sequence number printed in the leftmost column.
Once connected to a cec server, entering the escape sequence will drop the user into an escape prompt where the user may type 'q' to quit the connection, 'i' to send the escape sequence across the connection, or '.' to continue the connection. The escape sequence is printed on connection. If the connection is unexpectedly lost, the initial probe process outlined above is rerun.

c esc       Set the escape caracter to ctl– esc. The default setting is ctl–\.
d          Output debugging information.
e ea        Connect to the server with ethernet address ea.Thisoptionimplies –p.
h host      Connect to the server named host. Note this name may not be the same as the value of /dev/sysname.
p          Persistence. Continue trying to connect even if there are no matching servers. This is useful when connecting to a cpu server before it boots.
s shelf      Connect to the server at shelf address shelf.




The CEC protocol should be integrated with the console server.
CEC should multiplex network connections as /net/tcp does.
Early boot information and very late crash information from servers may be lost due to timing quirks.