DEVICE ADMINISTRATION

Terms:

DCE – Data communications equipment:   modems

DTE – Data terminal equipment:  the serial ports on terminals & computers

Note:  In RS-232 standard, DTE uses pin 2 to transmit data & pin 3 to receive, DCE does the reverse.

RS-232 standard – a standard for the function of the (up to) 25 pins found on serial connections.

serial port – a port that uses RS-232 standard

(Solaris 7 systems have serial ports a & b [/dev/term/a & /dev/term/b])

modem – converts digital data to & from electrical analog signals

null modem cable – allows two DTE devices to communicate via serial ports

data carrier detect – connection established (RS-232 pin 8)

port monitor program – monitors RS-232 circuits on it’s serial ports and provides info to applications

Modem Access Modes – Three Configurations

1.        Inbound – answers incoming calls

2.        Oubound – makes outgoing calls

3.        Bidirectional – both answers incoming and makes outgoing calls

Service Access Facility – SAF

SAF provides services for serial ports & network connections. Under  the  SAF, systems may access services using a variety of port monitors, including ttymon, the listener, and port monitors written expressly  for a user's application.

SAF consists of two levels: the top administrative level is concerned with port monitor administration, the lower level with service administration.

SAF Terms:

service-  a service is a process that is started, these processes monitor & setup connections using serial ports & network interfaces.

port - an externally seen access point on a system, a port may be an incoming phone line, serial port, etc.

Service Access Controller – sac – the controlling process (the upper-level program of SAF), starts & controls the lower-level SAF programs (port monitors)

·         sac daemon is started in /etc/inittab  (system levels 2, 3 & 4)

·         reads:  /etc/saf/_sysconfig         the sac configuration file

·         reads:  /etc/saf/_sactab               lists port monitors to start

Port Monitors – manage & monitor ports (lower-level SAF program), port monitors are processes that are responsible for monitoring a set of incoming ports on a machine. 

·         A port monitor's major purpose is to detect incoming service requests and to dispatch them appropriately. 

·         Some examples of port management are setting the line speed on incoming phone connections, binding an appropriate network address, reinitializing the port when the service terminates, outputting a prompt, etc.

·         A port monitor's administrative file is named /var/saf/pmtag/_pmtab (where pmtag is the tag of the port  monitor); _pmtab is maintained by the pmadm command in conjunction with a port monitor specific administrative command (ie ttyadm for ttymon, nlsadmin for listen)

·         Port Monitors:

·         ttymon – monitors serial ports, connects a specified service to a port, uses /etc/ttydefs for communications settings (baud rate, etc.).  {Default tag is zsmon}

·         listen – network listener daemon, this process ``listens'' to a network for service requests,  accepts requests when they arrive, and invokes servers in response to those service requests. {Default tag is tcp}

SAF Commands

·         sacadm – admin command for the SAC (add, remove, start, stop port monitors)

·         pmadm –admin command for the Port Monitors (add, remove, enable, disable services) (modifies _pmtab file)

·         ttyadm – formats ttymon data for the pmadm & sacadm commands

·         nlsadmin – formats listener data for the pmadm & sacadm commands

ADMINTOOL

Adding a Terminal

1.        Select Browse -> Serial Ports

2.        Click on the port

3.        Select Edit -> Modify

4.        For Template select Terminal – Hardwired

5.        Select the baud rate

6.        Modify the name in the Terminal Type field if desired (terminfo entry)

7.        Click on OK

Adding a Bidirectional Modem

1.        Select Browse -> Serial Ports

2.        Click on the port

3.        Select Edit -> Modify

4.        For Template select Modem – Bidirectional

5.        Select the baud rate

6.        Modify the name in the Terminal Type field if desired (terminfo entry)

7.        Click on OK

TIP COMMAND

·         The tip utility establishes a full-duplex terminal connection to a remote host.  Once the connection is established, a remote session using tip behaves like an interactive  session on a local terminal.

·         Typed characters are normally transmitted directly to the remote machine (which does the echoing as well).

·         Escape commands starting with a tilde (~) can be used to perform some functions (like drop connection, file copy, BREAK, etc.)

·         Uses /etc/remote file which contains entries describing  remote  systems & line speeds used by tip.

·         Configured by the .tiprc file in the user’s home directory which is read when tip command is used.

·         Examples:

                Using device:        tip /dev/term/b

Using hostname:   tip dbserver  

                Using phone #:      tip 703-855-5555

/etc/remote           has descriptions of remote hosts such as serial port to use, baud rate, modem settings,

& phone number.

/etc/phones           if the phone number in the /etc/remote file is an @ symbol, tip uses the /etc/phones file

which associates hostnames with a phone number.   Each phone number found for a system is tried until either a connection is established, or an end of file is reached.

Format of lines:  system-name phone-number               

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