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fddi_config(8)						       fddi_config(8)



NAME

  fddi_config -	Displays and modifies the Fiber	Distributed Data Interface
  (FDDI) parameters

SYNOPSIS

  /usr/sbin/fddi_config	-i interface_name [-c valid_counter_interval_time]
  [-d] [-l link_error_monitor_threshold] [-p [1	| 0]] [-r
  restricted_token_timeout_time] [-t token_request_time] [-v
  valid_transmit_time] [-x [1 |	0]]

OPTIONS

  -i interface_name
      Changes or displays the FDDI characteristics for interface_name. You
      must provide interface name.

  -c valid_counter_interval_time
      Determines how often the driver counters are updated by the DEFTA
      adapter.	The default is 1 second.  Setting the interval time to zero
      (0) disables counter updates.  (For the fta FDDI interface only.)

  -d  Displays the FDDI	interface parameters you can set.

  -l link_error_monitor_threshold
      Sets the error rate threshold of Link Error Monitor (LEM).  The range
      for the LEM error	rate threshold is an integer power of 10 from 1x10^-5
      and 1x10^-8. The default LEM threshold is	1x10^-8.

  -p [1|0]
      Sets the ring purger state for the specified FDDI	interface.  A value
      of 1 enables the ring purger ability; a value of 0 disables it.

  -r restricted_token_timeout_time
      Sets the Restricted Token	Timeout	parameter, defining how	long a single
      restricted mode dialog can last before being terminated. The range for
      this parameter is	from 0 to 10000	milliseconds. The default value	is
      1000 milliseconds.

  -t token_request_time
      Sets the Request Token Rotation Time (T_req) for interface_name. T_req
      is used during the ring initialization process to	negotiate a Target
      Token Rotation Time (TTRT) for the ring. The range for this parameter
      is from 4.0 milliseconds to 167.77208 milliseconds.  The default value
      is 8.0 milliseconds.

  -v valid_transmit_time
      Sets the Valid Transmission Time (TVX) timer for a specific FDDI inter-
      face. The	range for the TVX timer	is from	2.5 milliseconds to 5.2224
      milliseconds. The	default	is 2.6214 milliseconds.

  -x [1|0]
      Enables (1) or disables (0) full-duplex operation	for the	fta FDDI
      interface.  If the full-duplex operation is enabled, the interface can
      be in one	of the following states: Idle, Request,	Confirm, or Opera-
      tional.  (For the	fta FDDI interface only.)



DESCRIPTION

  The fddi_config command allows you to	display	all the	parameters you can
  set for a specified FDDI interface and to modify one or more parameters
  depending on your configuration requirements.	If you change a	parameter,
  all parameters, including unchanged ones, are	displayed as confirmation.
  You must be superuser	to use this command.

  Each FDDI interface has a Media Access Control (MAC) entity. As part of
  token	ring initialization, all MAC entities on the ring participate in a
  Claim	Token Process to choose	a Target Token Rotation	Time (TTRT) value.
  In this process, each	MAC entity bids	their own Request TRT (T_req). The
  lowest T_req value is	chosen as the Negotiated TRT (T_neg) or	TTRT for the
  ring.	 Use the netstat -I fza0 -s command to see the Requested TRT and
  Negotiated TRT.

  The TTRT value dictates an approximate, maximum delay	for the	token to make
  a complete loop around the ring. The time it actually	takes for a token to
  complete a loop around the ring is determined	by the stations	on the ring
  and whether or not the token is captured by a	station. If the	difference
  between the time of the last passing of the token and	the current time
  exceeds TTRT,	stations on the	ring may no longer capture the token.

  With small TTRT values, stations cannot hold a token very long on its	loop
  around the ring. This	means that each	station	can transmit only a small
  amount of data, but has the opportunity to capture the token more fre-
  quently and transmit data. With large	TTRT values, stations can hold a
  token	for a longer period of time, enabling them to transmit more data per
  token	capture.  However, each	station	must wait a longer period of time to
  capture a token.  On a heavily loaded	ring this might	not be desirable.

  Each MAC entity also maintains a Valid Transmission Time (TVX) timer to
  recover from transient ring error conditions.	The TVX	timer specifies	the
  maximum amount of time that can elapse without receiving a valid frame or
  nonrestricted	token. When this timer expires,	the MAC	entity assumes that
  the ring is no longer	operational and	initiates the Claim Token process to
  reinitialize the ring.

EXAMPLES

   1.  To show the parameters you can set for the fza0 interface, enter:
	    fddi_config	-i fza0	-d

   2.  To change the TRT value for the fta0 interface to 10.2, enter:
	    fddi_config	-t10.2 -i fta0

   3.  To turn the ring	purger off, enter:
	    fddi_config	-p 0 -i	mfa0



SEE ALSO

  Files: fta(7), fza(7), mfa(7)