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DDN MGT Bulletin 73              DCA DDN Defense Communications System   
24 May 90                        Published by: DDN Network Info Center
                                     (NIC@NIC.DDN.MIL)  (800) 235-3155


                        DEFENSE  DATA  NETWORK

                         MANAGEMENT  BULLETIN

The DDN MANAGEMENT BULLETIN is distributed online by the DDN Network
Information Center under DCA contract as a means of communicating
official policy, procedures and other information of concern to
management personnel at DDN facilities.  Back issues may be read
through the TACNEWS server ("@n" command at the TAC) or may be
obtained by FTP (or Kermit) from the NIC.DDN.MIL host [192.67.67.20]
using login="anonymous" and password="guest".  The pathname
for bulletins is DDN-NEWS:DDN-MGT-BULLETIN-nn.TXT (where "nn" is the
bulletin number).
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                      PSN 8.0 CONGESTION CONTROL
 

SUMMARY:
 
The Defense Communications Agency (DCA) enabled the PSN 8.0 congestion
control mechanism on the MILNET on 19 May 1990 at 0900 EDT.
 
BACKGROUND:
 
The Defense Communications Agency began a phased deployment of Packet
Switch Node Software Release 8.0 (PSN 8.0) on the MILNET in August
1989.  PSN 8.0 contains several improvements including, most notably,
congestion control.  Congestion control improves subscriber host
utilization of the subnetwork by alleviating subnetwork congestion.
PSN 8.0 manages subnetwork congestion by controlling the data input
rate from hosts attempting to use congested subnetwork resources.
 
DCA ACTION:

At this time, all MILNET Packet Switch Nodes contain PSN 8.0.  On 19
May 1990 at 0900 EDT, DCA enabled the PSN 8.0 congestion control
mechanism on MILNET.  Contingency plans have been in effect and DCA
will disable congestion control for anomalous subnetwork activity or
subscriber host degradation verified as relating to congestion
control.
 
SUBSCRIBER ACTION:
 
No subscriber action is necessary for the enabling of congestion
control.  DCA anticipates that neither subscribers' hosts nor
subscribers' perception of network utilization will be affected.
Subscribers should follow their normal operational and trouble
reporting procedures.