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DDN MGT Bulletin #110             DISA DDN Defense Communications System   
8 December 1992                   Published by: DDN Network Info Center
                                      (NIC@NIC.DDN.MIL)  (800) 365-3642


                        DEFENSE  DATA  NETWORK
                         MANAGEMENT  BULLETIN

  The DDN MANAGEMENT BULLETIN is distributed on-line by the DDN Network
  Information Center under DISA 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 [192.112.36.5]
  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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              NSFNET T-1 Changeover to T-3 Backbone

Ref:  DDN Mgt Bulletin #99, Change of Architecture for MILNET/NSFNET

This message provides important guidance and status information concerning
communication between MILNET and the non-DoD Internet (i.e., NSFNET.)

1. On Wednesday, Dec. 2, the last NSFNET T-1 router was moved to
   connect to the NSFNET T-3 (140.222.0.0) backbone service.  As of 12:01
   a.m. EST on Wednesday, Dec 2, the T-1 NSFNET Backbone (129.140.0.0) no
   longer exsists.  With its passing, DDN customers using gateways/
   concentrators are requested to change their default IP network to 
   140.222.0.0 vs. 129.140.0.0. 

   DEFAULT ADDRESS 129.140.0.0 WILL BE REMOVED 1 FEBRUARY 1993, SO PLEASE
   MAKE THE CHANGE BEFORE THIS DATE TO PREVENT UNNECESSARY DELAYS IN
   INTERNET TRAFFIC.

2. In an effort to provide a smooth transition to subscribers exchanging
   traffic between MILNET and NSFNET, a temporary routing mechanism has
   been implemented to interconnect MILNET and NSFNET via the FIX-East and
   FIX-West Internet Protocol routers (IPRs) on the DISN-NT Pilot Network.
   For address resolution, a static route pointing traffic destined for
   network 129.140.0.0 to network 140.222.0.0 has been added at each
   FIX-point.  Note that this routing mechanism is only temporary; it will
   be removed as of 1 February, 1993. 

3. MILNET hosts will continue to statically default to the IPR closest
   to them, and MILNET gateways will obtain a dynamic default for NSFNET
   traffic via EGP updates from the Mailbridges. The default IPR will now
   be advertised as the next hop to both the default NSFNET backbone
   network, 140.222.0.0, and to network 0.0.0.0 .

4. In addition to the Ciscos at FIX-West and Ft. Detrick, the Cisco IPRs
   on the Pilot Network are default gateways providing store-and-forward
   functionality for MILNET users.  MILNET gateways will obtain the proper
   default IPR via EGP updates with the Mailbridges.

5. Mailbridges now provide routing information about MILNET networks,
   one NSFNET backbone network (140.222.0.0), and network 0.0.0.0 in their
   EGP updates. In addition, the Mailbridges are configured with a list of
   IPRs to use as default gateways for traffic destined for NSFNET.  The
   default IPR is advertised as the next hop to BOTH network 140.222.0.0--
   the new T-3 NSFNET backbone network--and to network 0.0.0.0.

6. DISA point of contact is Mr. McDaniel: 
   (DSN) 222-7580
   Coml (703) 692-7580
   E-mail:  cmcmgr@ddn-conus.ddn.mil