Network Working Group                                        A. McKenzie
Request for Comments: 208                        Bolt Beranek and Newman
NIC: 7181                                                  9 August 1971
Categories: B.l, C.2
Updates: none
Obsoletes: none


                            ADDRESS TABLES

  Attached is a copy of a revision to Appendix A of BBN Report No.
  1822; the revised version of the Appendix is our first attempt to
  make the list of sites attached to the ARPA Network prospective
  rather than retrospective.  We are adopting this approach because of
  the large number of sites scheduled for attachment in the near
  future, and because many Hosts apparently require a site's address to
  be in some local table before their NCPs will permit communication
  with the site.  Therefore, we urge such Hosts to add the new sites to
  their lists of addresses as soon as possible.  Also, please note the
  address change which will be made at BBN on exactly September first.

  Incidentally, it seems to us that it is irrational for an NCP to
  discard otherwise valid messages, simply because the sender's address
  doesn't appear in a local table.  Similarly, it seems almost as
  irrational for an NCP to prevent a local user from trying to
  communicate with a remote site, the address of which is known to the
  user but not stored in the NCP's tables.
























McKenzie                                                        [Page 1]

RFC 208                      Address Tables                9 August 1971


Report No. 1822                             Bolt Beranek and Newman Inc.

APPENDIX A

IMP AND HOST SITE IDENTIFICATION

  Bit 9-16 of the leader of most Host-to-IMP or IMP-to-Host messages
  define a network address related to the message (these bits are not
  meaningful for message types 1, 2, and 4).  In a Host-to-IMP message
  the network address identifies a particular Host to which the message
  should be delivered.  In an IMP-to-Host message the network address
  identifies the Host from which the message originated.

  A network address consists of six bits (bits 11-16 of the leader)
  which specify an IMP number, preceded by two bits (bits 9-10 of the
  leader) which specify the Host number of a particular Host connected
  to that IMP.  The table below gives the decimal values of IMP number,
  Host number, and network address for each Host currently connected to
  the ARPA Network or scheduled for connection in the near future.
  Scheduled installation dates are also shown for Hosts not currently
  connected; these dates, however, are subject to change without
  notice.

   IMP      SITE     HOST                    NETWORK    SCHEDULED
  NUMBER    NAME    NUMBER       HOST        ADDRESS   INSTALLATION
  ------    ----    ------       ----        -------   ------------
    1       UCLA      0       SIGMA-7           1
                      1       IBM 360/91       65
    2       SRI       0       PDP-10 (NIC)      2
                      1       PDP-10 (Al)      66
    3       UCSB      0       IBM 360/75        3
    4       UTAH      0       PDP-lO            4
    5       BBN       0       DDP-516           5  )   See Note 1
                      1       PDP-10 (A)       69  )
                      2       PDP-1O (B)      133

  Note 1: Prior to September 1, 1971 the BBN PDP-1O (A) will be Host
  number 0 (network address 5) and the BBN DDP-516 will be Host number
  1 (network address 69).  The address change is to be made during the
  day on 9/1/71.











McKenzie                                                        [Page 2]

RFC 208                      Address Tables                9 August 1971


IMP       SITE       HOST                      NETWORK     SCHEDULE
NUMBER     NAME      NUMBER      HOST           ADDRESS   INSTALLATION
------     ----      ------      ----           -------   ------------
 6        MIT          0       Honeywell 645        6
                       1       PDP-10              70
 7        RAND         O       360/65               7
                       1       PDP-1O              71
 8        SDC          O       IBM 360/75           8
 9        HARVARD      O       PDP-1O               9
                       1       PDP-1               73
                       2       PDP-11             137
10        LINCOLN      O       IBM 360/67          10
                       1       TX2                 74
11        STANFORD     O       PDP-1O              11
12        ILLINOIS     O       PDP-11              12
13        CASE         O       PDP-1O              13
14        CARNEGIE     O       PDP-1O              14
15        PAOLI        O       B6500               15
16        NASA/AMES    O       IBM 360/67          16      8/3/71
                       2       TIP                144
17        MITRE        2       TIP                145      8/31/71
18        RADC         O       H 635/645           18      10/5/71
                       2       TIP                146
19        NBS          O       PDP-11              19      11/2/71
20        ETAC         2       TIP                148      11/30/71
21        TINKER       O       418 III             21      1/4/71
22        McCLELLAN    O       418 III             22      2/1/72
23        USC          0       IBM 360/44          23      2/29/72
                       2       TIP                151
24        GWC          2       TIP                152      3/14/72
25        NCAR         O       CDC 7600            25      3/28/72
                       2       TIP                153
30        BBN/TIP      2       TIP                158


















McKenzie                                                        [Page 3]