PSN 6.0 Battle Scars


Ron Stoughton (rms@ACC-SB-UNIX.ARPA)
Tue, 17 Jun 86 00:10:09 pdt


        Packet Content

        1 TCP/IP Header [Datagram n, Len=576], Data, M=1
        2 Data, M=1
        3 TCP/IP Header [Datagram n+1, Len=576], Data, M=1
        4 Data, M=1
        5 TCP/IP Header [Datagram n+2, Len=576], Data, M=1
        6 Data, M=1
        7 TCP/IP Header [Datagram n+3, Len=576], Data, M=1
        8 Data, M=1
        9 TCP/IP Header [Datagram n+4, Len=576], Data, M=1
        10 Data, M=1
        . .
        . .
        . .

The proper sequence should have been:

        Packet Content

        1 TCP/IP Header [Datagram n, Len=576], Data, M=1
        2 Data, M=1
        3 Data, M=1
        4 Data, M=1
        5 Data, M=0
        6 TCP/IP Header [Datagram n+1, Len=576], Data, M=1
        7 Data, M=1
        8 Data, M=1
        9 Data, M=1
        10 Data, M=0
        . .
        . .
        . .

The above two problems are similar in that they both occur at the
packet level and the data source is much faster than the data sink.
However, since one occurs in HDH and the other in X.25, I don't
expect they are related.

Battle #3

We are still investigating this problem, but some preliminary info
may be of interest to the community. We have multiple sites connected
with identical IF-370/DDN interfaces to PSN 6.0 IMPs. All but one
are running without problems except as noted above. The exception is
1ISG which is unable to run at all due to the IMP rejecting our call
request packets. The indication from the IMP is that our precedence
facility code is being administratively disallowed. Both ACC and BBN
have compared the configuration parameters of the various IMPs and
found them to be the same. In order to eliminate our hardware as the
culprit, we canned some X.25 sequences on the Chameleon and fired them
at the IMP to see what it would do. As expected, it accepted call
requests as long as they didn't contain the precedence facility. One
would conclude that there is an obvious difference in the configuration
of the IMP port to which we are attached, but so far it has eluded BBN.

Anyone with similar X.25 battle stories is encouraged to share them
with the tcp/ip community so that we don't debug the same problem
multiple times.

                        Ron Stoughton
                        RMS@ACC-SB-UNIX.ARPA



This archive was generated by hypermail 2.0b3 on Thu Mar 09 2000 - 14:36:34 GMT