re: PSN patch installed


Michael J. O'Connor (oconnor@sccgate.scc.com)
Wed, 16 Dec 87 20:57:36 EST


Andy,
        First of all, I never received the message I'm replying to.
When Enger asked me about the patch a few minutes ago, I asked him
to forward his copy.

        As for the results of the patch, they looked mixed from our
point of view. Our first retest, using good old twg.arpa, produced the
following output fron Sun's X25 management software:

x25manager: std LCN 3 from 10.4.0.51 ADDED
x25manager: std LCN 0 from 10.4.0.51 REMOVED VC has timed out
x25manager: std LCN 3 from 10.4.0.51 ADDED
x25manager: std LCN 0 from 10.4.0.51 REMOVED VC has timed out
x25manager: std LCN 3 from 10.4.0.51 ADDED
x25manager: std LCN 0 from 10.4.0.51 REMOVED VC has timed out
x25manager: std LCN 3 from 10.4.0.51 ADDED

        Sun's support organization tells me that the "REMOVED VC" message
is printed when the PSN times the circuit out. As opposed to the "Removed
Normal Timeout" message printed when the Sun software times out the circuit.
        Meanwhile the following was being output by ping:

ping -v twg.arpa
PING twg.arpa: 56 data bytes
64 bytes from 1a050049: icmp_seq=1. time=2499. ms
64 bytes from 1a050049: icmp_seq=3. time=3160. ms
64 bytes from 1a050049: icmp_seq=7. time=1480. ms
64 bytes from 1a050049: icmp_seq=10. time=1300. ms
10 packets transmitted

----twg.arpa PING Statistics----

10 packets transmitted, 4 packets received, 60% packet loss

round-trip (ms) min/avg/max = 1300/2109/3160

        Every time the virtual circuit was added, I received a packet from
twg.arpa via 10.4.0.51 (add the circuit 4 times, get 4 packets). We
ran this test a couple of times with similar results (different packet
counts and sequence numbers got through). If I pinged 10.4.0.51 the problem
went away as reported previously.

[7] ping -v 10.4.0.51
PING 10.4.0.51: 56 data bytes
64 bytes from a040033: icmp_seq=3. time=1880. ms
64 bytes from a040033: icmp_seq=4. time=1340. ms
64 bytes from a040033: icmp_seq=5. time=1180. ms
^C
----10.4.0.51 PING Statistics----

7 packets transmitted, 3 packets received, 57% packet loss

round-trip (ms) min/avg/max = 1180/1466/1880

[8] ping -v twg.arpa
PING twg.arpa: 56 data bytes
64 bytes from 1a050049: icmp_seq=2. time=2220. ms
64 bytes from 1a050049: icmp_seq=3. time=1660. ms
64 bytes from 1a050049: icmp_seq=4. time=1520. ms
64 bytes from 1a050049: icmp_seq=5. time=2340. ms
64 bytes from 1a050049: icmp_seq=6. time=1940. ms
64 bytes from 1a050049: icmp_seq=7. time=1300. ms
64 bytes from 1a050049: icmp_seq=8. time=1140. ms
64 bytes from 1a050049: icmp_seq=9. time=1180. ms
64 bytes from 1a050049: icmp_seq=10. time=2219. ms
----twg.arpa PING Statistics----

10 packets transmitted, 9 packets received, 10% packet loss

round-trip (ms) min/avg/max = 1140/1724/2340

        As I type this message I can see other Virtual circuits
thrashing. I assume that whatever service they are trying to
perform (SMTP, FTP) it is being accomplished 1 packet per add/remove
cycle, if at all.
        I'm left with the impression that the patch simply lowered
the PSN virtual circuit timeout value in an attempt to take advantage
of the earlier observation that a packet would come through on each
PSN==>Host VC setup.
        So yes, I believe the problem still exists, although in
a mutated form. Additionally, if not this circuit thrashing,
something is confusing the hell out our X25 circuit management
software. Twice today the manager hung up, refusing to create outbound
circuits or accept inbound ones. The program had to be manually stopped
and restarted. Sun support tells me that their gateway works so I should
contact BBN. It was previously suggested by BBN that I should be
kvetching to Sun. What's a poor user to do?

                                Mike

ps: Bob asked me to mention that not only did I not receive the message,
        it took 10+ hours for him to receive his copy.



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