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communication problem after upgrade OS version

gunalan_1
Occasional Advisor

communication problem after upgrade OS version

hai,

My current system is Digital Alpha Server 1000A (5/333) running on OS Open VMS v7.1 and oracle7.But now i plan to migrate to Compaq Alpha DS10 Server. In order to migrate i have to upgrade my OS to Open VMS v7.1-2 with some new patches. But i have faced problem unable to communicate with our PLC using my VIP process after the upgrade.My VIP process is C code program which is communication handler process to manage message exchange between my system and the ABB PLC system. i attched the VIP c code for your reference and this is the error massage :

while(nleft > 0 && nprob < 100)// Try to wait for max 100 times
{
if (!ioctl(fd, FIONREAD, &ninbuf)){
msg_signal("EVIP readn ioctrl error = %s", strerror(errno));
return -1;
}

Please help me on this matter.

Thanks n regards
Gunalan
15 REPLIES
Karl Rohwedder
Honored Contributor

Re: communication problem after upgrade OS version

Gunalan,

is any error message displayed, is the rest of the network functioning correctly?

regards Kalle
Robert Gezelter
Honored Contributor

Re: communication problem after upgrade OS version

Gunalan,

The first question is whether you installed 7.1-2 on a clean disk, or applied an update to the existing system disk.

7.1-2 is a collection of patches, while problems with patches do happen, it is not the most likely possibility.

If you created a new system disk, a good possibility is that something either was omitted from the configuration, or did not start properly during system startup.

Is the system disk new (or did you upgrade an existing system disk)?

What else is (or is not) working as expected?

- Bob Gezelter, http://www.rlgsc.com
Hoff
Honored Contributor

Re: communication problem after upgrade OS version

That there is a failure when polling for incoming characters in a TCP message stream implies a rather fundamental error within the environment.

Is IP configured and started in this environment?

Since this is IP, do mechanisms such as ping show connectivity with the ABB PLC controller?

And as others have requested, what's the error (if any)? I might well assume the result here is a no-data condition; that there's nothing arrived from the ABB PLC.

I am assuming the polling loop used is to deal with the fact that TCP is not a datagram protocol and that it can segment arriving character data in interesting ways. I didn't look at the provided C code in detail to see if it included re-assembly, but that you can and will receive partial messages can potentially be a surprise -- the ABB PLC or any other IP data source might well write a single unit of a couple of hundred bytes into its TCP socket, and the data can conceivably arrive as one message, or as a couple of hundred one-byte "messages". Combine this with a read buffer that doesn't get cleared and you can see all manner of "torn" messages and degenerate behavior. (This is not specific to OpenVMS, this is how TCP works, and how it is supposed to work.)

The specification of the address of the address for the ioctl looks a bit weird in the polling routing. I'd expect ioctl( fd, FIONREAD, ninbuf); as it appears that ninbuf is already a pointer. I'd confirm this.

Polling itself must be handled quite cautiously, and that solution can be very sensitive to changes in performance. An AlphaServer DS10 executes its polling loops rather faster than an AlphaServer 1000A series box does, for instance. It might well finish its polling before the ABB PLC sends its data, where the older system was slow enough that the polling windows lined up.

Moving to AST-based code can avoid the need for polling, but that's likely going to involve a reorganization of the existing C code. The expedient solution is to increase the polling count to offset the faster system.

I'd probably enable tracing in the code, such that the trace2 routines are active. If conditionalized through a header file, you can avoid the need to re-comment these routines when you next need to disable tracing.

I spent some time some time ago providing C and PLC-related and communications work. I feel your pain. :-)

Stephen Hoffman
HoffmanLabs
gunalan_1
Occasional Advisor

Re: communication problem after upgrade OS version

Hi, to all, sorry for late reply because i was in medical leave.

I restore the system backup from Alpha server 1000A(5/333) in to DS10 server on a new disk.
Then i upgrade from Open VMS v7.1 to v7.1-2. All the network configuration i follow as remain no changes has been done. All the setting are correct at the time. But i faced problem even to ping to the PLC system. Is it anything wrong with the patches that i applied? Because its no problem when i using V7.1.. Even i tried used another server digital Alpha 800 with v 7.1 and its run with out any problem. The problem happened after i upgrade to 7.1-2. To gather with this i attached the upgrading manual that was prepared by my vendor.

thanks for ur kind feedback.

regards,
gunalan
Karl Rohwedder
Honored Contributor

Re: communication problem after upgrade OS version

Just a simple question (since even the PING doesn't work): Did you take into account that a DS10 has 2 Ethernet interfaces, perhaps your configuration is for EWA0 and you plugged in the network cable at EWB0?

regards Kalle
gunalan_1
Occasional Advisor

Re: communication problem after upgrade OS version

hello kelle,

i configure for EWA0, and i attached the TCP/IP confuguration manual that i have for your reference.

thank you,

regards,
gunalan
Karl Rohwedder
Honored Contributor

Re: communication problem after upgrade OS version

Does MC LANCP SHOW DEVICE EWA0/COUNTER show traffic on this interface (in comp. to EWB0)?

regards Kalle
gunalan_1
Occasional Advisor

Re: communication problem after upgrade OS version

hi,,

i checked the MC LANCP SHOW DEV EWA0/COUNTER

its shows : 3 Carrier Check Failures.

what it means? and need any futher action?


regards

guna.
Steven Schweda
Honored Contributor

Re: communication problem after upgrade OS version

> its shows : 3 Carrier Check Failures.

What about the traffic? Around here, for
example:

[...]
Device Counters EWA0:
Value Counter
----- -------
10648228 Seconds since last zeroed
17955165009 Bytes received
20029364134 Bytes sent
65972293 Packets received
97530743 Packets sent
[...]
1 Carrier check failures (22-SEP-2006 15:32:36.06)
[...]

While, for an unused PCI card:

[...]
Device Counters EIA0:
Value Counter
----- -------
10648441 Seconds since last zeroed
0 Bytes received
0 Bytes sent
0 Packets received
0 Packets sent
[...]


Can you do anything with IP on this system
with any other system on your network, or is
talking to the PLC the only problem?

A plain text attachment would be much easier
to read than a Microsoft Word Document, by
the way.
gunalan_1
Occasional Advisor

Re: communication problem after upgrade OS version

there is a 2 network cards is connected

1) EWA0 which is link to PLC
2) EWB0 which is link to our local PC


Device Counters EWA0:
Value Counter
----- -------
2843 Seconds since last zeroed
0 Bytes received
0 Bytes sent
0 Packets received
0 Packets sent
0 Multicast bytes received
13 Carrier Check failure
* all athers shows 0 value*

only facing problem to talk with PLC program.
sometimes when i ping to my PLC its shows active but after i restart my process
i unable to ping again.
Steven Schweda
Honored Contributor

Re: communication problem after upgrade OS version

> 13 Carrier Check failure

Is that stable or growing?

Sounds as if you don't really have a good
network connection. Bad cable? Bad
hub/switch? What all is between the Alpha
and the PLC? What is the network speed?
What is the EWA0 speed/duplex setting?
Hub/switch speed/duplex setting? PLC
speed/duplex setting?

MCR LANCP SHOW DEVI EWA0 /CHAR

> [...] after i restart my process [...]

Process? Which process?
Karl Rohwedder
Honored Contributor

Re: communication problem after upgrade OS version

It looks as if EWA0 is not connected/configured, since no bytes are sent/received.

regards Kalle
atul sardana
Frequent Advisor

Re: communication problem after upgrade OS version

Dear gunalan,
For communication problem.........i suggest you with some examples....pls try and reply....
First you check all tcpip services is enabled or not in your system after upgrading with command
$ucx show services
Service Port Proto Process Address State

BIND 53 TCP,UDP TCPIP$BIND 0.0.0.0 Disabled
BOOTP 67 UDP TCPIP$BOOTP 0.0.0.0 Enabled
ESNMP 705 UDP ESNMP 0.0.0.0 Disabled
FINGER 79 TCP TCPIP$FINGER 0.0.0.0 Disabled
FTP 21 TCP TCPIP$FTP 0.0.0.0 Enabled
MOUNT 10 TCP,UDP TCPIP$MOUNTD 0.0.0.0 Disabled
NFS 2049 UDP TCPIP$NFS 0.0.0.0 Enabled
NTP 123 UDP TCPIP$NTP 0.0.0.0 Disabled
PORTMAPPER 111 TCP,UDP TCPIP$PORTM 0.0.0.0 Enabled
SNMP 161 UDP TCPIP$SNMP 0.0.0.0 Enabled
SPAGENT 4999 TCP SWCC_AGENT 0.0.0.0 Disabled
SPGUI 4998 TCP not defined 0.0.0.0 Disabled
TELNET 23 TCP not defined 0.0.0.0 Enabled
TFTP 69 UDP TCPIP$TFTP 0.0.0.0 Enabled

if all services is working fine as per ur requirements then check network cards status with command
$show interface
TCPIP> sho inter
Packets
Interface IP_Addr Network mask Receive Send MTU

IE0 10.96.0.21 255.0.0.0 381931285 4107205 1500
LO0 127.0.0.1 255.0.0.0 3325 3325 4096
WE0 85069 0 1500
if any problem in packets received or sent counts then rectify it...

Atul Sardana
I love VMS
gunalan_1
Occasional Advisor

Re: communication problem after upgrade OS version

hai,

i only can test my new server during production stop.The next production stop will be next week. i will feedback after the test.

thank you for kind of feedback,

regards,
gunalan
gunalan_1
Occasional Advisor

Re: communication problem after upgrade OS version

hi, this is the network status after i tested. i think the problem not from my network, its may be from the C code as Mr. Hoff said.


Device Counters EWA0:
Value Counter
----- -------
11141 Seconds since last zeroed
181032319 Bytes received
294270900 Bytes sent
2500121 Packets received
2460168 Packets sent
2299353 Multicast bytes received
138619 Multicast bytes sent
0 unrecognized unicast destination packets
7284 unrecognized multicast destination packet.

*others all 0 values*

UCX>show interface
Interface IP_Addr Network mask Receiv Send MTU

WE0 192.168.2.120 255.255.255.0 2607830 2577985 1500
WE10 138.223.226.142 255.255.255.0 526 876 1500
WE0 127.0.0.1 255.0.0.0 4 16 65535


regards, guna