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Re: UCX Communication Error

 
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C Ravi
Occasional Advisor

UCX Communication Error

I am working on a VAXStation 4000-60. Open VMS Version 7.1 and DIGITAL TCP/IP services for OpenVMS Version V4.2

I am having problem with communication with an external device.

The IP of my machine is 192.168.1.1 with subnet mask 255.255.255.0.

The IP of the external device is 192.168.1.3 with subet mask 255.255.255.0

when i try to ping to this device it gives an error.

ucx>ping 192.168.1.3
%UCX-I-LOOPINACT, 192.168.1.3 does not respond.

the arp details show

ethernet internet host name ARP status
192.168.1.3 HDL01 INUSE

Ping to the localhost and the machine IP works.

What could be the problem?
15 REPLIES 15
Karl Rohwedder
Honored Contributor
Solution

Re: UCX Communication Error

Does the other way round functions? Is there some network hardware inbetween blocking ping?
Are other TCPIP services functioning?
What is 'external device'?

regards Kalle
C Ravi
Occasional Advisor

Re: UCX Communication Error

No there is no network device in between. The device i am talkin about is an Highway Data link, which is used in plant network. But the device itself is working, as it gets configured using COM port communication.
Volker Halle
Honored Contributor

Re: UCX Communication Error

$ UCX SHOW ARP should also give you the ethernet MAC address in column 1, you did not post that information, so we must believe, that the information is NOT available ! That means, that there was NO ARP response from the external device !

Can you be sure, that sending and receiving ethernet packets via the LAN interface does work at all ? Is there anything else connected to that network, with which your system can communicate ? Pinging localhost and the local node IP address does NOT tell you, whether the LAN interface can actually send/receive patckets at all.

Check the LAN interface counters:

$ ANAL/SYS
SDA> SHOW LAN/COUNTER
...
SDA> EXIT

Does the external device have any counter information (like received/sent packets) ? Do these counters increase ?

Volker.
C Ravi
Occasional Advisor

Re: UCX Communication Error

No there is no other device connected to this machine, except the one i mentioned before.

I checked the Lan counters, where the received counter value is zero in all cases, but the sent counter shows some value.

Also I can see 8 ESA devices.
Volker Halle
Honored Contributor

Re: UCX Communication Error

If the SENT counters are non-zero, this indicates, that the LAN interface is a least able to send data. If the RECEIVE ounters are 0, it indicates, that no ethernet packets are being received at all.

The fact that you 'see 8 ESA devices' only indicates, that multiple protocols have been started on physical interface ESA0. SDA> SHOW LAN will show you the various protocols.

You now need to look at the counters of the external device. Does it receive any packets ? Does it send any packets ?

Can you connect any other TCPIP-capable device on that 'LAN' ? Maybe your laptop with the correct IP address instead of the 'external device' ?

Volker.
C Ravi
Occasional Advisor

Re: UCX Communication Error

The problem is the external device, is a highway data link, used in plants, this acts as a switch, and hence i cannot check, whether this recives any data or not.

Also i cannot connect my laptop as the Vaxstation uses BNC cable for ethernet communication.

Is there any other way?
C Ravi
Occasional Advisor

Re: UCX Communication Error

Also while configuring the Highway Data link, it asks for the IP address of the Vaxstation and also for the ethernet_address. I provided the ethernet address of the interface(SE0).

But this address is different from the ethernet address of ESA0 which is the ethernet device?


Volker Halle
Honored Contributor

Re: UCX Communication Error

So this is a NEW installation, right ?

There may be 2 MAC adresses involved with a network interface, the HW MAC address (ROM on interface) and the current MAC address, which may have been changed, if DECnet has been started on the interface !

$ ANAL/SYS
SDA> SHOW LAN/FULL

will show you both the hardware MAC address and the current MAC (physical) address as:

Physical address AA-00-04-00-9F-C5 Hardware address 00-12-3F-7D-96-A2

Volker.
C Ravi
Occasional Advisor

Re: UCX Communication Error

Yes, i can see two address,

Physical address AA-00-04-00-14-28

Hardware address 08-00-2B-34-55-4E

Through which address should the communication take place?