[Simh] EXT : simh on openvms (to get a VAX on top of an OpenVMS Itanium) >> network issue

[Mark Pizzolato]

Hi Gérard,
Are you running the same version of OpenVMS on both the rx2660 which worked and the rx2880 which didn’t?
I asked if you’ve observed any packets making it to the wire.  Did you check that?
One way or another there may be a problem putting packets on the wire, there may be a problem receiving packets from the wire, or Both.
Dave’s comment:
> Just as a guess, does the newer rx2800 use TOE (TCP Offload Engine) network cards or use jumbo packets? That could change the “standard” Ethernet packet behavior enough that PCAP-VMS may no longer work.
This might indeed be a factor if the kernel interfaces to pass data to the TOE are different than the interfaces which the drivers is using.
The current sim_ether code is completely tolerant of jumbo packets and/or interactions with a TOE as long as the packet capture interface can actually get data (at least for IPv4 traffic, IPv6 is a round-tuit project).
If there is a TOE in the picture, maybe there is a mechanism to disable it which would hopefully get the desired kernel interfaces to be used and let pcap_vms work…

-          Mark

From: Simh [mailto:simh-bounces at trailing-edge.com] On Behalf Of Hittner, David T (IS)
Sent: Monday, March 28, 2016 6:45 AM
To: gérard Calliet <gerard.calliet at pia-sofer.fr>; simh at trailing-edge.com
Subject: Re: [Simh] EXT : simh on openvms (to get a VAX on top of an OpenVMS Itanium) >> network issue

PCAP-VMS is kind of strange software.
OpenVMS provides a PCAP library, which is not a full or complete implementation of the PCAP functionality found on other platforms. It is good enough for Ethernet packet dumping, but was not good enough for full—featured PCAP, which is why PCAP-VMS was written. PCAP-VMS is unsupported software that was written by a Digital/Compaq/HP OpenVMS engineer and depends on some undocumented interfaces in the OpenVMS network drivers to implement functionality. If VSI changed those undocumented APIs, it may have broken PCAP-VMS. You may need to contact VSI support and ask them if any of the network interfaces has changed that might break PCAP-VMS, and what might need to be fixed in PCAP-VMS to work with VSI OpenVMS.
You might also ask them to support a full-featured PCAP library in the future, so that we don’t need PCAP-VMS any more. ☺
Just as a guess, does the newer rx2800 use TOE (TCP Offload Engine) network cards or use jumbo packets? That could change the “standard” Ethernet packet behavior enough that PCAP-VMS may no longer work.
Dave

From: Simh [mailto:simh-bounces at trailing-edge.com] On Behalf Of gérard Calliet
Sent: Sunday, March 27, 2016 6:37 PM
To: simh at trailing-edge.com
Subject: EXT :[Simh] simh on openvms (to get a VAX on top of an OpenVMS Itanium) >> network issue

Hello,
I need help for pcap-vms. I use (vax-)simh on top of OpenVMS (VSI) Itanium i4.
I tested vax-simh (simh 4.0 beta) and pcap-vms on OpenVMS on an Itanium rx2660, and it worked fine.
On OpenVMS i4 (rx2880), with exactly the same configuration, and images, I can see my NICs from the simh prompt (sho eth), I can attach a device (attach xq0 ethn), assign it a mac address, and my VAX-VMS on top of simh sees the emulated device, can send data, but does not receive anything.
Can you give me advice, way of tracing the problem, hypothesis ?
I tried to boot the OpenVMS host in startup_p1 MIN, to test if I get the same problem when there is no network software on the host (like DecNet, or Tcpip), and the problem remains.
I rebuilt the pcap-vms from scratch on the i4 host, and the problem remains.
Do you think there could be an hardware issue, like the NIC which cannot work in promiscuitus mode ?
Any help should be welcomed,

Gérard Calliet
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