Adam, Don't see your problem but we use a mix of z/OS and Linux (SuSE 2.4.17) so can't exactly match your config.
A few basic questions: The Linux guest that "owns" the OSA - does this mean the OSA is not shared at all, and/or have you defined it as PRI router? Are the Hipersockets addresses added to /proc/qeth_ipa_takeover ? Are you using dynamic routing at all (Zebra / gated)? What about MTU sizes and/or are you using Path MTU discovery on all stacks involved? Ciao Mark -----Original Message----- From: Linux on 390 Port [mailto:[EMAIL PROTECTED]]On Behalf Of Adam Thornton Sent: 01 July 2002 16:25 To: [EMAIL PROTECTED] Subject: Strange TCP (?) behavior with OSA-GigE/HiperSockets I've got a situation where I've got a Linux guest owning an OSA-GigE, with (virtual) HiperSockets networks routed behind him. Ping times to the HiperSockets guests are effectively instantaneous. If I ssh to the guest with the Gig-E and then SSH to the guests behind him, *that* interaction is instantaneous. But if I SSH directly to the guests on the HiperSockets, it works but the connection is unresponsive and jerky; it feels like I'm typing over a transatlantic line. Everything gets there eventually but it sometimes takes a few tenths of a second. I'm guessing that this is something to do with TCP buffering packets as they pass from one interface to another, since the problem doesn't exist with ICMP packets. Further I suspect that--since I'm running the SuSE 2.4.7-timer kernel--it may have something to do with TCP not flushing its buffers on each timer tick, since there are no timer ticks. This, however, is a guess which I have not yet attempted to construct a test case for. Has anyone else seen this behavior? Adam
