On Tue, Jan 27, 2004 at 05:08:11PM -0500, Alan Altmark wrote: > I'm pretty sure that Linux doesn't do IP takeover. The VIPA is registered > in the OSA filters, but the OSA won't respond to ARPs. > Don't confuse VIPA with IP takeover. They are two different things. The > concepts are mixed together on z/OS from an implementation point of view.
You are right Alan, I was wrong inn using the term VIPA takeover. I means : VIPA ARP TAKEOVER , in other word the process of moving the responsibility to answer to ARP request (for VIPA addresses ) from an OSA card to the other one. It is described in APAR PQ26689 for OS/390 IP stack. It is more or less as I described (but it was ICMP used to explore the PLAN, not gratious ARP). I suspect the problem here is that Gbit OSA uses QDIO mode; according http://www.redbooks.ibm.com/redbooks/pdfs/sg245948.pdf in QDIO mode an OSA card answers to ARP request by itself, having IP addresses registered by the IP stack. In the above redbook the process of ARP takeover is described (is this what you mean for IP takeover ?). In the above radbook a reference to spantree exists. I don't know if it applies to Lucius's problem, and I don't whanto to add confusion, but it can perhaps help. My idea is that Lucius configuration (2 OSAD devices on the same physical LAN, VIPA Ip address in the same IP network as the interfaces) can have some problem if LINUX is not able to move the VIPA ARP responsibility from an interface to another one. Probably Adam's option (OSPF) could work better , being less easy to implement. I am very interested in understand how LINUX works in Lucius's configuration. Franco Mignogna franco_mignogna@ it.ibm.com
