Robert, I noticed you had posted some additional questions. I hope the following is helpful.
<Can you configure 2 tcp stacks to use the same IP address and/or OSA?> An OSA can be shared by multiple TCPIP stacks. An IP address can be moved between TCPIP stacks, but can only be assigned to one stack at a time. There is a redbook that has some good information on different possible configurations - SG24-5948-04 OSA-Express Implementation Guide. <Can you/should you configure one host name that has multiple IP addresses assigned to it?> A host name should be associated with only one IP address. However, one can have multiple IP address/host name pairs associated with one TCPIP stack. The decison on using multiple IP addresses would depend on what requirements there are for separating traffic and moving applications. For instance, VIPA separates the IP address from the hardware. Two OSAs each with their own IP address could provide redundant paths to the same VIPA on a single TCPIP stack. There are various scenarios for moving IP addresses to alternate systems with dynamic VIPA and DVIPA. A good resource is the redbook SG24-7341-00 Communications Server for z/OS V1R8 TCP/IP Implementation Volume 3: High Availability, Scalability and Performance. The OSA-Express Implementation Guide has an Appendix on ARP takeover which I found helpful. ARP takeover is what we implemented here. The configuration used is based on the hardware configuration and the business requirements at your site. For IPV4 links, there is a relationship between links, IP addresses and host names that you will need to know if you are using DB2 or anything else that uses the gethostid function. This may not apply to your environment, but I mention it here because it is hard to track this down in the manuals. In the TCPIP profile there is a parameter "PRIMARYINTERFACE" which defaults to the first link in the HOME statement. The IP address assigned to this link in the HOME statement is used to get the host name. There is discussion of local host name files in the IP Configuration Guide. We use a sequential file that is referenced by DEFAULTIPNODES in the resolver configuration file. If this is not set up correctly, the resulting error message in DB2 states that "gethostid failed". <For my purposes (testing apps to convert from CA to IBM), is my system configured ok w/ 2 IP's and host names? Or would it be better another way?> Yes, as long as there are no requirements for redundancy or movement of IP addresses. Even if redundancy will be added later, it is not needed for testing applications. One other thing - if you are using QDIO with OSA-Express2 on a z890, z990, or z9 EC or BC Processors, there is an IBM flash that advises turning off a new feature that was added by APARs to z/OS 1.6 in 2006. I do not know at what release it became part of the base code. Because of unresolved issues IBM advises disabling the feature by coding NOSEGMENTATIONOFFLOAD on the GLOBALCONFIG statement in the TCPIP profile. The title of the Washington Systems Center Flash is "OSA-Express2 Segmentation Offload". Sheila Weissborn Ohio Casualty Insurance ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
