Sheila
You should check you understanding of names and IP addresses. The IP address
is the entity that really matters, each one associated with one interface -
even if some interfaces are virtual. There is an "official" host name but
its usage is whatever you like to make of it - in conjunction with the name
server system if used.
If a name is to be associated with a node and the node has multiple
interfaces, necessarily the name, indirectly, is associated with the
multiple IP addresses, each one of which is primarily associated with an
interface.
You've probably noticed we've been flogging the OSA/VIPA topic to death
recently!
I'm not sure Robert is quite ready for dynamic VIPAS just yet! Maybe after
he has performed his "conversion". Also we need to assume he has multiple
LPARs ready to benefit from the wandering dynamic VIPA. I've a suspicion
that when he talked about sharing an OSA between two programs behaving as IP
nodes, both programs were running in the same LPAR.
Because it's really a different topic, I am responding to your gethostid()
point in a separate thread.
Chris Mason
----- Original Message -----
From: "Sheila Weissborn" <[EMAIL PROTECTED]>
Newsgroups: bit.listserv.ibm-main
To: <[email protected]>
Sent: Wednesday, September 05, 2007 7:30 PM
Subject: Re: CA to IBM TCP Conversion
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.
...
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
