Thanks, that makes more sense now. Here's an example I show our
clients, which is a modified version of IBM's doc:
https://www.tombrennansoftware.com/notes/hma_diagram.png
I mostly see just 1 port used on the SE's, but sometimes 2 like your
setup. All cables go through switches, as you said. No direct connections.
As I see it, there are a couple of benefits with the design:
#1 The HMC/SE setup with an HMA is no different than with external
HMC's. Same number of cables, same number of switch ports, same number
of IP addresses, same firewall ports, etc. Nothing new to learn.
#2 Existing external (or HMA's on other machines) can be setup in the
same network so that one HMC can see multiple mainframes. Note that
existing HMC's need to be at driver 51 to talk with a z16, and some
older HMC's can't be upgraded to that level.
And thanks for mentioning the ETS ports. That's something new that can
be a surprise. IBM says the benefit there is "one less hop", going
direct instead of through the HMC like previous machines.
On 12/18/2024 11:38 AM, Chicklon, Thomas wrote:
It is possible, or most likely very probable, that HMC to SE traffic goes out
to the switch and back. I really don’t know, nor have I had the network folks
trace it or asked IBM to verify this.
The point I was trying to make is that there is no dedicated cable that loops
between two ports on the HMAs so that the SE and HMC on that HMA can
communicate with each other. All cables that plug into the HMA have the other
ends of the cables all plugged into network switches.
Tom Chicklon
Fifth Third Bank
From: IBM Mainframe Discussion List <[email protected]> On Behalf Of Tom
Brennan
Sent: Wednesday, December 18, 2024 2:09 PM
To: [email protected]
Subject: Re: z16 HMC LAN connections
I'm a little confused. You said no cabling was required between HMC and
SE functions on an HMA. But then you said you have 4 cables in each HMA
- 2 for SE and 2 for HMC, I assume to switches where they can talk to
each other.
Personally, I was under the impression the cables are required and that
you can't do a virtual IP connection between HMC and SE in an HMA. But
that's just my impression - I never asked IBM about it.
On 12/18/2024 10:18 AM, Chicklon, Thomas wrote:
Each of our z16s required 10 copper connections spread across 2 separate LANs /
switches.
A1: Our z16s came with 2 HMAs (Hardware Management Appliance) in each z16, each
redundantly takes care of the SE and HMC functions. As before there are two
separate SEs, and now there are two HMCs for each z16. No cabling was required
for connectivity between HMC and SE functions in a single HMA.
A2: Each of our z16s has 10 copper network connections. Two for each of the
HMCs (4 total), two for each of the SEs (4 total), and two additional for ETS
ports assuming you are using an external time server. These ports are not in
either of the HMAs, they are totally separate. Note that this functions used to
be in the HMCs. I have a diagram I got from IBM that shows these 10 connections
on the z16 and which network they get plugged into.
A3: We can see all of our z16s from all of our HMCs, even though they ae spread
across multiple sites. One of each of the HMC connections is to your intranet,
and the IBM SSR made the definitions in the HMCs.
Tom Chicklon
Fifth Third Bank
This e-mail transmission contains information that is confidential and may be
privileged. It is intended only for the addressee(s) named above. If you
receive this e-mail in error, please do not read, copy or disseminate it in any
manner. If you are not the intended recipient, any disclosure, copying,
distribution or use of the contents of this information is prohibited. Please
reply to the message immediately by informing the sender that the message was
misdirected. After replying, please erase it from your computer system. Your
assistance in correcting this error is appreciated.
----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [email protected] with the message: INFO IBM-MAIN
----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [email protected] with the message: INFO IBM-MAIN
