I suspect "connection" in this context means the opening of a TCP/IP
socket, which establishes the path between ports on two nodes, and that
all subsequent packets follow that established path. That would
suggest that transmission of a single file by one FTP instance would
still be constrained to the bandwidth of a single interface. My
understanding of load balancing is that it distributes aggregate load
over multiple interfaces by spreading multiple transactions over
multiple paths rather than spreading multiple packets for the same
transaction over multiple paths--so alternate routes for packets of a
single FTP transaction wouldn't be an issue.
If your object is to make two 1 Gbps interfaces behave as one 2-Gbps
interface for a single transaction, I believe that would be closer to
what is called Ethernet bonding of interfaces. I know Linux can support
this if you also have an Ethernet switch that can support bonding (and
that can support aggregate rates of 2Gbps). I don't know if that is
supported on z/OS. My understanding is that this can allow packets
associated with the same TCP/IP socket to follow different physical
paths, but the unit of transmission is still a packet. FTP transmitting
a large file supports multiple packets in flight before having to
receive a response back so it should be able to effectively utilize the
aggregate bandwidth by spreading those packets over multiple
interfaces. If FTP is in an interaction where a single packet is sent
and a response packet must be received before proceeding, you would
still be constrained by the bandwidth of a single interface because each
individual packet still travels over one physical interface.
JC Ewing
On 5/26/23 10:33, Steve Thompson wrote:
I have a question about the alternating of packets.
If one is using an MFT product with encryption and hand-shakes, will
the alternating packets between routes not cause the "connection" and
data xfer(s) to fail?
I'm asking because I know just enough about Network traffic to be
truly dangerous -- which means I know how to specify an IP address and
port#, and not much more.
Steve Thompson
On 5/26/2023 11:25 AM, John S. Giltner, Jr. wrote:
z/OS can do load balancing if you have mutiple equal cost routes
defined, one route for each OSA and I think they could be the same
route, something like:
BeginRoutes
route default = OSA_INTERFACE1
route default = OSA_INTERFACE2
ENDRoutes
You could use either default, or code routes for specific
hosts/subnets. Using default will load balance all outbound traffic,
coding more specific routes will just load blance the traffic for
hosts matching those routes.
You then add add one of the following statements to your IPCONFIG
statement.
MULTIPATH PERCONNECTION
MULTIPATH PERPACKET
First one will have z/OS alternate which route it takes per TCP
connection. Connection request #1 get path/route #1, request #2 gets
path/route #2. Depending on timing all 3 jobs could still get sent
out the same OSA, but you will be using both OSA's so it won't impact
all traffic.
Second one does the same thing, but per packet. More overhead but
both OSA's will be used "equally".
No matter what you do, depending on your network setup either one of
these or, as Keith suggested, defining a ROUTE via a specific
Interface you could overload your network. If your whole
infrastructure is 1 Gbps Ethernet, your z/OS system can now push ~2
Gbps through the network.
On Thu, 25 May 2023 19:37:10 +0100, Keith Gooding <[email protected]>
wrote:
Hi Rex
Networking is not my speciality but you should be able to add a HOST
route - see the BEGINROUTES statement in IP Config Reference.
Something like this:
ROUTE windows server IP address. HOST = OSA_INTERFACE2
where OSA_INTERFACE2 is the interface which you want to use.
This example assumes that the server is on the same subnet as the
adapter - change - to the router IP address if not.
No guarantees.
Keith Gooding
Sent from my iPad
On 25 May 2023, at 16:41, Pommier, Rex <[email protected]>
wrote:
Hi all,
I have a question about routing FTP traffic. First a bit about the
environment. Z14-zr1 with (2) 1-GbE OSA adapters shared across 3
LPARs. The 2 adapters are not in a VIPA configuration. Right now
on this LPAR, only 1 of the adapters is defined to TCP/IP. I can
easily get the second OSA configured into TCP/IP on the LPAR so
that's not an issue.
The situation/question. I have 3 jobs that run on the mainframe
that all 3 initiate an FTP process to Windows servers. Between the
3 jobs they are pushing between 1.5 and 2 terabytes to the
servers. The jobs are currently single threaded and from looking
at the FTP output, they are pushing the Ethernet adapter that is in
use at 100%. My question is this: If I configure the second
adapter, is there a way that I can force one of these jobs to use
one of the OSA adapters and the other 2 to go to the second
adapter? From what I recall, z/OS doesn't do any kind of trunking
or load balancing so setting up a VIPA won't improve throughput by
using both adapters. I've meandered through the IP configuration
reference and see nothing that would give me this capability.
TIA
Rex
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