does creating virtual IP's over physical NIC's only provide redundancy,
or will it also provide some performance benefit as well?
(will it use what ever physical interface is faster, or will ALWAYS use
one, unless it has failed, and then use the other???)
On 10/2/2013 11:34 AM, DrFranken wrote:
Yes thanks for reminding us, this is available and it does work!
Considerations and thinking for this option to assign the LCLIFC:
1) ONLY ONE can be assigned to each physical interface IP.
2) The interface must be shut down to change this interface.
Note that you can assign multiple physical interfaces to each Ethernet
line. Then you could assign a different virtual IP as the LCLIFC to each
of the IPs on the line. Cool. But this creates another ambiguity as
there are now multiple IPs again!
This is also where I point out that some applications can be bound to a
single IP address. You may want to look into this for the application so
that you remove the ambiguity with this.
Finally one other thing that can bite you in the butt with redundancy is
that some vendors (banks come to mind) restrict access by MAC address.
This means you'll need to assure that if you fail over to another
Ethernet line that the MAC address of that line is also allowed through
- Larry "DrFranken" Bolhuis
On 10/1/2013 2:57 PM, Evan Harris wrote:
In addition to what the Dr has said, when using Proxy ARP for IP
I found it useful to specofy the Associated local interface (LCLIFC)
parameter on the IP Interface definition (ADDIPIFC). This helped a good
deal with the firewall issues.
The Proxy ARP box visible in Ops Navigator must be ticked - you have
this from Ops Nav (or at least used to) there is/was not green screen
On Wed, Oct 2, 2013 at 4:04 AM, Midrange <midrange@xxxxxxxxxxxx> wrote:
1) at least on additional Ethernet port, preferable NOT on thee same
card as the current production interface also preferably to a different
2) TWO additional IP addresses in the same subnet as the production
A) create a new IP interface using one of the new IP addresses and
attach it to the current Ethernet line description, and start the
B) create a new line description for the new port you are adding and
vary it on.
C) create a new IP interface using the other of the new IP addresses and
attach it to the new line description, and start this interface.
D) using DSPLIND display each of the two lines and record the smallest
of the two frame sizes.
E) now in IBM i Navigator create a connection to the server using one of
the two new interfaces, NOT the current production interface. (It will
become apparent in a moment why this is important. )
F) locate networking, TCP/IP and IPv4. Expand that to see the IP
interfaces. You should see the three for this effort plus 127.0.0.1
used for tools like iTerra, Maxava, Mimix, PowerHA etc.
G) Right click on the production IP address and end it. DID I MENTION
THIS WOULD BE DISRUPTIVE? Yeah could be! This is also why you don't
be connected to this IP address at this time. :-)
H) Now delete the production IP from the server.
I) Now create a new IP Interface that is type VIrtual. Attributes
- Use the Production IP address
- Subnet mask of 255.255.255.255 Seems just wrong but it is correct.
- On the advanced tab check the Proxy Arp box.
- On the advanced tab enter the frame size recorded in D above.
- IF you prefer that traffic flow over one of the two lines, select
that as the preferred interface. Otherwise leave this alone. You
this if one of the lines is 1G and the other is 100M, prefer the 1G
J) Now start the interface and you're back in business.
I) You can now pull either line out or fail a card or switch port or cut
a cable and the users will not know.
II) Traffic will be flowing almost exclusively over just one of the
lines. If that's the one that fails then traffic moves to the other line
immediately. The system will issue a gratuitous ARP to inform
that subnet that the MAC address of the interface has changed.
III) IMPORTANT: Traffic that is INITIATED from the server (e.g. EDI or
bank transmissions) will come from one of the two new interfaces now,
NEVER from the production IP. This has firewall implications, understand
IV) For enhanced reliability set the CMNRCYLMT parm on the Ethernet
line descriptions to (1 0) for infinite retries. You can do this
lines are varied on.
V) This works on V5R3 and up.
Done from memory while off line, please forgive any slight discrepancies
in terminology to what's on the screen.
Sent from my iPad
On Oct 1, 2013, at 10:07 AM, Vikhyath Kamath <vikyat_kaamath@xxxxxxxxx>wrote:
(ITERA) and other is accessed by users.
*This message was transferred with a trial version of CommuniGate(r)
We use IBM i V6R1.
We have a 2 or more LAN adaptors in each LPAR. We use one IP for HA
Thanks and Regards,
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