APA and Multi IP

[Fayez]

Hi,

Server rx6600
OS HP-UX 11i v3
I am studding to configure link aggregate and fail over group using three network adapter, two of them already configured with different IP addresses.
My question is: is it possible to configure more than one IP address on APA interface???

[Mel Burslan · Accepted solution]

Since you are on 11i version 3, you should theoretically be able to do this. I have never tried this but, being the admin of a majorly 11.11 and some 11.23 aserver farm, it is a sore point for us not being able to do VLAN trunking on APA interfaces on hpux platform, while AIX and Linux provide this functionality without any problems. When inquired HP about it, I was told that version 11.31 supports it.

[Alzhy]

Yes it is possible. The IP however will need to be on the same subnet as your main APA Interface.

For example if your APA interface is lan900 and it's IP is say 10.10.10.100, you can assign Virtual IPs in the 10.10.10.0 network.

ifconfig lan900:1 10.10.10.101 netmask 255.255.255.0

After that, you will now have 2 IP's plumbed up on lan900 - the 10.10.10.100 primary address and the lan900:1 "virtual IP" 10.10.10.101 - you can check with "netstat -ian"

HTH.

[Mel Burslan]

@ Alzhy : Yes you can do it that way as long as you keep in the same subnet regardless of the OS version. When you introduce the VLAN Trunking/Tagging into the play, then you have to have 11i v3 at the least. There is no support for this on 11.11 or 11.23. Sore point in my environment and I hear people poo-poo in hpux in favor of AIX, which is capable of doing this for years.

[rick jones]

As far as IP/the transport is concerned, an APA interface is no different from any other interface. As you can assign multiple IPs to a single physical interface you can assign multiple IPs to an APA interface.

At the risk of sticking my foot in my mouth, I'm not sure why they would have to be in the same IP subnet and didn't think they did. My very bit-error riddled DIMM wetware memory seems to recall such a limitation back in the days of 10.20 but not with the 11.X stack.

[Alzhy]

Rick -- mon ami et NetExperto par exellance, you saying it is possible to assign VIPs that are on a different network on an APA pair?

Can you please elaborate? Networking is not my forte and our Network team simply tels me what to do.

[Mel Burslan]

@Rick,

This 11.31 requirement for VLAN tagging/trunking over APA interfaces, is something I got from my ASE quite a while ago.It might still work but I got the word that HP won't support the configuration. Ans since we want to employ this approach for our production servers, we could not risk it.Official support for this have started on 11.31 I was told. My foot might be in my mouth for saying that but this is what I heard...

[Fayez]

Hi all,

Thanks all for your replay, as I understood from your replay, It is possible to configure different IPs with different subnets on the same APA interface, but I need to introduce VLAN Tagging/Trunking into the play, am I right???

As I read the Admin manual for APA, I found it possible now to do VLAN Tagging/Trunking as Mel said first, and confirmed by Rick..

[Mel Burslan]

Fayez,

Make sure you work closely with your network adminisy=trator, a senior one at that. I have had bad experiences with HPUX vlan tagging (on a single interface, not APA) and Cisco core and distribution switches. We had to pull in the only CCIE in our corporation to figure out what went wrong. And it took quite a while even for him to figure it out. The tagging has to be done very meticulously on the network end for problem free operation in the future and ask the network engineers to document what they did, step-by-step, in the order they did it. Because this order will come to play a big role if you need to rebuild this configuration in the future. Not easy...

[Yogesh M Puranik]

Hey Fayez,


It is possible to configure more than one IP address on APA interface provided tht IP's should match same subnet/in a same network.


Rgds
YMP

[Fayez]

Hi Mel,

All switches we had is HP procurve, I will start to review our network, and put down a plan of how to implement this one..


Thanks...

[rick jones]

Whether different IP subnets need to run over different VLANs is a matter of choice. You can run multiple IP subnets over the same broadcast domain (VLAN) and it will work just fine for some definition of fine, the difference between doing that and using multiple VLANs is that without the different VLANs, it is possible for a node in IP subnet A to talk "directly" to a node in IP subnet B without having to go through a router.